Mercedes-Benz first series automatic transmission

Mercedes-Benz K4A 025
K4B 050 · K4C 025 · K4A 040 W3A 040 · W3B 050 · W4B 025
W4A 018 · W4B 035
Mercedes-Benz K4A 025 K4B 050 · K4C 025 · K4A 040 W3A 040 · W3B 050 · W4B 025 W4A 018 · W4B 035
	K4A 025
Overview
Manufacturer	Daimler AG
Production	1961–1983
Body and chassis
Class	3 and 4-speed longitudinal automatic transmission
Chronology
Successor	4G-Tronic

The Mercedes-Benz first series of automatic transmission was produced from 1961 to 1983 in 4- and 3-speed variants for Mercedes-Benz passenger cars. In addition, variants for commercial vehicles were offered until the mid-1990s.

This transmission was the first Mercedes-Benz automatic transmission in-house developing.^[1] Before this, the company used semi-automatic systems like a vacuum-powered shifting for overdrive or the "Hydrak" hydraulic automatic clutch system. Alternatively, they bought automatic transmissions of other vendors, such as the Detroit gear 3-speed automatic transmission from BorgWarner for the 300 c and 300 d (not to be confused with the later 300 D and its successors).

The automatic transmissions are for engines with longitudinal layout for rear-wheel-drive layout passenger cars. The control of the fully automatic system is fully hydraulic and it uses electrical wire only for the kickdown solenoid valve and the neutral safety switch.

Physically, it can be recognized for its pan which uses 16 bolts.

Key Data

Gear Ratios^[a]
Model	Type	First Deliv- ery	Gear					Total Span			Avg. Step	Components		Nomenclature
Model	Type	First Deliv- ery	R	1	2	3	4	Nomi- nal	Effec- tive	Cen- ter	Avg. Step	Total	per Gear^[b]	Cou- pling	Gears Count	Ver- sion	Maximum Input Torque

K4A 025	w/o	1961 ^[2]^[A]	−4.145	3.979	2.520	1.579	1.000	3.979	3.979	1.995	1.585	2 Gearsets 3 Brakes 3 Clutches	2.000	K^[c]	4^[b]	A	25 kp⋅m (181 lb⋅ft)

K4B 050^[d]	w/o	1964^[e]	−4.145	3.979	2.459	1.579	1.000	3.979	3.979	1.995	1.585	3 Gearsets 3 Brakes 2 Clutches	2.000	K^[c]	4^[b]	B	50 kp⋅m (362 lb⋅ft)
K4C 025 K4A 040 W4B 025	722.2 722.2 722.1	1967^[B] 1969 1972^[B]	−5.478	3.983	2.386	1.461	1.000	3.983	3.983	1.996	1.585			K^[c] K^[c] W^[f]^[4]	4^[b]	C A B	25 kp⋅m (181 lb⋅ft) 40 kp⋅m (289 lb⋅ft) 25 kp⋅m (181 lb⋅ft)
W4A 018^[g]	720.1	1975	−5.499	4.006	2.391	1.463	1.000	4.006	4.006	2.001	1.588			W^[f]	4^[b]	A	18 kp⋅m (130 lb⋅ft)
W4B 035^[h]	TBD	1975	−5.881	4.176	2.412	1.462	1.000	4.176	4.176	2.043	1.610			W^[f]	4^[b]	B	35 kp⋅m (253 lb⋅ft)

W3A 040 W3A 050 W3A 050 reinf.^[i]	720.0 722.0 722.0	1971 1973 1975	−1.836	2.306	1.461	1.000		2.306	1.836	1.519	1.519	2 Gearsets 3 Brakes 2 Clutches	2.333	W^[f]	3^[b]	A	40 kp⋅m (289 lb⋅ft) 50 kp⋅m (362 lb⋅ft) 56 kp⋅m (405 lb⋅ft)

^ Differences in gear ratios have a measurable, direct impact on vehicle dynamics, performance, waste emissions as well as fuel mileage ^ ^a ^b ^c ^d ^e ^f ^g Forward gears only ^ ^a ^b ^c ^d Fluid coupling · German: Kupplung or Flüssigkeitskupplung ^ K4B 050: for the 6.3 L engine M 100 of the 600 and 300 SEL 6.3 ^ Unveiled in September 1963 at the International Motor Show in Frankfurt, it went into production in September 1964 ^ ^a ^b ^c ^d Torque converter · German: Wandler or Drehmomentwandler ^ W4A 018: for light-duty trucks and vans up to 5,600 kg (12,350 lb) and off-road vehicles^[B]^[C] ^ W4B 035: for medium-duty trucks up to 13,000 kg (28,660 lb)^[D]^[E] ^ W3A 050 reinforced: for the 6.8 L engine M 100 of the 450 SEL 6.9

1961: K4A 025
— 4-Speed Transmission With 2 Planetary Gearsets —

Layout

The K4A 025 is the first of the series, launched in April 1961 for the W 111 220 SEb, later replaced with the more reliable K4C 025 (type 722.2). It is a 4-speed unit and uses fluid coupling (also referred in some manuals as hydraulic/automatic clutch).

The design of the transmission results in poor shifting comfort, which does not meet Mercedes-Benz standards. This applies in particular to the change from 2nd to 3rd gear (and vice versa), which requires a group change, i.e. affects all shift elements.

Specifications

For this first 4-speed model^[a] 8 main components^[b] are used. It is the only exemption which uses only 2 planetary gearsets for 4 speeds.

Gear Ratio Analysis^[c]
In-Depth Analysis^[d] With Assessment And Torque Ratio^[e] And Efficiency Calculation^[f]		Planetary Gearset: Teeth^[g]		Count	Nomi- nal^[h] Effec- tive^[i]	Cen- ter^[j]
		Simple		Count	Nomi- nal^[h] Effec- tive^[i]	Avg.^[k]

Model Type	Version First Delivery	S₁^[l] R₁^[m]	S₂^[n] R₂^[o]	Brakes Clutches	Ratio Span	Gear Step^[p]
Gear	R		1	2	3	4
Gear Ratio^[d]	${i_{R}}$ ^[d]		${i_{1}}$ ^[d]	${i_{2}}$ ^[d]	${i_{3}}$ ^[d]	${i_{4}}$ ^[d]
Step^[p]	$-{\frac {i_{R}}{i_{1}}}$ ^[q]		${\frac {i_{1}}{i_{1}}}$	${\frac {i_{1}}{i_{2}}}$ ^[r]	${\frac {i_{2}}{i_{3}}}$	${\frac {i_{3}}{i_{4}}}$
Δ Step^[s]^[t]				${\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}$	${\tfrac {i_{2}}{i_{3}}}:{\tfrac {i_{3}}{i_{4}}}$
Shaft Speed	${\frac {i_{1}}{i_{R}}}$		${\frac {i_{1}}{i_{1}}}$	${\frac {i_{1}}{i_{2}}}$	${\frac {i_{1}}{i_{3}}}$	${\frac {i_{1}}{i_{4}}}$
Δ Shaft Speed^[u]	$0-{\frac {i_{1}}{i_{R}}}$		${\tfrac {i_{1}}{i_{1}}}-0$	${\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}$	${\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}$	${\tfrac {i_{1}}{i_{4}}}-{\tfrac {i_{1}}{i_{3}}}$
Efficiency $\eta _{n}$ ^[f]	${\tfrac {T_{2;R}}{T_{1;R}}}:{i_{R}}$		${\tfrac {T_{2;1}}{T_{1;1}}}:{i_{1}}$	${\tfrac {T_{2;2}}{T_{1;2}}}:{i_{2}}$	${\tfrac {T_{2;3}}{T_{1;3}}}:{i_{3}}$	${\tfrac {T_{2;4}}{T_{1;4}}}:{i_{4}}$
Torque Ratio^[e]	$\mu _{R}$ ^[e]		$\mu _{1}$ ^[e]	$\mu _{2}$ ^[e]	$\mu _{3}$ ^[e]	$\mu _{4}$ ^[e]
Efficiency $\eta _{n}$ ^[f]	${\frac {\mu _{R}}{i_{R}}}$ ^[f]		${\frac {\mu _{1}}{i_{1}}}$ ^[f]	${\frac {\mu _{2}}{i_{2}}}$ ^[f]	${\frac {\mu _{3}}{i_{3}}}$ ^[f]	${\frac {\mu _{4}}{i_{4}}}$ ^[f]

K4A 025 w/o	25 kp⋅m (245 N⋅m; 181 lb⋅ft) 1961^[2]^[A]	50 76	44 76	3 3	3.9789 3.9789	1.9947
K4A 025 w/o	25 kp⋅m (245 N⋅m; 181 lb⋅ft) 1961^[2]^[A]	50 76	44 76	3 3	3.9789 3.9789	1.5846^[p]
Gear	R		1	2	3	4
Gear Ratio^[d]	−4.1455 $-{\tfrac {228}{55}}$		3.9789 ${\tfrac {378}{95}}$	2.5200^[p]^[t] ${\tfrac {63}{25}}$	1.5789^[p] ${\tfrac {30}{19}}$	1.0000 ${\tfrac {1}{1}}$
Step	1.0418		1.0000	1.5789^[p]	1.5960^[p]	1.5789
Δ Step^[s]				0.9893^[t]	1.0108
Speed	-0.9598		1.0000	1.5789	2.5200	3.9789
Δ Speed	0.9598		1.0000	0.5789	0.9411	1.4589
Torque Ratio^[e]	–4.0111 –3.9447		3.9021 3.8640	2.4896 2.4744	1.5674 1.5616	1.0000
Efficiency $\eta _{n}$ ^[f]	0.9676 0.9516		0.9807 0.9711	0.9879 0.9819	0.9927 0.9890	1.0000

Actuated Shift Elements
Brake B1^[v]			❶	❶
Brake B2^[w]			❶		❶
Brake B3^[x]	❶
Clutch K1^[y]					❶	❶
Clutch K2^[z]				❶		❶
Clutch K3^[aa]	❶
Geometric Ratios: Speed Conversion
Gear Ratio^[d] R & 2 & 4 Ordinary^[ab] Elementary Noted^[ac]	$i_{R}=-{\frac {R_{1}(S_{2}+R_{2})}{S_{1}S_{2}}}$			$i_{2}={\frac {S_{1}+R_{1}}{S_{1}}}$		$i_{4}={\frac {1}{1}}$
	$i_{R}=-{\tfrac {R_{1}}{S_{1}}}\left(1+{\tfrac {R_{2}}{S_{2}}}\right)$			$i_{2}=1+{\tfrac {R_{1}}{S_{1}}}$		$i_{4}={\frac {1}{1}}$

Gear Ratio^[d] 1 & 3 Ordinary^[ab] Elementary Noted^[ac]	$i_{1}={\frac {(S_{1}+R_{1})(S_{2}+R_{2})}{S_{1}R_{2}}}$				$i_{3}={\frac {S_{2}+R_{2}}{R_{2}}}$
Gear Ratio^[d] 1 & 3 Ordinary^[ab] Elementary Noted^[ac]	$i_{1}=\left(1+{\tfrac {R_{1}}{S_{1}}}\right)\left(1+{\tfrac {S_{2}}{R_{2}}}\right)$				$i_{3}=1+{\tfrac {S_{2}}{R_{2}}}$
Kinetic Ratios: Torque Conversion
Torque Ratio^[e] R & 2 & 4	$\mu _{R}=-{\tfrac {R_{1}}{S_{1}}}\eta _{0}\left(1+{\tfrac {R_{2}}{S_{2}}}\eta _{0}\right)$			$\mu _{2}=1+{\tfrac {R_{1}}{S_{1}}}\eta _{0}$		$\mu _{4}={\tfrac {1}{1}}$

Torque Ratio^[e] 1 & 3	$\mu _{1}=\left(1+{\tfrac {R_{1}}{S_{1}}}\eta _{0}\right)\left(1+{\tfrac {S_{2}}{R_{2}}}\eta _{0}\right)$				$\mu _{3}=1+{\tfrac {S_{2}}{R_{2}}}\eta _{0}$

^ plus 1 reverse gear ^ 2 simple planetary gearsets, 3 brakes, 3 clutches ^ Revised 14 January 2026 Nomenclature $S_{n}=$ sun gear: number of teeth $R_{n}=$ ring gear: number of teeth $\color {gray}{C_{n}=}$ carrier or planetary gear carrier (not needed) $s_{n}=$ sun gear: shaft speed $r_{n}=$ ring gear: shaft speed $c_{n}=$ carrier or planetary gear carrier: shaft speed With $n=$ gear is $i_{n}=$ gear ratio or transmission ratio $\omega _{1;n}=\omega _{t}=$ shaft speed shaft 1: input (turbine) shaft $\omega _{2;n}=$ shaft speed shaft 2: output shaft $T_{1;n}=T_{t}=$ torque shaft 1: input (turbine) shaft $T_{2;n}=$ torque shaft 2: output shaft $\mu _{n}=$ torque ratio or torque conversion ratio $\eta _{n}=$ efficiency $i_{0}=$ stationary gear ratio $\eta _{0}=$ (assumed) stationary gear efficiency ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Gear Ratio (Transmission Ratio) $i_{n}$ — Speed Conversion — The gear ratio $i_{n}$ is the ratio of input shaft speed $\omega _{1;n}$ to output shaft speed $\omega _{2;n}$ and therefore corresponds to the reciprocal of the shaft speeds $i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}$ ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Torque Ratio (Torque Conversion Ratio) $\mu _{n}$ — Torque Conversion — The torque ratio $\mu _{n}$ is the ratio of output torque $T_{2;n}$ to input torque $T_{1;n}$ minus efficiency losses and therefore corresponds (apart from the efficiency losses) to the reciprocal of the shaft speeds too $\mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}$ whereby $\eta _{n;\eta _{0}}$ may vary from gear to gear according to the formulas listed in this table and $0\leq \eta _{n;\eta _{0}}\leq 1$ ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Efficiency The efficiency $\eta _{n}$ is calculated from the torque ratio in relation to the gear ratio (transmission ratio) $\eta _{n}={\frac {\mu _{n}}{i_{n}}}$ Power loss for single meshing gears is in the range of 1 % to 1.5 % helical gear pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range Corridor for torque ratio and efficiency in planetary gearsets, the stationary gear ratio $i_{0}$ is formed via the planetary gears and thus by two meshes for reasons of simplification, the efficiency for both meshes together is commonly specified there the efficiencies $\eta _{0}$ specified here are based on assumed efficiencies for the stationary ratio $i_{0}$ of $\eta _{0}=0.9800$ (upper value) and $\eta _{0}=0.9700$ (lower value) for both interventions together The corresponding efficiency for single-meshing gear pairs is ${\eta _{0}}^{\tfrac {1}{2}}$ at $0.9800^{\tfrac {1}{2}}=0.98995$ (upper value) and $0.9700^{\tfrac {1}{2}}=0.98489$ (lower value) ^ Layout Input and output are on opposite sides Planetary gearset 1 is on the input (turbine) side Input shafts is S₁ and, if actuated, C₁ Output shaft is C₂ ^ Total Ratio Span (Total Gear/Transmission Ratio) Nominal ${\frac {\omega _{2;n}}{\omega _{2;1}}}={\frac {\frac {\omega _{2;n}}{\omega _{2;1}\omega _{2;n}}}{\frac {\omega _{2;1}}{\omega _{2;1}\omega _{2;n}}}}={\frac {\frac {1}{\omega _{2;1}}}{\frac {1}{\omega _{2;n}}}}={\frac {\frac {\omega _{t}}{\omega _{2;1}}}{\frac {\omega _{t}}{\omega _{2;n}}}}={\frac {i_{1}}{i_{n}}}$ A wider span enables the downspeeding when driving outside the city limits increase the climbing ability when driving over mountain passes or off-road or when towing a trailer ^ Total Ratio Span (Total Gear Ratio/Total Transmission Ratio) Effective ${\frac {\omega _{2;n}}{max(\omega _{2;1};\|\omega _{2;R}\|)}}={\frac {min(i_{1};\|i_{R}\|)}{i_{n}}}$ The span is only effective to the extent that the reverse gear ratio matches that of 1st gear see also Standard R:1 Digression Reverse gear is usually longer than 1st gear the effective span* is therefore of central importance for describing the suitability of a transmission* because in these cases, the nominal spread conveys a misleading picture which is only unproblematic for vehicles with high specific power Market participants Manufacturers naturally have no interest in specifying the effective span Users have not yet formulated the practical benefits that the effective span has for them The effective span has not yet played a role in research and teaching Contrary to its significance the effective span* has therefore not yet been able to establish itself* either in theory or in practice. End of digression ^ Ratio Span's Center $(i_{1}i_{n})^{\frac {1}{2}}$ The center indicates the speed level of the transmission Together with the final drive ratio it gives the shaft speed level of the vehicle ^ Average Gear Step $\left({\frac {\omega _{2;n}}{\omega _{2;1}}}\right)^{\frac {1}{n-1}}=\left({\frac {i_{1}}{i_{n}}}\right)^{\frac {1}{n-1}}$ There are $n-1$ gear steps between $n$ gears with decreasing step width the gears connect better to each other shifting comfort increases ^ Sun 1: sun gear of gearset 1 ^ Ring 1: ring gear of gearset 1 ^ Sun 2: sun gear of gearset 2 ^ Ring 2: ring gear of gearset 2 ^ ^a ^b ^c ^d ^e ^f ^g Standard 50:50 — 50 % Is Above And 50 % Is Below The Average Gear Step — With steadily decreasing gear steps (yellow highlighted line Step) and a particularly large step from 1st to 2nd gear the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger and the upper half of the gear steps (between the large gears; rounded up, here the last 2) is always smaller than the average gear step (cell highlighted yellow two rows above on the far right) lower half: smaller gear steps are a waste of possible ratios (red bold) upper half: larger gear steps are unsatisfactory (red bold) ^ Standard R:1 — Reverse And 1st Gear Have The Same Ratio — The ideal reverse gear has the same transmission ratio as 1st gear no impairment when maneuvering especially when towing a trailer a torque converter can only partially compensate for this deficiency Plus 11.11 % minus 10 % compared to 1st gear is good Plus 25 % minus 20 % is acceptable (red) Above this is unsatisfactory (bold) ^ Standard 1:2 — Gear Step 1st To 2nd Gear As Small As Possible — With continuously decreasing gear steps (yellow marked line Step) the largest gear step is the one from 1st to 2nd gear, which for a good speed connection and a smooth gear shift must be as small as possible A gear ratio of up to 1.6667:1 (5:3) is good Up to 1.7500:1 (7:4) is acceptable (red) Above is unsatisfactory (bold) ^ ^a ^b From large to small gears (from right to left) ^ ^a ^b ^c Standard STEP — From Large To Small Gears: Steady And Progressive Increase In Gear Steps — Gear steps should increase: Δ Step (first green highlighted line Δ Step) is always greater than 1 As progressive as possible: Δ Step is always greater than the previous step Not progressively increasing is acceptable (red) Not increasing is unsatisfactory (bold) ^ Standard SPEED — From Small To Large Gears: Steady Increase In Shaft Speed Difference — Shaft speed differences should increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one 1 difference smaller than the previous one is acceptable (red) 2 consecutive ones are a waste of possible ratios (bold) ^ Blocks R₁ ^ Blocks S₂ ^ Also BR (brake for reverse gear · German: Bremse für Rückwärtsgang) · blocks C₁ and R₂ ^ Couples C₁ and R₂ with the input (turbine) ^ Couples C₁ and R₂ with S₂ ^ Also KR (clutch for reverse gear · German: Kupplung für Rückwärtsgang) · couples R₁ with S₂ ^ ^a ^b Ordinary Noted For direct determination of the gear ratio ^ ^a ^b Elementary Noted Alternative representation for determining the transmission ratio Contains only operands With simple fractions of both central gears of a planetary gearset Or with the value 1 As a basis For reliable And traceable Determination of the torque conversion ratio and efficiency

1964: K4B 050 And Follow-Up Products
— 4-Speed Transmissions With 3 Planetary Gearsets —

Layout

The Mercedes-Benz 600, unveiled in September 1963 at the International Motor Show in Frankfurt, it went into production in September 1964 and was the first post-war "Grand Mercedes", powered by the Mercedes-Benz M100 engine. This made a gearbox for the highest demands of luxury vehicles necessary. The design of the gearbox in the range was out of the question from the outset. The introduction of the 600 was therefore taken as an opportunity to develop a completely new design for the automatic transmission.

Models

1964: K4B 050

The first model with this new layout was the K4B 050. Beside the new layout the number of pinions is doubled from 3 to 6 to handle the much higher torque of the big block V8 engine.

1967: K4C 025

After the satisfactory experience with the new design, it was adopted in 1967 for the new core model K4C 025 (Type 722.2) of the first automatic transmission series from Mercedes-Benz. With the small block V8 engine M 116, the K4A 040 (Type 722.2) was launched as a reinforced version of the same design.

1969: K4A 040

With the introduction of the V8 cylinder engines of the M 116 series with a displacement of 3.5 liters, the automatic transmission range was expanded to include the K4A 040 model, which is a reinforced version of the K4C 025 with the same gear ratios to accommodate the increased torque.

1972: W4B 025

When the torque converter technique was fully established, the fluid coupling was replaced by a torque converter for the smaller engines, which leads to the W4B 025 (type 722.1).^[4] Used in L4, L5 and L6 engines due to its lower torque output. In normal situations, it rests stationary in 2nd gear, but it will use 1st gear when the vehicle starts moving and throttle is applied^[6] or if L position is selected in gear selector.

Variants For Commercial Cars

The W4A 018 (type 720.1) was derived from the W4B 025 (type 722.1) for light-duty trucks and vans up to 5,600 kg (12,350 lb) and off-road vehicles,^[B]^[C] the W4B 035 from the W4B 025 (type 722.1) and K4A 040 (type 722.2) for medium-duty trucks up to 13,000 kg (28,660 lb).^[D]^[E] The main difference is the use of straight-cut planetary gearsets instead of helical-cut ones for better fuel efficiency at the price of lower noise comfort.

Specifications

For this second 4-speed models^[a] 8 main components^[b] are used.^[4]

Gear Ratio Analysis^[c]
In-Depth Analysis^[d] With Assessment And Torque Ratio^[e] And Efficiency Calculation^[f]		Planetary Gearset: Teeth^[g] Teeth			Count	Nomi- nal^[h] Effec- tive^[i]	Cen- ter^[j]
		Simpson		Simple	Count	Nomi- nal^[h] Effec- tive^[i]	Avg.^[k]

Model Type	Version First Delivery	S₁^[l] R₁^[m]	S₂^[n] R₂^[o]	S₃^[p] R₃^[q]	Brakes Clutches	Ratio Span	Gear Step^[r]
Gear		R		1	2	3	4
Gear Ratio^[d]		${i_{R}}$ ^[d]		${i_{1}}$ ^[d]	${i_{2}}$ ^[d]	${i_{3}}$ ^[d]	${i_{4}}$ ^[d]
Step^[r]		$-{\frac {i_{R}}{i_{1}}}$ ^[s]		${\frac {i_{1}}{i_{1}}}$	${\frac {i_{1}}{i_{2}}}$ ^[t]	${\frac {i_{2}}{i_{3}}}$	${\frac {i_{3}}{i_{4}}}$
Δ Step^[u]^[v]					${\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}$	${\tfrac {i_{2}}{i_{3}}}:{\tfrac {i_{3}}{i_{4}}}$
Shaft Speed		${\frac {i_{1}}{i_{R}}}$		${\frac {i_{1}}{i_{1}}}$	${\frac {i_{1}}{i_{2}}}$	${\frac {i_{1}}{i_{3}}}$	${\frac {i_{1}}{i_{4}}}$
Δ Shaft Speed^[w]		$0-{\tfrac {i_{1}}{i_{R}}}$		${\tfrac {i_{1}}{i_{1}}}-0$	${\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}$	${\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}$	${\tfrac {i_{1}}{i_{4}}}-{\tfrac {i_{1}}{i_{3}}}$
Torque Ratio^[e]		$\mu _{R}$ ^[e]		$\mu _{1}$ ^[e]	$\mu _{2}$ ^[e]	$\mu _{3}$ ^[e]	$\mu _{4}$ ^[e]
Efficiency $\eta _{n}$ ^[f]		${\frac {\mu _{R}}{i_{R}}}$ ^[f]		${\frac {\mu _{1}}{i_{1}}}$ ^[f]	${\frac {\mu _{2}}{i_{2}}}$ ^[f]	${\frac {\mu _{3}}{i_{3}}}$ ^[f]	${\frac {\mu _{4}}{i_{4}}}$ ^[f]

K4B 050^[x] w/o	51 kp⋅m (500 N⋅m; 369 lb⋅ft) 1964	50 76	44 76	44 76	3 2	3.9789 3.9789	1.9947
K4B 050^[x] w/o	51 kp⋅m (500 N⋅m; 369 lb⋅ft) 1964	50 76	44 76	44 76	3 2	3.9789 3.9789	1.5846^[r]
Gear		R		1	2	3	4
Gear Ratio^[d]		−4.1455 $-{\tfrac {228}{55}}$		3.9789 ${\tfrac {378}{95}}$	2.4589 ${\tfrac {1,168}{475}}$	1.5789^[v]	1.0000 ${\tfrac {1}{1}}$
Step		1.0418		1.0000	1.6182	1.5573	1.5789
Δ Step^[u]					1.0391	0.9863^[v]
Speed		-0.9598		1.0000	1.6182	2.5200	3.9789
Δ Speed		0.9598		1.0000	0.6182	0.9018	1.4589
Torque Ratio^[e]		–4.0111 –3.9447		3.9021 3.8640	2.4125 2.3896	1.5674 1.5616	1.0000
Efficiency $\eta _{n}$ ^[f]		0.9676 0.9516		0.9807 0.9711	0.9811 0.9718	0.9927 0.9890	1.0000

K4C 025 722.2	25 kp⋅m (245 N⋅m; 181 lb⋅ft) 1967^[B]	44 76	44 76	35 76	3 2	3.9833 3.9833	1.9958
K4C 025 722.2	25 kp⋅m (245 N⋅m; 181 lb⋅ft) 1967^[B]	44 76	44 76	35 76	3 2	3.9833 3.9833	1.5852^[r]
Gear		R		1	2	3	4
Gear Ratio^[d]		−5.4779^[s] $-{\tfrac {2,109}{385}}$		3.9833 ${\tfrac {1,665}{418}}$	2.3855^[t]^[v] ${\tfrac {5,439}{2,280}}$	1.4605^[r] ${\tfrac {111}{76}}$	1.0000 ${\tfrac {1}{1}}$
Step		1.3752^[s]		1.0000	1.6698^[t]	1.6333^[r]	1.4605
Δ Step^[u]					1.0223^[v]	1.1183
Speed		-0.7271		1.0000	1.6696	2.7273	3.9833
Δ Speed		0.7271		1.0000	0.6696	1.0575	1.2560
Torque Ratio^[e]		–5.2949 –5.2044		3.9080 3.8706	2.3406 2.3184	1.4513 1.4467	1.0000
Efficiency $\eta _{n}$ ^[f]		0.9666 0.9501		0.9811 0.9717	0.9812 0.9719	0.9937 0.9905	1.0000

K4A 040 722.2	40 kp⋅m (392 N⋅m; 289 lb⋅ft) 1969	44 76	44 76	35 76	3 2	3.9833 3.9833	1.9958
K4A 040 722.2	40 kp⋅m (392 N⋅m; 289 lb⋅ft) 1969	44 76	44 76	35 76	3 2	3.9833 3.9833	1.5852^[r]
Gear		R		1	2	3	4
Gear Ratio^[d]		−5.4779^[s]		3.9833	2.3855^[t]^[v]	1.4605^[r]	1.0000

W4B 025 722.1	25 kp⋅m (245 N⋅m; 181 lb⋅ft) 1972^[B]	44 76	44 76	35 76	3 2	3.9833 3.9833	1.9958
W4B 025 722.1	25 kp⋅m (245 N⋅m; 181 lb⋅ft) 1972^[B]	44 76	44 76	35 76	3 2	3.9833 3.9833	1.5852^[r]
Gear		R		1	2	3	4
Gear Ratio^[d]		−5.4779^[s]		3.9833	2.3855^[t]^[v]	1.4605^[r]	1.0000

W4A 018^[y] 720.1	18 kp⋅m (177 N⋅m; 130 lb⋅ft) 1975	46 80	46 80	37 80	3 2	4.0060 4.0060	2.0015
W4A 018^[y] 720.1	18 kp⋅m (177 N⋅m; 130 lb⋅ft) 1975	46 80	46 80	37 80	3 2	4.0060 4.0060	1.5882^[r]
Gear		R		1	2	3	4
Gear Ratio^[d]		−5.4994^[s] $-{\tfrac {4,680}{851}}$		4.0060 ${\tfrac {7,371}{1840}}$	2.3911^[t]^[v] ${\tfrac {1,339}{560}}$	1.4625^[r] ${\tfrac {117}{80}}$	1.0000 ${\tfrac {1}{1}}$
Step		1.3728^[s]		1.0000	1.6754^[t]	1.6349^[r]	1.4625
Δ Step^[u]					1.0248^[v]	1.1179
Speed		-0.7284		1.0000	1.6754	2.7391	4.0060
Δ Speed		0.7284		1.0000	0.6754	1.0637	1.2668
Torque Ratio^[e]		–5.3157 –5.2250		3.9301 3.8924	2.3459 2.3236	1.4533 1.4486	1.0000
Efficiency $\eta _{n}$ ^[f]		0.9666 0.9501		0.9811 0.9716	0.9811 0.9718	0.9937 0.9905	1.0000

W4B 035^[z] TBD	35 kp⋅m (343 N⋅m; 253 lb⋅ft) 1975	42 78	42 78	36 78	3 2	4.1758 4.1758	2.0435
W4B 035^[z] TBD	35 kp⋅m (343 N⋅m; 253 lb⋅ft) 1975	42 78	42 78	36 78	3 2	4.1758 4.1758	1.6103^[r]
Gear		R		1	2	3	4
Gear Ratio^[d]		−5.8810^[s] $-{\tfrac {2,223}{378}}$		4.1758 ${\tfrac {3,420}{819}}$	2.4115^[t]^[v] ${\tfrac {627}{260}}$	1.4615^[r] ${\tfrac {57}{39}}$	1.0000 ${\tfrac {1}{1}}$
Step		1.4083^[s]		1.0000	1.7360^[t]	1.6500^[r]	1.4615
Δ Step^[u]					1.0495^[v]	1.1289
Speed		-0.7101		1.0000	1.7316	2.8571	4.1758
Δ Speed		0.7101		1.0000	0.7316	1.1255	1.3187
Torque Ratio^[e]		–5.6845 –5.5874		4.0955 4.0556	2.3653 2.3425	1.4523 1.4477	1.0000
Efficiency $\eta _{n}$ ^[f]		0.9666 0.9501		0.9808 0.9712	0.9808 0.9714	0.9937 0.9905	1.0000

Actuated Shift Elements
Brake B1^[aa]					❶
Brake B2^[ab]				❶	❶	❶
Brake B3^[ac]		❶
Clutch K1^[ad]						❶	❶
Clutch K2^[ae]		❶		❶			❶
Geometric Ratios: Speed Conversion
Gear Ratio^[d] R & 1 Ordinary^[af] Elementary Noted^[ag]	$i_{R}=-{\frac {R_{1}(S_{3}+R_{3})}{S_{1}S_{3}}}$			$i_{1}={\frac {(S_{1}+R_{1})(S_{3}+R_{3})}{S_{1}R_{3}}}$
Gear Ratio^[d] R & 1 Ordinary^[af] Elementary Noted^[ag]	$i_{R}=-{\tfrac {R_{1}}{S_{1}}}\left(1+{\tfrac {R_{3}}{S_{3}}}\right)$			$i_{1}=\left(1+{\tfrac {R_{1}}{S_{1}}}\right)\left(1+{\tfrac {S_{3}}{R_{3}}}\right)$

Gear Ratio^[d] 2 & 3 & 4 Ordinary^[af] Elementary Noted^[ag]	$i_{2}={\frac {(S_{1}(S_{2}+R_{2})+R_{1}S_{2})(S_{3}+R_{3})}{S_{1}(S_{2}+R_{2})R_{3}}}$					$i_{3}={\frac {S_{3}+R_{3}}{R_{3}}}$
	$i_{2}=\left(1+{\tfrac {\tfrac {R_{1}}{S_{1}}}{1+{\tfrac {R_{2}}{S_{2}}}}}\right)\left(1+{\tfrac {S_{3}}{R_{3}}}\right)$				$i_{3}=1+{\tfrac {S_{3}}{R_{3}}}$		$i_{4}={\frac {1}{1}}$
Kinetic Ratios: Torque Conversion
Torque Ratio^[e] R & 1	$\mu _{R}=-{\tfrac {R_{1}}{S_{1}}}\eta _{0}\left(1+{\tfrac {R_{3}}{S_{3}}}\eta _{0}\right)$			$\mu _{1}=\left(1+{\tfrac {R_{1}}{S_{1}}}\eta _{0}\right)\left(1+{\tfrac {S_{3}}{R_{3}}}\eta _{0}\right)$

Torque Ratio^[e] 2 & 3 & 4	$\mu _{2}=\left(1+{\tfrac {{\tfrac {R_{1}}{S_{1}}}\eta _{0}}{1+{\tfrac {R_{2}}{S_{2}}}\cdot {\tfrac {1}{\eta _{0}}}}}\right)\left(1+{\tfrac {S_{3}}{R_{3}}}\eta _{0}\right)$				$\mu _{3}=1+{\tfrac {S_{3}}{R_{3}}}\eta _{0}$		$\mu _{4}={\frac {1}{1}}$

^ plus 1 reverse gear ^ 3 simple planetary gearsets, 3 brakes, 2 clutches ^ Revised 14 January 2026 Nomenclature $S_{n}=$ sun gear: number of teeth $R_{n}=$ ring gear: number of teeth $\color {gray}{C_{n}=}$ carrier or planetary gear carrier (not needed) $s_{n}=$ sun gear: shaft speed $r_{n}=$ ring gear: shaft speed $c_{n}=$ carrier or planetary gear carrier: shaft speed With $n=$ gear is $i_{n}=$ gear ratio or transmission ratio $\omega _{1;n}=\omega _{t}=$ shaft speed shaft 1: input (turbine) shaft $\omega _{2;n}=$ shaft speed shaft 2: output shaft $T_{1;n}=T_{t}=$ torque shaft 1: input (turbine) shaft $T_{2;n}=$ torque shaft 2: output shaft $\mu _{n}=$ torque ratio or torque conversion ratio $\eta _{n}=$ efficiency $i_{0}=$ stationary gear ratio $\eta _{0}=$ (assumed) stationary gear efficiency ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o Gear Ratio (Transmission Ratio) $i_{n}$ — Speed Conversion — The gear ratio $i_{n}$ is the ratio of input shaft speed $\omega _{1;n}$ to output shaft speed $\omega _{2;n}$ and therefore corresponds to the reciprocal of the shaft speeds $i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}$ ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Torque Ratio (Torque Conversion Ratio) $\mu _{n}$ — Torque Conversion — The torque ratio $\mu _{n}$ is the ratio of output torque $T_{2;n}$ to input torque $T_{1;n}$ minus efficiency losses and therefore corresponds (apart from the efficiency losses) to the reciprocal of the shaft speeds too $\mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}$ whereby $\eta _{n;\eta _{0}}$ may vary from gear to gear according to the formulas listed in this table and $0\leq \eta _{n;\eta _{0}}\leq 1$ ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Efficiency The efficiency $\eta _{n}$ is calculated from the torque ratio in relation to the gear ratio (transmission ratio) $\eta _{n}={\frac {\mu _{n}}{i_{n}}}$ Power loss for single meshing gears is in the range of 1 % to 1.5 % helical gear pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range Corridor for torque ratio and efficiency in planetary gearsets, the stationary gear ratio $i_{0}$ is formed via the planetary gears and thus by two meshes for reasons of simplification, the efficiency for both meshes together is commonly specified there the efficiencies $\eta _{0}$ specified here are based on assumed efficiencies for the stationary ratio $i_{0}$ of $\eta _{0}=0.9800$ (upper value) and $\eta _{0}=0.9700$ (lower value) for both interventions together The corresponding efficiency for single-meshing gear pairs is ${\eta _{0}}^{\tfrac {1}{2}}$ at $0.9800^{\tfrac {1}{2}}=0.98995$ (upper value) and $0.9700^{\tfrac {1}{2}}=0.98489$ (lower value) ^ Layout Input and output are on opposite sides Planetary gearset 1 is on the input (turbine) side Input (turbine) shaft is S₁ Output shaft is C₃ ^ Total Ratio Span (Total Gear/Transmission Ratio) Nominal ${\frac {\omega _{2;n}}{\omega _{2;1}}}={\frac {\frac {\omega _{2;n}}{\omega _{2;1}\omega _{2;n}}}{\frac {\omega _{2;1}}{\omega _{2;1}\omega _{2;n}}}}={\frac {\frac {1}{\omega _{2;1}}}{\frac {1}{\omega _{2;n}}}}={\frac {\frac {\omega _{t}}{\omega _{2;1}}}{\frac {\omega _{t}}{\omega _{2;n}}}}={\frac {i_{1}}{i_{n}}}$ A wider span enables the downspeeding when driving outside the city limits increase the climbing ability when driving over mountain passes or off-road or when towing a trailer ^ Total Ratio Span (Total Gear Ratio/Total Transmission Ratio) Effective ${\frac {\omega _{2;n}}{max(\omega _{2;1};\|\omega _{2;R}\|)}}={\frac {min(i_{1};\|i_{R}\|)}{i_{n}}}$ The span is only effective to the extent that the reverse gear ratio matches that of 1st gear see also Standard R:1 Digression Reverse gear is usually longer than 1st gear the effective span* is therefore of central importance for describing the suitability of a transmission* because in these cases, the nominal spread conveys a misleading picture which is only unproblematic for vehicles with high specific power Market participants Manufacturers naturally have no interest in specifying the effective span Users have not yet formulated the practical benefits that the effective span has for them The effective span has not yet played a role in research and teaching Contrary to its significance the effective span* has therefore not yet been able to establish itself* either in theory or in practice. End of digression ^ Ratio Span's Center $(i_{1}i_{n})^{\frac {1}{2}}$ The center indicates the speed level of the transmission Together with the final drive ratio it gives the shaft speed level of the vehicle ^ Average Gear Step $\left({\frac {\omega _{2;n}}{\omega _{2;1}}}\right)^{\frac {1}{n-1}}=\left({\frac {i_{1}}{i_{n}}}\right)^{\frac {1}{n-1}}$ There are $n-1$ gear steps between $n$ gears with decreasing step width the gears connect better to each other shifting comfort increases ^ Sun 1: sun gear of gearset 1 ^ Ring 1: ring gear of gearset 1 ^ Sun 2: sun gear of gearset 2 ^ Ring 2: ring gear of gearset 2 ^ Sun 3: sun gear of gearset 3 ^ Ring 3: ring gear of gearset 3 ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p Standard 50:50 — 50 % Is Above And 50 % Is Below The Average Gear Step — With steadily decreasing gear steps (yellow highlighted line Step) and a particularly large step from 1st to 2nd gear the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger and the upper half of the gear steps (between the large gears; rounded up, here the last 2) is always smaller than the average gear step (cell highlighted yellow two rows above on the far right) lower half: smaller gear steps are a waste of possible ratios (red bold) upper half: larger gear steps are unsatisfactory (red bold) ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Standard R:1 — Reverse And 1st Gear Have The Same Ratio — The ideal reverse gear has the same transmission ratio as 1st gear no impairment when maneuvering especially when towing a trailer a torque converter can only partially compensate for this deficiency Plus 11.11 % minus 10 % compared to 1st gear is good Plus 25 % minus 20 % is acceptable (red) Above this is unsatisfactory (bold) ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Standard 1:2 — Gear Step 1st To 2nd Gear As Small As Possible — With continuously decreasing gear steps (yellow marked line Step) the largest gear step is the one from 1st to 2nd gear, which for a good speed connection and a smooth gear shift must be as small as possible A gear ratio of up to 1.6667:1 (5:3) is good Up to 1.7500:1 (7:4) is acceptable (red) Above is unsatisfactory (bold) ^ ^a ^b ^c ^d ^e From large to small gears (from right to left) ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Standard STEP — From Large To Small Gears: Steady And Progressive Increase In Gear Steps — Gear steps should increase: Δ Step (first green highlighted line Δ Step) is always greater than 1 As progressive as possible: Δ Step is always greater than the previous step Not progressively increasing is acceptable (red) Not increasing is unsatisfactory (bold) ^ Standard SPEED — From Small To Large Gears: Steady Increase In Shaft Speed Difference — Shaft speed differences should increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one 1 difference smaller than the previous one is acceptable (red) 2 consecutive ones are a waste of possible ratios (bold) ^ K4B 050: for the 6.3 L engine M 100 of the 600 and 300 SEL 6.3 ^ W4A 018: for light-duty trucks and vans up to 5,600 kg (12,350 lb) and off-road vehicles^[B]^[C] ^ W4B 035: for medium-duty trucks up to 13,000 kg (28,660 lb)^[D]^[E] ^ Blocks S₂ ^ Blocks S₃ ^ Also BR (brake for reverse gear · German: Bremse für Rückwärtsgang) · Blocks C₁ ^ Couples S₂ with C₂ ^ Couples R₁ with S₃ ^ ^a ^b Ordinary Noted For direct determination of the gear ratio ^ ^a ^b Elementary Noted Alternative representation for determining the transmission ratio Contains only operands With simple fractions of both central gears of a planetary gearset Or with the value 1 As a basis For reliable And traceable Determination of the torque conversion ratio and efficiency

1971: W3A 040 And Follow-Up Products
— 3-Speed Transmissions With 2 Planetary Gearsets —

Layout

When the torque converter technique was fully established, 3-speed units, the W3A 040 and W3B 050 (type 722.0) is combined with V8 engines, and it uses torque converter instead of fluid coupling.^[1]^[4] The transmission saves 1 planetary gearset and uses the same housing as the 4-speed versions. The free space therefore is used to reinforce the shift elements (brakes and clutches) to handle the higher torque of the V8 engines.

First the W3A 040 was released for the all new M117 V8 engine of the W 108 and W 109 in 1971. The second in the series is the W3B 050, which was released initially for the W 116 450 SE/SEL in 1973. At that time the 4-speed transmission for the 350 SE/SEL was replaced by this 3-speed model. The reinforced W3B 050 reinforced (type 722.003) is the strongest of the series, able to handle the input of the enlarged version of the M 100, the biggest Mercedes-Benz engine in post-war history,^[7] exclusively used in the W 116 450 SEL 6.9.

Specifications

For the 3-speed models^[a] 7 main components^[b] are used, which shows economic equivalence with the direct competitor.

Gear Ratio Analysis^[c]
In-Depth Analysis^[d] With Assessment And Torque Ratio^[e] And Efficiency Calculation^[f]		Planetary Gearset: Teeth^[g]		Count	Nomi- nal^[h] Effec- tive^[i]	Cen- ter^[j]
		Simple		Count	Nomi- nal^[h] Effec- tive^[i]	Avg.^[k]

Model Type	Version First Delivery	S₁^[l] R₁^[m]	S₂^[n] R₂^[o]	Brakes Clutches	Ratio Span	Gear Step^[p]
Gear		R		1	2	3
Gear Ratio^[d]		${i_{R}}$ ^[d]		${i_{1}}$ ^[d]	${i_{2}}$ ^[d]	${i_{3}}$ ^[d]
Step^[p]		$-{\frac {i_{R}}{i_{1}}}$ ^[q]		${\frac {i_{1}}{i_{1}}}$	${\frac {i_{1}}{i_{2}}}$ ^[r]	${\frac {i_{2}}{i_{3}}}$
Δ Step^[s]^[t]					${\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}$
Shaft Speed		${\frac {i_{1}}{i_{R}}}$		${\frac {i_{1}}{i_{1}}}$	${\frac {i_{1}}{i_{2}}}$	${\frac {i_{1}}{i_{3}}}$
Δ Shaft Speed^[u]		$0-{\tfrac {i_{1}}{i_{R}}}$		${\tfrac {i_{1}}{i_{1}}}-0$	${\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}$	${\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}$
Torque Ratio^[e]		$\mu _{R}$ ^[e]		$\mu _{1}$ ^[e]	$\mu _{2}$ ^[e]	$\mu _{3}$ ^[e]
Efficiency $\eta _{n}$ ^[f]		${\frac {\mu _{R}}{i_{R}}}$ ^[f]		${\frac {\mu _{1}}{i_{1}}}$ ^[f]	${\frac {\mu _{2}}{i_{2}}}$ ^[f]	${\frac {\mu _{3}}{i_{3}}}$ ^[f]

W3A 040 722.0	40 kp⋅m (392 N⋅m; 289 lb⋅ft) 1971^[F]	44 76	35 76	3 2	2.3061 1.8361 ^[i]^[q]	1.5186
W3A 040 722.0	40 kp⋅m (392 N⋅m; 289 lb⋅ft) 1971^[F]	44 76	35 76	3 2	2.3061 1.8361 ^[i]^[q]	1.5186^[p]
Gear		R		1	2	3
Gear Ratio^[d]		−1.8361 ^[q]^[i] $-{\tfrac {1,221}{665}}$		2.3061 ${\tfrac {1,665}{722}}$	1.4605 ${\tfrac {63}{25}}$	1.0000 ${\tfrac {1}{1}}$
Step		0.7962^[q]		1.0000	1.5789	1.4605
Δ Step^[s]					1.0811
Speed		-1.2560		1.0000	1.5789	2.3061
Δ Speed		1.2560		1.0000	0.5789	0.9411
Torque Ratio^[e]		–1.7747 –1.7444		2.2747 2.2592	1.4513 1.4467	1.0000
Efficiency $\eta _{n}$ ^[f]		0.9666 0.9501		0.9864 0.9796	0.9937 0.9905	1.0000

W3A 050 722.0	50 kp⋅m (490 N⋅m; 362 lb⋅ft) 1973^[F]	44 76	35 76	3 2	2.3061 1.8361 ^[i]^[q]	1.5186
W3A 050 722.0	50 kp⋅m (490 N⋅m; 362 lb⋅ft) 1973^[F]	44 76	35 76	3 2	2.3061 1.8361 ^[i]^[q]	1.5186^[p]
Gear		R		1	2	3
Gear Ratio^[d]		−1.8361 ^[q]^[i]		2.3061	1.4605	1.0000

W3A 050 reinf.^[v] 722.0	56 kp⋅m (549 N⋅m; 405 lb⋅ft) 1975^[F]	44 76	35 76	3 2	2.3061 1.8361 ^[i]^[q]	1.5186
W3A 050 reinf.^[v] 722.0	56 kp⋅m (549 N⋅m; 405 lb⋅ft) 1975^[F]	44 76	35 76	3 2	2.3061 1.8361 ^[i]^[q]	1.5186^[p]
Gear		R		1	2	3
Gear Ratio^[d]		−1.8361 ^[q]^[i]		2.3061	1.4605	1.0000

Actuated Shift Elements
Brake B1^[w]				❶
Brake B2^[x]				❶	❶
Brake B3^[y]		❶
Clutch K1^[z]					❶	❶
Clutch K2^[aa]		❶				❶
Geometric Ratios: Speed Conversion
Gear Ratio^[d] R & 2 Ordinary^[ab] Elementary Noted^[ac]	$i_{R}=-{\frac {S_{1}(S_{2}+R_{2})}{R_{1}S_{2}}}$			$i_{2}={\frac {S_{2}+R_{2}}{R_{2}}}$
Gear Ratio^[d] R & 2 Ordinary^[ab] Elementary Noted^[ac]	$i_{R}=-{\tfrac {S_{1}}{R_{1}}}(1+{\tfrac {R_{2}}{S_{2}}})$			$i_{2}=1+{\tfrac {S_{2}}{R_{2}}}$

Gear Ratio^[d] 1 & 3 Ordinary^[ab] Elementary Noted^[ac]	$i_{1}={\frac {(S_{1}+R_{1})(S_{2}+R_{2})}{R_{1}R_{2}}}$				$i_{3}={\frac {1}{1}}$
Gear Ratio^[d] 1 & 3 Ordinary^[ab] Elementary Noted^[ac]	$i_{1}=\left(1+{\tfrac {S_{1}}{R_{1}}}\right)\left(1+{\tfrac {S_{2}}{R_{2}}}\right)$				$i_{3}={\frac {1}{1}}$
Kinetic Ratios: Torque Conversion
Torque Ratio^[e] R & 2	$\mu _{R}=-{\tfrac {S_{1}}{R_{1}}}\eta _{0}(1+{\tfrac {R_{2}}{S_{2}}}\eta _{0})$			$\mu _{2}=1+{\tfrac {S_{2}}{R_{2}}}\eta _{0}$

Torque Ratio^[e] 1 & 3	$\mu _{1}=\left(1+{\tfrac {S_{1}}{R_{1}}}\eta _{0}\right)\left(1+{\tfrac {S_{2}}{R_{2}}}\eta _{0}\right)$				$\mu _{3}={\frac {1}{1}}$

^ plus 1 reverse gear ^ 2 simple planetary gearsets,^[4] 3 brakes, 2 clutches ^ Revised 14 January 2026 Nomenclature $S_{n}=$ sun gear: number of teeth $R_{n}=$ ring gear: number of teeth $\color {gray}{C_{n}=}$ carrier or planetary gear carrier (not needed) $s_{n}=$ sun gear: shaft speed $r_{n}=$ ring gear: shaft speed $c_{n}=$ carrier or planetary gear carrier: shaft speed With $n=$ gear is $i_{n}=$ gear ratio or transmission ratio $\omega _{1;n}=\omega _{t}=$ shaft speed shaft 1: input (turbine) shaft $\omega _{2;n}=$ shaft speed shaft 2: output shaft $T_{1;n}=T_{t}=$ torque shaft 1: input (turbine) shaft $T_{2;n}=$ torque shaft 2: output shaft $\mu _{n}=$ torque ratio or torque conversion ratio $\eta _{n}=$ efficiency $i_{0}=$ stationary gear ratio $\eta _{0}=$ (assumed) stationary gear efficiency ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Gear Ratio (Transmission Ratio) $i_{n}$ — Speed Conversion — The gear ratio $i_{n}$ is the ratio of input shaft speed $\omega _{1;n}$ to output shaft speed $\omega _{2;n}$ and therefore corresponds to the reciprocal of the shaft speeds $i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}$ ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Torque Ratio (Torque Conversion Ratio) $\mu _{n}$ — Torque Conversion — The torque ratio $\mu _{n}$ is the ratio of output torque $T_{2;n}$ to input torque $T_{1;n}$ minus efficiency losses and therefore corresponds (apart from the efficiency losses) to the reciprocal of the shaft speeds too $\mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}$ whereby $\eta _{n;\eta _{0}}$ may vary from gear to gear according to the formulas listed in this table and $0\leq \eta _{n;\eta _{0}}\leq 1$ ^ ^a ^b ^c ^d ^e ^f ^g Efficiency The efficiency $\eta _{n}$ is calculated from the torque ratio in relation to the gear ratio (transmission ratio) $\eta _{n}={\frac {\mu _{n}}{i_{n}}}$ Power loss for single meshing gears is in the range of 1 % to 1.5 % helical gear pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range Corridor for torque ratio and efficiency in planetary gearsets, the stationary gear ratio $i_{0}$ is formed via the planetary gears and thus by two meshes for reasons of simplification, the efficiency for both meshes together is commonly specified there the efficiencies $\eta _{0}$ specified here are based on assumed efficiencies for the stationary ratio $i_{0}$ of $\eta _{0}=0.9800$ (upper value) and $\eta _{0}=0.9700$ (lower value) for both interventions together The corresponding efficiency for single-meshing gear pairs is ${\eta _{0}}^{\tfrac {1}{2}}$ at $0.9800^{\tfrac {1}{2}}=0.98995$ (upper value) and $0.9700^{\tfrac {1}{2}}=0.98489$ (lower value) ^ Layout Input and output are on opposite sides Planetary gearset 1 is on the input (turbine) side Input (turbine) shaft is R₁ Output shaft is C₂ ^ Total Ratio Span (Total Gear/Transmission Ratio) Nominal ${\frac {\omega _{2;n}}{\omega _{2;1}}}={\frac {\frac {\omega _{2;n}}{\omega _{2;1}\omega _{2;n}}}{\frac {\omega _{2;1}}{\omega _{2;1}\omega _{2;n}}}}={\frac {\frac {1}{\omega _{2;1}}}{\frac {1}{\omega _{2;n}}}}={\frac {\frac {\omega _{t}}{\omega _{2;1}}}{\frac {\omega _{t}}{\omega _{2;n}}}}={\frac {i_{1}}{i_{n}}}$ A wider span enables the downspeeding when driving outside the city limits increase the climbing ability when driving over mountain passes or off-road or when towing a trailer ^ ^a ^b ^c ^d ^e ^f ^g Total Ratio Span (Total Gear Ratio/Total Transmission Ratio) Effective ${\frac {\omega _{2;n}}{max(\omega _{2;1};\|\omega _{2;R}\|)}}={\frac {min(i_{1};\|i_{R}\|)}{i_{n}}}$ The span is only effective to the extent that the reverse gear ratio matches that of 1st gear see also Standard R:1 Digression Reverse gear is usually longer than 1st gear the effective span* is therefore of central importance for describing the suitability of a transmission* because in these cases, the nominal spread conveys a misleading picture which is only unproblematic for vehicles with high specific power Market participants Manufacturers naturally have no interest in specifying the effective span Users have not yet formulated the practical benefits that the effective span has for them The effective span has not yet played a role in research and teaching Contrary to its significance the effective span* has therefore not yet been able to establish itself* either in theory or in practice. End of digression ^ Ratio Span's Center $(i_{1}i_{n})^{\frac {1}{2}}$ The center indicates the speed level of the transmission Together with the final drive ratio it gives the shaft speed level of the vehicle ^ Average Gear Step $\left({\frac {\omega _{2;n}}{\omega _{2;1}}}\right)^{\frac {1}{n-1}}=\left({\frac {i_{1}}{i_{n}}}\right)^{\frac {1}{n-1}}$ There are $n-1$ gear steps between $n$ gears with decreasing step width the gears connect better to each other shifting comfort increases ^ Sun 1: sun gear of gearset 1 ^ Ring 1: ring gear of gearset 1 ^ Sun 2: sun gear of gearset 2 ^ Ring 2: ring gear of gearset 2 ^ ^a ^b ^c ^d ^e Standard 50:50 — 50 % Is Above And 50 % Is Below The Average Gear Step — With steadily decreasing gear steps (yellow highlighted line Step) and a particularly large step from 1st to 2nd gear the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger and the upper half of the gear steps (between the large gears; rounded up, here the last 1) is always smaller than the average gear step (cell highlighted yellow two rows above on the far right) lower half: smaller gear steps are a waste of possible ratios (red bold) upper half: larger gear steps are unsatisfactory (red bold) ^ ^a ^b ^c ^d ^e ^f ^g ^h Standard R:1 — Reverse And 1st Gear Have The Same Ratio — The ideal reverse gear has the same transmission ratio as 1st gear no impairment when maneuvering especially when towing a trailer a torque converter can only partially compensate for this deficiency Plus 11.11 % minus 10 % compared to 1st gear is good Plus 25 % minus 20 % is acceptable (red) Above this is unsatisfactory (bold) ^ Standard 1:2 — Gear Step 1st To 2nd Gear As Small As Possible — With continuously decreasing gear steps (yellow marked line Step) the largest gear step is the one from 1st to 2nd gear, which for a good speed connection and a smooth gear shift must be as small as possible A gear ratio of up to 1.6667 : 1 (5 : 3) is good Up to 1.7500 : 1 (7 : 4) is acceptable (red) Above is unsatisfactory (bold) ^ ^a ^b From large to small gears (from right to left) ^ Standard STEP — From Large To Small Gears: Steady And Progressive Increase In Gear Steps — Gear steps should increase: Δ Step (first green highlighted line Δ Step) is always greater than 1 As progressive as possible: Δ Step is always greater than the previous step Not progressively increasing is acceptable (red) Not increasing is unsatisfactory (bold) ^ Standard SPEED — From Small To Large Gears: Steady Increase In Shaft Speed Difference — Shaft speed differences should increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one 1 difference smaller than the previous one is acceptable (red) 2 consecutive ones are a waste of possible ratios (bold) ^ W3A 050 reinforced: for the 6.8 L engine M 100 of the 450 SEL 6.9 ^ Blocks S₁ ^ Blocks S₂ ^ Blocks C₁ ^ Couples S₁ with C₁ ^ Couples S₁ with S₂ ^ ^a ^b Ordinary Noted For direct determination of the gear ratio ^ ^a ^b Elementary Noted Alternative representation for determining the transmission ratio Contains only operands With simple fractions of both central gears of a planetary gearset Or with the value 1 As a basis For reliable And traceable Determination of the torque conversoin ratio and efficiency

Applications

K4A 025

1961–1965 (saloon) · 1961–1968 (coupé/convertible) W 111
1961–1965 (saloon) · 1962–1968 (coupé/convertible) W 112
1961–1968 W 110
1963–1971 W 113
1965–1968 W 108/W 109

K4B 050

1964–1981 600 (W 100)
1968–1972 300 SEL 6.3 (W 109)

K4C 025

1968–1971 (coupé/convertible) W 111
1968–1972 W 108/W 109

W 114/W 115
Chassis code	Car model	Engine code	Transmission code
114.015 and 114.615	230.6	180.954	722.203
114.017 and 114.617	230.6 Lang	180.954	722.203
114.011 and 114.611	250	130.923	722.204
114.023 and 114.623	250 C	130.923	722.204
114.060 and 114.660	280	110.921	722.202
114.073 and 114.673	280 C	110.921	722.202
114.062 and 114.662	280 E	110.981	722.200
114.072 and 114.672	280 CE	110.981	722.200
115.015 and 115.615	200	115.923	722.205
115.010	220	115.920	722.205
115.115 and 115.715	200 D	615.913	722.206
115.110 and 115.710	220 D	615.912
115.112	220 D Lang	615.912

K4A 040

W 108/W 109
Chassis code	Car model	Engine code	Transmission code	Notes
109.057	300 SEL 3.5	3.5 L M 116 V8	722.201	worldwide except USA
108.067	280 SE 3.5
108.068	280 SEL 3.5

R 107/C 107
Chassis code	Car model	Engine code	Transmission code
107.043	350 SL	116.982 (D-Jet) 116.984 (K-Jet)	722.201
107.023	350 SLC	116.982 (D-Jet) 116.984 (K-Jet)	722.201

W3A 040

W 108/W 109
Chassis code	Car model	Engine code	Transmission code	Notes
109.056	300 SEL 4.5	4.5 L M 117 V8	722.000	USA only
108.057	280 SE 4.5
108.058	280 SEL 4.5

R 107/C 107
Chassis code	Car model	Engine code	Transmission code	Notes
107.043	350 SL	116.982 (D-Jet) 116.984 (K-Jet)	722.002
107.023	350 SLC	116.982 (D-Jet) 116.984 (K-Jet)	722.002
107.044	450 SL	117.982 (D-Jet) 117.985 (K-Jet)	722.004	USA and Japan only
107.024	450 SLC	117.982 (D-Jet) 117.985 (K-Jet)	722.004	USA and Japan only

W 116
Chassis code	Car model	Engine code	Transmission code	Notes
116.028	350 SE	116.983 (D-Jet) 116.985 (K-Jet)	722.002
116.029	350 SEL	116.983 (D-Jet) 116.985 (K-Jet)	722.002
116.032	450 SE	117.983 (D-Jet) 117.986 (K-Jet)	722.004	USA and Japan only
116.033	450 SEL	117.983 (D-Jet) 117.986 (K-Jet)	722.004	USA and Japan only

W3B 050

R 107/C 107
Chassis code	Car model	Engine code	Transmission code	Notes
107.044	450 SL	117.982 (D-Jet) 117.985 (K-Jet)	722.001	worldwide except USA and Japan
107.024	450 SLC	117.982 (D-Jet) 117.985 (K-Jet)	722.001	worldwide except USA and Japan

W 116
Chassis code	Car model	Engine code	Transmission code	Notes
116.032	450 SE	117.983 (D-Jet) 117.986 (K-Jet)	722.001	worldwide except USA and Japan
116.033	450 SEL	117.983 (D-Jet) 117.986 (K-Jet)	722.001	worldwide except USA and Japan
116.036	450 SEL 6.9	100.985	722.003	722.003 W3B 050 reinforced^[8]

1977 – 1984 Porsche 928

W4B 025

R 107/C 107
Chassis code	Car model	Engine code	Transmission code
107.042	280 SL	110.982 110.986 110.990	722.103 722.112
107.022	280 SLC	110.982 110.986	722.103 722.112

W 114/W 115
Chassis code	Car model	Engine code	Transmission code
114.015 and 114.615	230.6	180.954	722.105
114.017 and 114.617	230.6 Lang	180.954	722.105
114.011 and 114.611	250	130.923	722.104
114.023 and 114.623	250 C	130.923	722.104
114.060 and 114.660	280	110.921	722.102
114.073 and 114.673	280 C	110.921	722.102
114.062 and 114.662	280 E	110.981	722.103
114.072 and 114.672	280 CE	110.981	722.103
115.015 and 115.615	200	115.923	722.106
115.017	230.4	115.951	722.110
115.115 and 115.715	200 D	615.913	722.107
115.110 and 115.710	220 D	615.912
115.112	220 D Lang	615.912
115.117	240 D	616.916	722.108
115.119	240 D Lang	616.916	722.108
115.114	240 D 3.0	617.910	722.109

W 116
Chassis code	Car model	Engine code	Transmission code	Notes
116.020	280 S	110.922	722.100 722.102 722.111
116.024	280 SE	110.983 (D-Jet) 110.985 (K-Jet)	722.101 722.103 722.112
116.025	280 SEL	110.983 (D-Jet) 110.985 (K-Jet)	722.101 722.103 722.112
116.120	300 SD	617.950	722.120	USA only

W 123
Chassis code	Car model	Engine code	Transmission code	Notes
123.020	200	115.938 115.939	722.115
123.220	200	102.920 102.939	722.121
123.280	200 T	102.920 102.939	722.121
123.023	230	115.954	722.119
123.083	230 T
123.043	230 C
123.223	230 E	102.980	722.122
123.283	230 TE
123.243	230 CE
123.026	250	123.920 123.921	722.113
123.086	250 T
123.028	250 Lang
123.030	280	110.923	722.111
123.050	280 C	110.923	722.111
123.033	280 E	110.984 110.988	722.112
123.093	280 TE
123.053	280 CE
123.120	200 D	615.940	722.116
123.126	220 D	615.941	722.116
123.123	240 D	616.912	722.117
123.183	240 TD
123.125	240 D Lang
123.130	300 D	617.912	722.118
123.190	300 TD
123.132	300 D Lang
123.150	300 CD			USA only

Notes

^ ^a ^b pp. 6 & 20^[3]
^ ^a ^b ^c ^d ^e ^f ^g pp. 7 & 20^[3]
^ ^a ^b ^c p. 487^[5]
^ ^a ^b ^c pp. 9 & 22^[3]
^ ^a ^b ^c p. 489^[5]
^ ^a ^b ^c p. 452^[5]

References

^ ^a ^b "50 years of automatic transmissions from Mercedes-Benz".
^ ^a ^b Johannes Looman · Gear Transmissions · pp. 133 ff · German: Johannes Looman · Zahnradgetriebe · Berlin und Heidelberg 1970 · Print ISBN 978-3-540-04894-7 · S. 133 ff
^ ^a ^b ^c Result And Outlook · commemorative publication for Prof. Dr. Hans-Joachim Foerster on the occasion of leaving as director from active duty at Daimler-Benz AG · November 1982 · German: Ergebnis und Ausblick · Festschrift für Herrn Prof. Dr. Hans-Joachim Förster zum Ausscheiden als Direktor aus dem aktiven Dienst der Daimler-Benz AG · November 1982
^ ^a ^b ^c ^d ^e "MB Passenger Car Series 116" (PDF). · p. 10
^ ^a ^b ^c Hans-Joachim Foerster · Automatic Vehicle Transmissions · German: Hans-Joachim Förster · Automatische Fahrzeuggetriebe · Berlin und Heidelberg 1991 · Print ISBN 978-3-642-84119-4 · eBook ISBN 978-3-642-84118-7
^ "MB Passenger Car Series 116" (PDF). p. 11
^ Only surpassed by the Mercedes-Benz 770, built from 1930 to 1943
^ "MB AUS 1979" (PDF). · p. 57

[2] Differences in gear ratios have a measurable, direct impact on vehicle dynamics, performance, waste emissions as well as fuel mileage

[Forward-3] ^ ^a ^b ^c ^d ^e ^f ^g Forward gears only

[Fluid_Coupling-7] Fluid coupling · German: Kupplung or Flüssigkeitskupplung

[8] K4B 050: for the 6.3 L engine M 100 of the 600 and 300 SEL 6.3

[9] Unveiled in September 1963 at the International Motor Show in Frankfurt, it went into production in September 1964

[Torque_Converter-11] Torque converter · German: Wandler or Drehmomentwandler

[15] W4A 018: for light-duty trucks and vans up to 5,600 kg (12,350 lb) and off-road vehicles^[B]^[C]

[18] W4B 035: for medium-duty trucks up to 13,000 kg (28,660 lb)^[D]^[E]

[19] W3A 050 reinforced: for the 6.8 L engine M 100 of the 450 SEL 6.9

[20] us 1 reverse gear

[21] 2 simple planetary gearsets, 3 brakes, 3 clutches

[22] Revised 14 January 2026
Nomenclature
$S_{n}=$ sun gear: number of teeth

$R_{n}=$ ring gear: number of teeth

$\color {gray}{C_{n}=}$ carrier or planetary gear carrier (not needed)

$s_{n}=$ sun gear: shaft speed

$r_{n}=$ ring gear: shaft speed

$c_{n}=$ carrier or planetary gear carrier: shaft speed
With $n=$ gear is
$i_{n}=$ gear ratio or transmission ratio

$\omega _{1;n}=\omega _{t}=$ shaft speed shaft 1: input (turbine) shaft

$\omega _{2;n}=$ shaft speed shaft 2: output shaft

$T_{1;n}=T_{t}=$ torque shaft 1: input (turbine) shaft

$T_{2;n}=$ torque shaft 2: output shaft

$\mu _{n}=$ torque ratio or torque conversion ratio

$\eta _{n}=$ efficiency

$i_{0}=$ stationary gear ratio

$\eta _{0}=$ (assumed) stationary gear efficiency

[13] $S_{n}=$ sun gear: number of teeth

[14] $R_{n}=$ ring gear: number of teeth

[15] $\color {gray}{C_{n}=}$ carrier or planetary gear carrier (not needed)

[16] $s_{n}=$ sun gear: shaft speed

[17] $r_{n}=$ ring gear: shaft speed

[18] $c_{n}=$ carrier or planetary gear carrier: shaft speed

[19] $i_{n}=$ gear ratio or transmission ratio

[20] $\omega _{1;n}=\omega _{t}=$ shaft speed shaft 1: input (turbine) shaft

[21] $\omega _{2;n}=$ shaft speed shaft 2: output shaft

[22] $T_{1;n}=T_{t}=$ torque shaft 1: input (turbine) shaft

[23] $T_{2;n}=$ torque shaft 2: output shaft

[24] $\mu _{n}=$ torque ratio or torque conversion ratio

[25] $\eta _{n}=$ efficiency

[26] $i_{0}=$ stationary gear ratio

[27] $\eta _{0}=$ (assumed) stationary gear efficiency

[Gear_Ratio-23] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Gear Ratio (Transmission Ratio) $i_{n}$
— Speed Conversion —
The gear ratio $i_{n}$ is the ratio of
input shaft speed $\omega _{1;n}$

to output shaft speed $\omega _{2;n}$

and therefore corresponds to the reciprocal of the shaft speeds
$i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}$

[29] The gear ratio $i_{n}$ is the ratio of
input shaft speed $\omega _{1;n}$

to output shaft speed $\omega _{2;n}$

[30] ut shaft speed $\omega _{1;n}$

[31] to output shaft speed $\omega _{2;n}$

[32] therefore corresponds to the reciprocal of the shaft speeds
$i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}$

[33] $i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}$

[Torque_Ratio-24] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Torque Ratio (Torque Conversion Ratio) $\mu _{n}$
— Torque Conversion —
The torque ratio $\mu _{n}$ is the ratio of
output torque $T_{2;n}$

to input torque $T_{1;n}$

minus efficiency losses

and therefore corresponds (apart from the efficiency losses) to the reciprocal of the shaft speeds too
$\mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}$

whereby $\eta _{n;\eta _{0}}$ may vary from gear to gear according to the formulas listed in this table and $0\leq \eta _{n;\eta _{0}}\leq 1$

[35] The torque ratio $\mu _{n}$ is the ratio of
output torque $T_{2;n}$

to input torque $T_{1;n}$

minus efficiency losses

[36] utput torque $T_{2;n}$

[37] to input torque $T_{1;n}$

[38] us efficiency losses

[39] therefore corresponds (apart from the efficiency losses) to the reciprocal of the shaft speeds too
$\mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}$

whereby $\eta _{n;\eta _{0}}$ may vary from gear to gear according to the formulas listed in this table and $0\leq \eta _{n;\eta _{0}}\leq 1$

[40] $\mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}$

[41] whereby $\eta _{n;\eta _{0}}$ may vary from gear to gear according to the formulas listed in this table and $0\leq \eta _{n;\eta _{0}}\leq 1$

[Efficiency-25] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Efficiency
The efficiency $\eta _{n}$ is calculated
from the torque ratio

in relation to the gear ratio (transmission ratio)

$\eta _{n}={\frac {\mu _{n}}{i_{n}}}$

Power loss for single meshing gears
is in the range of 1 % to 1.5 %

helical gear pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range

spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range
Corridor for torque ratio and efficiency
in planetary gearsets, the stationary gear ratio $i_{0}$ is formed via the planetary gears and thus by two meshes

for reasons of simplification, the efficiency for both meshes together is commonly specified there

the efficiencies $\eta _{0}$ specified here are based on assumed efficiencies for the stationary ratio $i_{0}$
of $\eta _{0}=0.9800$ (upper value)

and $\eta _{0}=0.9700$ (lower value)

for both interventions together

The corresponding efficiency
for single-meshing gear pairs is ${\eta _{0}}^{\tfrac {1}{2}}$

at $0.9800^{\tfrac {1}{2}}=0.98995$ (upper value)

and $0.9700^{\tfrac {1}{2}}=0.98489$ (lower value)

[43] The efficiency $\eta _{n}$ is calculated
from the torque ratio

in relation to the gear ratio (transmission ratio)

$\eta _{n}={\frac {\mu _{n}}{i_{n}}}$

[44] rom the torque ratio

[45] relation to the gear ratio (transmission ratio)

[46] $\eta _{n}={\frac {\mu _{n}}{i_{n}}}$

[47] Power loss for single meshing gears
is in the range of 1 % to 1.5 %

helical gear pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range

spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range

[48] s in the range of 1 % to 1.5 %

[49] r pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range

[50] spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range

[51] tary gearsets, the stationary gear ratio $i_{0}$ is formed via the planetary gears and thus by two meshes

[52] r reasons of simplification, the efficiency for both meshes together is commonly specified there

[53] the efficiencies $\eta _{0}$ specified here are based on assumed efficiencies for the stationary ratio $i_{0}$
of $\eta _{0}=0.9800$ (upper value)

and $\eta _{0}=0.9700$ (lower value)

[54] $\eta _{0}=0.9800$ (upper value)

[55] $\eta _{0}=0.9700$ (lower value)

[56] r both interventions together

[57] The corresponding efficiency
for single-meshing gear pairs is ${\eta _{0}}^{\tfrac {1}{2}}$

at $0.9800^{\tfrac {1}{2}}=0.98995$ (upper value)

and $0.9700^{\tfrac {1}{2}}=0.98489$ (lower value)

[58] r single-meshing gear pairs is ${\eta _{0}}^{\tfrac {1}{2}}$

[59] t $0.9800^{\tfrac {1}{2}}=0.98995$ (upper value)

[60] $0.9700^{\tfrac {1}{2}}=0.98489$ (lower value)

[26] Layout
Input and output are on opposite sides

Planetary gearset 1 is on the input (turbine) side

Input shafts is S₁ and, if actuated, C₁

Output shaft is C₂

[62] Input and output are on opposite sides

[63] Planetary gearset 1 is on the input (turbine) side

[64] Input shafts is S₁ and, if actuated, C₁

[65] Output shaft is C₂

[27] Total Ratio Span (Total Gear/Transmission Ratio) Nominal
${\frac {\omega _{2;n}}{\omega _{2;1}}}={\frac {\frac {\omega _{2;n}}{\omega _{2;1}\omega _{2;n}}}{\frac {\omega _{2;1}}{\omega _{2;1}\omega _{2;n}}}}={\frac {\frac {1}{\omega _{2;1}}}{\frac {1}{\omega _{2;n}}}}={\frac {\frac {\omega _{t}}{\omega _{2;1}}}{\frac {\omega _{t}}{\omega _{2;n}}}}={\frac {i_{1}}{i_{n}}}$

A wider span enables the
downspeeding when driving outside the city limits

increase the climbing ability
when driving over mountain passes or off-road

or when towing a trailer

[67] ${\frac {\omega _{2;n}}{\omega _{2;1}}}={\frac {\frac {\omega _{2;n}}{\omega _{2;1}\omega _{2;n}}}{\frac {\omega _{2;1}}{\omega _{2;1}\omega _{2;n}}}}={\frac {\frac {1}{\omega _{2;1}}}{\frac {1}{\omega _{2;n}}}}={\frac {\frac {\omega _{t}}{\omega _{2;1}}}{\frac {\omega _{t}}{\omega _{2;n}}}}={\frac {i_{1}}{i_{n}}}$

[68] A wider span enables the
downspeeding when driving outside the city limits

increase the climbing ability
when driving over mountain passes or off-road

or when towing a trailer

[69] wnspeeding when driving outside the city limits

[70] rease the climbing ability
when driving over mountain passes or off-road

or when towing a trailer

[71] when driving over mountain passes or off-road

[72] r when towing a trailer

[effective-28] Total Ratio Span (Total Gear Ratio/Total Transmission Ratio) Effective
${\frac {\omega _{2;n}}{max(\omega _{2;1};|\omega _{2;R}|)}}={\frac {min(i_{1};|i_{R}|)}{i_{n}}}$

The span is only effective to the extent that
the reverse gear ratio

matches that of 1st gear

see also Standard R:1
Digression
Reverse gear
is usually longer than 1st gear

the effective span is therefore of central importance for describing the suitability of a transmission

because in these cases, the nominal spread conveys a misleading picture

which is only unproblematic for vehicles with high specific power
Market participants
Manufacturers naturally have no interest in specifying the effective span

Users have not yet formulated the practical benefits that the effective span has for them

The effective span has not yet played a role in research and teaching
Contrary to its significance
the effective span has therefore not yet been able to establish itself
either in theory

or in practice.
End of digression

[74] ${\frac {\omega _{2;n}}{max(\omega _{2;1};|\omega _{2;R}|)}}={\frac {min(i_{1};|i_{R}|)}{i_{n}}}$

[75] The span is only effective to the extent that
the reverse gear ratio

matches that of 1st gear

[76] the reverse gear ratio

[77] tches that of 1st gear

[78] see also Standard R:1

[79] s usually longer than 1st gear

[80] the effective span is therefore of central importance for describing the suitability of a transmission

[81] use in these cases, the nominal spread conveys a misleading picture

[82] which is only unproblematic for vehicles with high specific power

[83] Manufacturers naturally have no interest in specifying the effective span

[84] Users have not yet formulated the practical benefits that the effective span has for them

[85] The effective span has not yet played a role in research and teaching

[86] the effective span has therefore not yet been able to establish itself
either in theory

or in practice.

[87] ther in theory

[88] r in practice.

[29] Ratio Span's Center
$(i_{1}i_{n})^{\frac {1}{2}}$

The center indicates the speed level of the transmission

Together with the final drive ratio

it gives the shaft speed level of the vehicle

[90] $(i_{1}i_{n})^{\frac {1}{2}}$

[91] The center indicates the speed level of the transmission

[92] Together with the final drive ratio

[93] t gives the shaft speed level of the vehicle

[30] Average Gear Step
$\left({\frac {\omega _{2;n}}{\omega _{2;1}}}\right)^{\frac {1}{n-1}}=\left({\frac {i_{1}}{i_{n}}}\right)^{\frac {1}{n-1}}$

There are $n-1$ gear steps between $n$ gears

with decreasing step width
the gears connect better to each other

shifting comfort increases

[95] $\left({\frac {\omega _{2;n}}{\omega _{2;1}}}\right)^{\frac {1}{n-1}}=\left({\frac {i_{1}}{i_{n}}}\right)^{\frac {1}{n-1}}$

[96] There are $n-1$ gear steps between $n$ gears

[97] with decreasing step width
the gears connect better to each other

shifting comfort increases

[98] the gears connect better to each other

[99] shifting comfort increases

[31] Sun 1: sun gear of gearset 1

[32] Ring 1: ring gear of gearset 1

[33] Sun 2: sun gear of gearset 2

[34] Ring 2: ring gear of gearset 2

[50:50-35] ^ ^a ^b ^c ^d ^e ^f ^g Standard 50:50
— 50 % Is Above And 50 % Is Below The Average Gear Step —
With steadily decreasing gear steps (yellow highlighted line Step)

and a particularly large step from 1st to 2nd gear
the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger

and the upper half of the gear steps (between the large gears; rounded up, here the last 2) is always smaller

than the average gear step (cell highlighted yellow two rows above on the far right)

lower half: smaller gear steps are a waste of possible ratios (red bold)

upper half: larger gear steps are unsatisfactory (red bold)

[105] With steadily decreasing gear steps (yellow highlighted line Step)

[106] rticularly large step from 1st to 2nd gear
the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger

and the upper half of the gear steps (between the large gears; rounded up, here the last 2) is always smaller

[107] the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger

[108] the upper half of the gear steps (between the large gears; rounded up, here the last 2) is always smaller

[109] than the average gear step (cell highlighted yellow two rows above on the far right)

[110] wer half: smaller gear steps are a waste of possible ratios (red bold)

[111] upper half: larger gear steps are unsatisfactory (red bold)

[R:1-36] Standard R:1
— Reverse And 1st Gear Have The Same Ratio —
The ideal reverse gear has the same transmission ratio as 1st gear
no impairment when maneuvering

especially when towing a trailer

a torque converter can only partially compensate for this deficiency

Plus 11.11 % minus 10 % compared to 1st gear is good

Plus 25 % minus 20 % is acceptable (red)

Above this is unsatisfactory (bold)

[113] The ideal reverse gear has the same transmission ratio as 1st gear
no impairment when maneuvering

especially when towing a trailer

a torque converter can only partially compensate for this deficiency

[114] rment when maneuvering

[115] specially when towing a trailer

[116] torque converter can only partially compensate for this deficiency

[117] Plus 11.11 % minus 10 % compared to 1st gear is good

[118] Plus 25 % minus 20 % is acceptable (red)

[119] Above this is unsatisfactory (bold)

[1:2-37] Standard 1:2
— Gear Step 1st To 2nd Gear As Small As Possible —
With continuously decreasing gear steps (yellow marked line Step)

the largest gear step is the one from 1st to 2nd gear, which
for a good speed connection and

a smooth gear shift

must be as small as possible
A gear ratio of up to 1.6667:1 (5:3) is good

Up to 1.7500:1 (7:4) is acceptable (red)

Above is unsatisfactory (bold)

[121] With continuously decreasing gear steps (yellow marked line Step)

[122] the largest gear step is the one from 1st to 2nd gear, which
for a good speed connection and

a smooth gear shift

[123] r a good speed connection and

[124] smooth gear shift

[125] ust be as small as possible
A gear ratio of up to 1.6667:1 (5:3) is good

Up to 1.7500:1 (7:4) is acceptable (red)

Above is unsatisfactory (bold)

[126] A gear ratio of up to 1.6667:1 (5:3) is good

[127] Up to 1.7500:1 (7:4) is acceptable (red)

[128] Above is unsatisfactory (bold)

[LS-38] From large to small gears (from right to left)

[step-39] Standard STEP
— From Large To Small Gears: Steady And Progressive Increase In Gear Steps —
Gear steps should
increase: Δ Step (first green highlighted line Δ Step) is always greater than 1

As progressive as possible: Δ Step is always greater than the previous step

Not progressively increasing is acceptable (red)

Not increasing is unsatisfactory (bold)

[131] Gear steps should
increase: Δ Step (first green highlighted line Δ Step) is always greater than 1

As progressive as possible: Δ Step is always greater than the previous step

[132] increase: Δ Step (first green highlighted line Δ Step) is always greater than 1

[133] As progressive as possible: Δ Step is always greater than the previous step

[134] Not progressively increasing is acceptable (red)

[135] Not increasing is unsatisfactory (bold)

[speed-40] Standard SPEED
— From Small To Large Gears: Steady Increase In Shaft Speed Difference —
Shaft speed differences should
increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one

1 difference smaller than the previous one is acceptable (red)

2 consecutive ones are a waste of possible ratios (bold)

[137] Shaft speed differences should
increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one

[138] increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one

[139] 1 difference smaller than the previous one is acceptable (red)

[140] 2 consecutive ones are a waste of possible ratios (bold)

[41] Blocks R₁

[42] Blocks S₂

[43] Also BR (brake for reverse gear · German: Bremse für Rückwärtsgang) · blocks C₁ and R₂

[44] Couples C₁ and R₂ with the input (turbine)

[45] Couples C₁ and R₂ with S₂

[46] Also KR (clutch for reverse gear · German: Kupplung für Rückwärtsgang) · couples R₁ with S₂

[ordinary-47] Ordinary Noted
For direct determination of the gear ratio

[148] For direct determination of the gear ratio

[elementary-48] Elementary Noted
Alternative representation for determining the transmission ratio

Contains only operands
With simple fractions of both central gears of a planetary gearset

Or with the value 1

As a basis
For reliable

And traceable

Determination of the torque conversion ratio and efficiency

[150] Alternative representation for determining the transmission ratio

[151] Contains only operands
With simple fractions of both central gears of a planetary gearset

Or with the value 1

[152] With simple fractions of both central gears of a planetary gearset

[153] Or with the value 1

[154] As a basis
For reliable

And traceable

[155] For reliable

[156] And traceable

[157] Determination of the torque conversion ratio and efficiency

[50] us 1 reverse gear

[51] 3 simple planetary gearsets, 3 brakes, 2 clutches

[52] Revised 14 January 2026
Nomenclature
$S_{n}=$ sun gear: number of teeth

$R_{n}=$ ring gear: number of teeth

$\color {gray}{C_{n}=}$ carrier or planetary gear carrier (not needed)

$s_{n}=$ sun gear: shaft speed

$r_{n}=$ ring gear: shaft speed

$c_{n}=$ carrier or planetary gear carrier: shaft speed
With $n=$ gear is
$i_{n}=$ gear ratio or transmission ratio

$\omega _{1;n}=\omega _{t}=$ shaft speed shaft 1: input (turbine) shaft

$\omega _{2;n}=$ shaft speed shaft 2: output shaft

$T_{1;n}=T_{t}=$ torque shaft 1: input (turbine) shaft

$T_{2;n}=$ torque shaft 2: output shaft

$\mu _{n}=$ torque ratio or torque conversion ratio

$\eta _{n}=$ efficiency

$i_{0}=$ stationary gear ratio

$\eta _{0}=$ (assumed) stationary gear efficiency

[161] $S_{n}=$ sun gear: number of teeth

[162] $R_{n}=$ ring gear: number of teeth

[163] $\color {gray}{C_{n}=}$ carrier or planetary gear carrier (not needed)

[164] $s_{n}=$ sun gear: shaft speed

[165] $r_{n}=$ ring gear: shaft speed

[166] $c_{n}=$ carrier or planetary gear carrier: shaft speed

[167] $i_{n}=$ gear ratio or transmission ratio

[168] $\omega _{1;n}=\omega _{t}=$ shaft speed shaft 1: input (turbine) shaft

[169] $\omega _{2;n}=$ shaft speed shaft 2: output shaft

[170] $T_{1;n}=T_{t}=$ torque shaft 1: input (turbine) shaft

[171] $T_{2;n}=$ torque shaft 2: output shaft

[172] $\mu _{n}=$ torque ratio or torque conversion ratio

[173] $\eta _{n}=$ efficiency

[174] $i_{0}=$ stationary gear ratio

[175] $\eta _{0}=$ (assumed) stationary gear efficiency

[Gear_Ratio-53] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o Gear Ratio (Transmission Ratio) $i_{n}$
— Speed Conversion —
The gear ratio $i_{n}$ is the ratio of
input shaft speed $\omega _{1;n}$

to output shaft speed $\omega _{2;n}$

and therefore corresponds to the reciprocal of the shaft speeds
$i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}$

[177] The gear ratio $i_{n}$ is the ratio of
input shaft speed $\omega _{1;n}$

to output shaft speed $\omega _{2;n}$

[178] ut shaft speed $\omega _{1;n}$

[179] to output shaft speed $\omega _{2;n}$

[180] therefore corresponds to the reciprocal of the shaft speeds
$i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}$

[181] $i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}$

[Torque_Ratio-54] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Torque Ratio (Torque Conversion Ratio) $\mu _{n}$
— Torque Conversion —
The torque ratio $\mu _{n}$ is the ratio of
output torque $T_{2;n}$

to input torque $T_{1;n}$

minus efficiency losses

and therefore corresponds (apart from the efficiency losses) to the reciprocal of the shaft speeds too
$\mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}$

whereby $\eta _{n;\eta _{0}}$ may vary from gear to gear according to the formulas listed in this table and $0\leq \eta _{n;\eta _{0}}\leq 1$

[183] The torque ratio $\mu _{n}$ is the ratio of
output torque $T_{2;n}$

to input torque $T_{1;n}$

minus efficiency losses

[184] utput torque $T_{2;n}$

[185] to input torque $T_{1;n}$

[186] us efficiency losses

[187] therefore corresponds (apart from the efficiency losses) to the reciprocal of the shaft speeds too
$\mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}$

whereby $\eta _{n;\eta _{0}}$ may vary from gear to gear according to the formulas listed in this table and $0\leq \eta _{n;\eta _{0}}\leq 1$

[188] $\mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}$

[189] whereby $\eta _{n;\eta _{0}}$ may vary from gear to gear according to the formulas listed in this table and $0\leq \eta _{n;\eta _{0}}\leq 1$

[Efficiency-55] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Efficiency
The efficiency $\eta _{n}$ is calculated
from the torque ratio

in relation to the gear ratio (transmission ratio)

$\eta _{n}={\frac {\mu _{n}}{i_{n}}}$

Power loss for single meshing gears
is in the range of 1 % to 1.5 %

helical gear pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range

spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range
Corridor for torque ratio and efficiency
in planetary gearsets, the stationary gear ratio $i_{0}$ is formed via the planetary gears and thus by two meshes

for reasons of simplification, the efficiency for both meshes together is commonly specified there

the efficiencies $\eta _{0}$ specified here are based on assumed efficiencies for the stationary ratio $i_{0}$
of $\eta _{0}=0.9800$ (upper value)

and $\eta _{0}=0.9700$ (lower value)

for both interventions together

The corresponding efficiency
for single-meshing gear pairs is ${\eta _{0}}^{\tfrac {1}{2}}$

at $0.9800^{\tfrac {1}{2}}=0.98995$ (upper value)

and $0.9700^{\tfrac {1}{2}}=0.98489$ (lower value)

[191] The efficiency $\eta _{n}$ is calculated
from the torque ratio

in relation to the gear ratio (transmission ratio)

$\eta _{n}={\frac {\mu _{n}}{i_{n}}}$

[192] rom the torque ratio

[193] relation to the gear ratio (transmission ratio)

[194] $\eta _{n}={\frac {\mu _{n}}{i_{n}}}$

[195] Power loss for single meshing gears
is in the range of 1 % to 1.5 %

helical gear pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range

spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range

[196] s in the range of 1 % to 1.5 %

[197] r pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range

[198] spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range

[199] tary gearsets, the stationary gear ratio $i_{0}$ is formed via the planetary gears and thus by two meshes

[200] r reasons of simplification, the efficiency for both meshes together is commonly specified there

[201] the efficiencies $\eta _{0}$ specified here are based on assumed efficiencies for the stationary ratio $i_{0}$
of $\eta _{0}=0.9800$ (upper value)

and $\eta _{0}=0.9700$ (lower value)

[202] $\eta _{0}=0.9800$ (upper value)

[203] $\eta _{0}=0.9700$ (lower value)

[204] r both interventions together

[205] The corresponding efficiency
for single-meshing gear pairs is ${\eta _{0}}^{\tfrac {1}{2}}$

at $0.9800^{\tfrac {1}{2}}=0.98995$ (upper value)

and $0.9700^{\tfrac {1}{2}}=0.98489$ (lower value)

[206] r single-meshing gear pairs is ${\eta _{0}}^{\tfrac {1}{2}}$

[207] t $0.9800^{\tfrac {1}{2}}=0.98995$ (upper value)

[208] $0.9700^{\tfrac {1}{2}}=0.98489$ (lower value)

[56] Layout
Input and output are on opposite sides

Planetary gearset 1 is on the input (turbine) side

Input (turbine) shaft is S₁

Output shaft is C₃

[210] Input and output are on opposite sides

[211] Planetary gearset 1 is on the input (turbine) side

[212] Input (turbine) shaft is S₁

[213] Output shaft is C₃

[57] Total Ratio Span (Total Gear/Transmission Ratio) Nominal
${\frac {\omega _{2;n}}{\omega _{2;1}}}={\frac {\frac {\omega _{2;n}}{\omega _{2;1}\omega _{2;n}}}{\frac {\omega _{2;1}}{\omega _{2;1}\omega _{2;n}}}}={\frac {\frac {1}{\omega _{2;1}}}{\frac {1}{\omega _{2;n}}}}={\frac {\frac {\omega _{t}}{\omega _{2;1}}}{\frac {\omega _{t}}{\omega _{2;n}}}}={\frac {i_{1}}{i_{n}}}$

A wider span enables the
downspeeding when driving outside the city limits

increase the climbing ability
when driving over mountain passes or off-road

or when towing a trailer

[215] ${\frac {\omega _{2;n}}{\omega _{2;1}}}={\frac {\frac {\omega _{2;n}}{\omega _{2;1}\omega _{2;n}}}{\frac {\omega _{2;1}}{\omega _{2;1}\omega _{2;n}}}}={\frac {\frac {1}{\omega _{2;1}}}{\frac {1}{\omega _{2;n}}}}={\frac {\frac {\omega _{t}}{\omega _{2;1}}}{\frac {\omega _{t}}{\omega _{2;n}}}}={\frac {i_{1}}{i_{n}}}$

[216] A wider span enables the
downspeeding when driving outside the city limits

increase the climbing ability
when driving over mountain passes or off-road

or when towing a trailer

[217] wnspeeding when driving outside the city limits

[218] rease the climbing ability
when driving over mountain passes or off-road

or when towing a trailer

[219] when driving over mountain passes or off-road

[220] r when towing a trailer

[effective-58] Total Ratio Span (Total Gear Ratio/Total Transmission Ratio) Effective
${\frac {\omega _{2;n}}{max(\omega _{2;1};|\omega _{2;R}|)}}={\frac {min(i_{1};|i_{R}|)}{i_{n}}}$

The span is only effective to the extent that
the reverse gear ratio

matches that of 1st gear

see also Standard R:1
Digression
Reverse gear
is usually longer than 1st gear

the effective span is therefore of central importance for describing the suitability of a transmission

because in these cases, the nominal spread conveys a misleading picture

which is only unproblematic for vehicles with high specific power
Market participants
Manufacturers naturally have no interest in specifying the effective span

Users have not yet formulated the practical benefits that the effective span has for them

The effective span has not yet played a role in research and teaching
Contrary to its significance
the effective span has therefore not yet been able to establish itself
either in theory

or in practice.
End of digression

[222] ${\frac {\omega _{2;n}}{max(\omega _{2;1};|\omega _{2;R}|)}}={\frac {min(i_{1};|i_{R}|)}{i_{n}}}$

[223] The span is only effective to the extent that
the reverse gear ratio

matches that of 1st gear

[224] the reverse gear ratio

[225] tches that of 1st gear

[226] see also Standard R:1

[227] s usually longer than 1st gear

[228] the effective span is therefore of central importance for describing the suitability of a transmission

[229] use in these cases, the nominal spread conveys a misleading picture

[230] which is only unproblematic for vehicles with high specific power

[231] Manufacturers naturally have no interest in specifying the effective span

[232] Users have not yet formulated the practical benefits that the effective span has for them

[233] The effective span has not yet played a role in research and teaching

[234] the effective span has therefore not yet been able to establish itself
either in theory

or in practice.

[235] ther in theory

[236] r in practice.

[59] Ratio Span's Center
$(i_{1}i_{n})^{\frac {1}{2}}$

The center indicates the speed level of the transmission

Together with the final drive ratio

it gives the shaft speed level of the vehicle

[238] $(i_{1}i_{n})^{\frac {1}{2}}$

[239] The center indicates the speed level of the transmission

[240] Together with the final drive ratio

[241] t gives the shaft speed level of the vehicle

[60] Average Gear Step
$\left({\frac {\omega _{2;n}}{\omega _{2;1}}}\right)^{\frac {1}{n-1}}=\left({\frac {i_{1}}{i_{n}}}\right)^{\frac {1}{n-1}}$

There are $n-1$ gear steps between $n$ gears

with decreasing step width
the gears connect better to each other

shifting comfort increases

[243] $\left({\frac {\omega _{2;n}}{\omega _{2;1}}}\right)^{\frac {1}{n-1}}=\left({\frac {i_{1}}{i_{n}}}\right)^{\frac {1}{n-1}}$

[244] There are $n-1$ gear steps between $n$ gears

[245] with decreasing step width
the gears connect better to each other

shifting comfort increases

[246] the gears connect better to each other

[247] shifting comfort increases

[61] Sun 1: sun gear of gearset 1

[62] Ring 1: ring gear of gearset 1

[63] Sun 2: sun gear of gearset 2

[64] Ring 2: ring gear of gearset 2

[65] Sun 3: sun gear of gearset 3

[66] Ring 3: ring gear of gearset 3

[50:50-67] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p Standard 50:50
— 50 % Is Above And 50 % Is Below The Average Gear Step —
With steadily decreasing gear steps (yellow highlighted line Step)

and a particularly large step from 1st to 2nd gear
the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger

and the upper half of the gear steps (between the large gears; rounded up, here the last 2) is always smaller

than the average gear step (cell highlighted yellow two rows above on the far right)

lower half: smaller gear steps are a waste of possible ratios (red bold)

upper half: larger gear steps are unsatisfactory (red bold)

[255] With steadily decreasing gear steps (yellow highlighted line Step)

[256] rticularly large step from 1st to 2nd gear
the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger

and the upper half of the gear steps (between the large gears; rounded up, here the last 2) is always smaller

[257] the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger

[258] the upper half of the gear steps (between the large gears; rounded up, here the last 2) is always smaller

[259] than the average gear step (cell highlighted yellow two rows above on the far right)

[260] wer half: smaller gear steps are a waste of possible ratios (red bold)

[261] upper half: larger gear steps are unsatisfactory (red bold)

[R:1-68] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Standard R:1
— Reverse And 1st Gear Have The Same Ratio —
The ideal reverse gear has the same transmission ratio as 1st gear
no impairment when maneuvering

especially when towing a trailer

a torque converter can only partially compensate for this deficiency

Plus 11.11 % minus 10 % compared to 1st gear is good

Plus 25 % minus 20 % is acceptable (red)

Above this is unsatisfactory (bold)

[263] The ideal reverse gear has the same transmission ratio as 1st gear
no impairment when maneuvering

especially when towing a trailer

a torque converter can only partially compensate for this deficiency

[264] rment when maneuvering

[265] specially when towing a trailer

[266] torque converter can only partially compensate for this deficiency

[267] Plus 11.11 % minus 10 % compared to 1st gear is good

[268] Plus 25 % minus 20 % is acceptable (red)

[269] Above this is unsatisfactory (bold)

[1:2-69] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Standard 1:2
— Gear Step 1st To 2nd Gear As Small As Possible —
With continuously decreasing gear steps (yellow marked line Step)

the largest gear step is the one from 1st to 2nd gear, which
for a good speed connection and

a smooth gear shift

must be as small as possible
A gear ratio of up to 1.6667:1 (5:3) is good

Up to 1.7500:1 (7:4) is acceptable (red)

Above is unsatisfactory (bold)

[271] With continuously decreasing gear steps (yellow marked line Step)

[272] the largest gear step is the one from 1st to 2nd gear, which
for a good speed connection and

a smooth gear shift

[273] r a good speed connection and

[274] smooth gear shift

[275] ust be as small as possible
A gear ratio of up to 1.6667:1 (5:3) is good

Up to 1.7500:1 (7:4) is acceptable (red)

Above is unsatisfactory (bold)

[276] A gear ratio of up to 1.6667:1 (5:3) is good

[277] Up to 1.7500:1 (7:4) is acceptable (red)

[278] Above is unsatisfactory (bold)

[LS-70] From large to small gears (from right to left)

[step-71] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Standard STEP
— From Large To Small Gears: Steady And Progressive Increase In Gear Steps —
Gear steps should
increase: Δ Step (first green highlighted line Δ Step) is always greater than 1

As progressive as possible: Δ Step is always greater than the previous step

Not progressively increasing is acceptable (red)

Not increasing is unsatisfactory (bold)

[281] Gear steps should
increase: Δ Step (first green highlighted line Δ Step) is always greater than 1

As progressive as possible: Δ Step is always greater than the previous step

[282] increase: Δ Step (first green highlighted line Δ Step) is always greater than 1

[283] As progressive as possible: Δ Step is always greater than the previous step

[284] Not progressively increasing is acceptable (red)

[285] Not increasing is unsatisfactory (bold)

[speed-72] Standard SPEED
— From Small To Large Gears: Steady Increase In Shaft Speed Difference —
Shaft speed differences should
increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one

1 difference smaller than the previous one is acceptable (red)

2 consecutive ones are a waste of possible ratios (bold)

[287] Shaft speed differences should
increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one

[288] increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one

[289] 1 difference smaller than the previous one is acceptable (red)

[290] 2 consecutive ones are a waste of possible ratios (bold)

[73] K4B 050: for the 6.3 L engine M 100 of the 600 and 300 SEL 6.3

[74] W4A 018: for light-duty trucks and vans up to 5,600 kg (12,350 lb) and off-road vehicles^[B]^[C]

[75] W4B 035: for medium-duty trucks up to 13,000 kg (28,660 lb)^[D]^[E]

[76] Blocks S₂

[77] Blocks S₃

[78] Also BR (brake for reverse gear · German: Bremse für Rückwärtsgang) · Blocks C₁

[79] Couples S₂ with C₂

[80] Couples R₁ with S₃

[ordinary-81] Ordinary Noted
For direct determination of the gear ratio

[300] For direct determination of the gear ratio

[elementary-82] Elementary Noted
Alternative representation for determining the transmission ratio

Contains only operands
With simple fractions of both central gears of a planetary gearset

Or with the value 1

As a basis
For reliable

And traceable

Determination of the torque conversion ratio and efficiency

[302] Alternative representation for determining the transmission ratio

[303] Contains only operands
With simple fractions of both central gears of a planetary gearset

Or with the value 1

[304] With simple fractions of both central gears of a planetary gearset

[305] Or with the value 1

[306] As a basis
For reliable

And traceable

[307] For reliable

[308] And traceable

[309] Determination of the torque conversion ratio and efficiency

[84] us 1 reverse gear

[85] 2 simple planetary gearsets,^[4] 3 brakes, 2 clutches

[86] Revised 14 January 2026
Nomenclature
$S_{n}=$ sun gear: number of teeth

$R_{n}=$ ring gear: number of teeth

$\color {gray}{C_{n}=}$ carrier or planetary gear carrier (not needed)

$s_{n}=$ sun gear: shaft speed

$r_{n}=$ ring gear: shaft speed

$c_{n}=$ carrier or planetary gear carrier: shaft speed
With $n=$ gear is
$i_{n}=$ gear ratio or transmission ratio

$\omega _{1;n}=\omega _{t}=$ shaft speed shaft 1: input (turbine) shaft

$\omega _{2;n}=$ shaft speed shaft 2: output shaft

$T_{1;n}=T_{t}=$ torque shaft 1: input (turbine) shaft

$T_{2;n}=$ torque shaft 2: output shaft

$\mu _{n}=$ torque ratio or torque conversion ratio

$\eta _{n}=$ efficiency

$i_{0}=$ stationary gear ratio

$\eta _{0}=$ (assumed) stationary gear efficiency

[313] $S_{n}=$ sun gear: number of teeth

[314] $R_{n}=$ ring gear: number of teeth

[315] $\color {gray}{C_{n}=}$ carrier or planetary gear carrier (not needed)

[316] $s_{n}=$ sun gear: shaft speed

[317] $r_{n}=$ ring gear: shaft speed

[318] $c_{n}=$ carrier or planetary gear carrier: shaft speed

[319] $i_{n}=$ gear ratio or transmission ratio

[320] $\omega _{1;n}=\omega _{t}=$ shaft speed shaft 1: input (turbine) shaft

[321] $\omega _{2;n}=$ shaft speed shaft 2: output shaft

[322] $T_{1;n}=T_{t}=$ torque shaft 1: input (turbine) shaft

[323] $T_{2;n}=$ torque shaft 2: output shaft

[324] $\mu _{n}=$ torque ratio or torque conversion ratio

[325] $\eta _{n}=$ efficiency

[326] $i_{0}=$ stationary gear ratio

[327] $\eta _{0}=$ (assumed) stationary gear efficiency

[Gear_Ratio-87] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Gear Ratio (Transmission Ratio) $i_{n}$
— Speed Conversion —
The gear ratio $i_{n}$ is the ratio of
input shaft speed $\omega _{1;n}$

to output shaft speed $\omega _{2;n}$

and therefore corresponds to the reciprocal of the shaft speeds
$i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}$

[329] The gear ratio $i_{n}$ is the ratio of
input shaft speed $\omega _{1;n}$

to output shaft speed $\omega _{2;n}$

[330] ut shaft speed $\omega _{1;n}$

[331] to output shaft speed $\omega _{2;n}$

[332] therefore corresponds to the reciprocal of the shaft speeds
$i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}$

[333] $i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}$

[Torque_Ratio-88] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Torque Ratio (Torque Conversion Ratio) $\mu _{n}$
— Torque Conversion —
The torque ratio $\mu _{n}$ is the ratio of
output torque $T_{2;n}$

to input torque $T_{1;n}$

minus efficiency losses

and therefore corresponds (apart from the efficiency losses) to the reciprocal of the shaft speeds too
$\mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}$

whereby $\eta _{n;\eta _{0}}$ may vary from gear to gear according to the formulas listed in this table and $0\leq \eta _{n;\eta _{0}}\leq 1$

[335] The torque ratio $\mu _{n}$ is the ratio of
output torque $T_{2;n}$

to input torque $T_{1;n}$

minus efficiency losses

[336] utput torque $T_{2;n}$

[337] to input torque $T_{1;n}$

[338] us efficiency losses

[339] therefore corresponds (apart from the efficiency losses) to the reciprocal of the shaft speeds too
$\mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}$

whereby $\eta _{n;\eta _{0}}$ may vary from gear to gear according to the formulas listed in this table and $0\leq \eta _{n;\eta _{0}}\leq 1$

[340] $\mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}$

[341] whereby $\eta _{n;\eta _{0}}$ may vary from gear to gear according to the formulas listed in this table and $0\leq \eta _{n;\eta _{0}}\leq 1$

[Efficiency-89] ^ ^a ^b ^c ^d ^e ^f ^g Efficiency
The efficiency $\eta _{n}$ is calculated
from the torque ratio

in relation to the gear ratio (transmission ratio)

$\eta _{n}={\frac {\mu _{n}}{i_{n}}}$

Power loss for single meshing gears
is in the range of 1 % to 1.5 %

helical gear pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range

spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range
Corridor for torque ratio and efficiency
in planetary gearsets, the stationary gear ratio $i_{0}$ is formed via the planetary gears and thus by two meshes

for reasons of simplification, the efficiency for both meshes together is commonly specified there

the efficiencies $\eta _{0}$ specified here are based on assumed efficiencies for the stationary ratio $i_{0}$
of $\eta _{0}=0.9800$ (upper value)

and $\eta _{0}=0.9700$ (lower value)

for both interventions together

The corresponding efficiency
for single-meshing gear pairs is ${\eta _{0}}^{\tfrac {1}{2}}$

at $0.9800^{\tfrac {1}{2}}=0.98995$ (upper value)

and $0.9700^{\tfrac {1}{2}}=0.98489$ (lower value)

[343] The efficiency $\eta _{n}$ is calculated
from the torque ratio

in relation to the gear ratio (transmission ratio)

$\eta _{n}={\frac {\mu _{n}}{i_{n}}}$

[344] rom the torque ratio

[345] relation to the gear ratio (transmission ratio)

[346] $\eta _{n}={\frac {\mu _{n}}{i_{n}}}$

[347] Power loss for single meshing gears
is in the range of 1 % to 1.5 %

helical gear pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range

spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range

[348] s in the range of 1 % to 1.5 %

[349] r pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range

[350] spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range

[351] tary gearsets, the stationary gear ratio $i_{0}$ is formed via the planetary gears and thus by two meshes

[352] r reasons of simplification, the efficiency for both meshes together is commonly specified there

[353] the efficiencies $\eta _{0}$ specified here are based on assumed efficiencies for the stationary ratio $i_{0}$
of $\eta _{0}=0.9800$ (upper value)

and $\eta _{0}=0.9700$ (lower value)

[354] $\eta _{0}=0.9800$ (upper value)

[355] $\eta _{0}=0.9700$ (lower value)

[356] r both interventions together

[357] The corresponding efficiency
for single-meshing gear pairs is ${\eta _{0}}^{\tfrac {1}{2}}$

at $0.9800^{\tfrac {1}{2}}=0.98995$ (upper value)

and $0.9700^{\tfrac {1}{2}}=0.98489$ (lower value)

[358] r single-meshing gear pairs is ${\eta _{0}}^{\tfrac {1}{2}}$

[359] t $0.9800^{\tfrac {1}{2}}=0.98995$ (upper value)

[360] $0.9700^{\tfrac {1}{2}}=0.98489$ (lower value)

[90] Layout
Input and output are on opposite sides

Planetary gearset 1 is on the input (turbine) side

Input (turbine) shaft is R₁

Output shaft is C₂

[362] Input and output are on opposite sides

[363] Planetary gearset 1 is on the input (turbine) side

[364] Input (turbine) shaft is R₁

[365] Output shaft is C₂

[91] Total Ratio Span (Total Gear/Transmission Ratio) Nominal
${\frac {\omega _{2;n}}{\omega _{2;1}}}={\frac {\frac {\omega _{2;n}}{\omega _{2;1}\omega _{2;n}}}{\frac {\omega _{2;1}}{\omega _{2;1}\omega _{2;n}}}}={\frac {\frac {1}{\omega _{2;1}}}{\frac {1}{\omega _{2;n}}}}={\frac {\frac {\omega _{t}}{\omega _{2;1}}}{\frac {\omega _{t}}{\omega _{2;n}}}}={\frac {i_{1}}{i_{n}}}$

A wider span enables the
downspeeding when driving outside the city limits

increase the climbing ability
when driving over mountain passes or off-road

or when towing a trailer

[367] ${\frac {\omega _{2;n}}{\omega _{2;1}}}={\frac {\frac {\omega _{2;n}}{\omega _{2;1}\omega _{2;n}}}{\frac {\omega _{2;1}}{\omega _{2;1}\omega _{2;n}}}}={\frac {\frac {1}{\omega _{2;1}}}{\frac {1}{\omega _{2;n}}}}={\frac {\frac {\omega _{t}}{\omega _{2;1}}}{\frac {\omega _{t}}{\omega _{2;n}}}}={\frac {i_{1}}{i_{n}}}$

[368] A wider span enables the
downspeeding when driving outside the city limits

increase the climbing ability
when driving over mountain passes or off-road

or when towing a trailer

[369] wnspeeding when driving outside the city limits

[370] rease the climbing ability
when driving over mountain passes or off-road

or when towing a trailer

[371] when driving over mountain passes or off-road

[372] r when towing a trailer

[effective-92] ^ ^a ^b ^c ^d ^e ^f ^g Total Ratio Span (Total Gear Ratio/Total Transmission Ratio) Effective
${\frac {\omega _{2;n}}{max(\omega _{2;1};|\omega _{2;R}|)}}={\frac {min(i_{1};|i_{R}|)}{i_{n}}}$

The span is only effective to the extent that
the reverse gear ratio

matches that of 1st gear

see also Standard R:1
Digression
Reverse gear
is usually longer than 1st gear

the effective span is therefore of central importance for describing the suitability of a transmission

because in these cases, the nominal spread conveys a misleading picture

which is only unproblematic for vehicles with high specific power
Market participants
Manufacturers naturally have no interest in specifying the effective span

Users have not yet formulated the practical benefits that the effective span has for them

The effective span has not yet played a role in research and teaching
Contrary to its significance
the effective span has therefore not yet been able to establish itself
either in theory

or in practice.
End of digression

[374] ${\frac {\omega _{2;n}}{max(\omega _{2;1};|\omega _{2;R}|)}}={\frac {min(i_{1};|i_{R}|)}{i_{n}}}$

[375] The span is only effective to the extent that
the reverse gear ratio

matches that of 1st gear

[376] the reverse gear ratio

[377] tches that of 1st gear

[378] see also Standard R:1

[379] s usually longer than 1st gear

[380] the effective span is therefore of central importance for describing the suitability of a transmission

[381] use in these cases, the nominal spread conveys a misleading picture

[382] which is only unproblematic for vehicles with high specific power

[383] Manufacturers naturally have no interest in specifying the effective span

[384] Users have not yet formulated the practical benefits that the effective span has for them

[385] The effective span has not yet played a role in research and teaching

[386] the effective span has therefore not yet been able to establish itself
either in theory

or in practice.

[387] ther in theory

[388] r in practice.

[93] Ratio Span's Center
$(i_{1}i_{n})^{\frac {1}{2}}$

The center indicates the speed level of the transmission

Together with the final drive ratio

it gives the shaft speed level of the vehicle

[390] $(i_{1}i_{n})^{\frac {1}{2}}$

[391] The center indicates the speed level of the transmission

[392] Together with the final drive ratio

[393] t gives the shaft speed level of the vehicle

[94] Average Gear Step
$\left({\frac {\omega _{2;n}}{\omega _{2;1}}}\right)^{\frac {1}{n-1}}=\left({\frac {i_{1}}{i_{n}}}\right)^{\frac {1}{n-1}}$

There are $n-1$ gear steps between $n$ gears

with decreasing step width
the gears connect better to each other

shifting comfort increases

[395] $\left({\frac {\omega _{2;n}}{\omega _{2;1}}}\right)^{\frac {1}{n-1}}=\left({\frac {i_{1}}{i_{n}}}\right)^{\frac {1}{n-1}}$

[396] There are $n-1$ gear steps between $n$ gears

[397] with decreasing step width
the gears connect better to each other

shifting comfort increases

[398] the gears connect better to each other

[399] shifting comfort increases

[95] Sun 1: sun gear of gearset 1

[96] Ring 1: ring gear of gearset 1

[97] Sun 2: sun gear of gearset 2

[98] Ring 2: ring gear of gearset 2

[50:50-99] Standard 50:50
— 50 % Is Above And 50 % Is Below The Average Gear Step —
With steadily decreasing gear steps (yellow highlighted line Step)

and a particularly large step from 1st to 2nd gear
the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger

and the upper half of the gear steps (between the large gears; rounded up, here the last 1) is always smaller

than the average gear step (cell highlighted yellow two rows above on the far right)

lower half: smaller gear steps are a waste of possible ratios (red bold)

upper half: larger gear steps are unsatisfactory (red bold)

[405] With steadily decreasing gear steps (yellow highlighted line Step)

[406] rticularly large step from 1st to 2nd gear
the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger

and the upper half of the gear steps (between the large gears; rounded up, here the last 1) is always smaller

[407] the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger

[408] the upper half of the gear steps (between the large gears; rounded up, here the last 1) is always smaller

[409] than the average gear step (cell highlighted yellow two rows above on the far right)

[410] wer half: smaller gear steps are a waste of possible ratios (red bold)

[411] upper half: larger gear steps are unsatisfactory (red bold)

[R:1-100] ^ ^a ^b ^c ^d ^e ^f ^g ^h Standard R:1
— Reverse And 1st Gear Have The Same Ratio —
The ideal reverse gear has the same transmission ratio as 1st gear
no impairment when maneuvering

especially when towing a trailer

a torque converter can only partially compensate for this deficiency

Plus 11.11 % minus 10 % compared to 1st gear is good

Plus 25 % minus 20 % is acceptable (red)

Above this is unsatisfactory (bold)

[413] The ideal reverse gear has the same transmission ratio as 1st gear
no impairment when maneuvering

especially when towing a trailer

a torque converter can only partially compensate for this deficiency

[414] rment when maneuvering

[415] specially when towing a trailer

[416] torque converter can only partially compensate for this deficiency

[417] Plus 11.11 % minus 10 % compared to 1st gear is good

[418] Plus 25 % minus 20 % is acceptable (red)

[419] Above this is unsatisfactory (bold)

[1:2-101] Standard 1:2
— Gear Step 1st To 2nd Gear As Small As Possible —
With continuously decreasing gear steps (yellow marked line Step)

the largest gear step is the one from 1st to 2nd gear, which
for a good speed connection and

a smooth gear shift

must be as small as possible
A gear ratio of up to 1.6667 : 1 (5 : 3) is good

Up to 1.7500 : 1 (7 : 4) is acceptable (red)

Above is unsatisfactory (bold)

[421] With continuously decreasing gear steps (yellow marked line Step)

[422] the largest gear step is the one from 1st to 2nd gear, which
for a good speed connection and

a smooth gear shift

[423] r a good speed connection and

[424] smooth gear shift

[425] ust be as small as possible
A gear ratio of up to 1.6667 : 1 (5 : 3) is good

Up to 1.7500 : 1 (7 : 4) is acceptable (red)

Above is unsatisfactory (bold)

[426] A gear ratio of up to 1.6667 : 1 (5 : 3) is good

[427] Up to 1.7500 : 1 (7 : 4) is acceptable (red)

[428] Above is unsatisfactory (bold)

[LS-102] From large to small gears (from right to left)

[step-103] Standard STEP
— From Large To Small Gears: Steady And Progressive Increase In Gear Steps —
Gear steps should
increase: Δ Step (first green highlighted line Δ Step) is always greater than 1

As progressive as possible: Δ Step is always greater than the previous step

Not progressively increasing is acceptable (red)

Not increasing is unsatisfactory (bold)

[431] Gear steps should
increase: Δ Step (first green highlighted line Δ Step) is always greater than 1

As progressive as possible: Δ Step is always greater than the previous step

[432] increase: Δ Step (first green highlighted line Δ Step) is always greater than 1

[433] As progressive as possible: Δ Step is always greater than the previous step

[434] Not progressively increasing is acceptable (red)

[435] Not increasing is unsatisfactory (bold)

[speed-104] Standard SPEED
— From Small To Large Gears: Steady Increase In Shaft Speed Difference —
Shaft speed differences should
increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one

1 difference smaller than the previous one is acceptable (red)

2 consecutive ones are a waste of possible ratios (bold)

[437] Shaft speed differences should
increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one

[438] increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one

[439] 1 difference smaller than the previous one is acceptable (red)

[440] 2 consecutive ones are a waste of possible ratios (bold)

[106] W3A 050 reinforced: for the 6.8 L engine M 100 of the 450 SEL 6.9

[107] Blocks S₁

[108] Blocks S₂

[109] Blocks C₁

[110] Couples S₁ with C₁

[111] Couples S₁ with S₂

[ordinary-112] Ordinary Noted
For direct determination of the gear ratio

[448] For direct determination of the gear ratio

[elementary-113] Elementary Noted
Alternative representation for determining the transmission ratio

Contains only operands
With simple fractions of both central gears of a planetary gearset

Or with the value 1

As a basis
For reliable

And traceable

Determination of the torque conversoin ratio and efficiency

[450] Alternative representation for determining the transmission ratio

[451] Contains only operands
With simple fractions of both central gears of a planetary gearset

Or with the value 1

[452] With simple fractions of both central gears of a planetary gearset

[453] Or with the value 1

[454] As a basis
For reliable

And traceable

[455] For reliable

[456] And traceable

[457] Determination of the torque conversoin ratio and efficiency

[Förster_1982_6+20-6] . 6 & 20^[3]

[Förster_1982_7+20-10] ^ ^a ^b ^c ^d ^e ^f ^g pp. 7 & 20^[3]

[light-duty-14] . 487^[5]

[Förster_1982_9+22-16] . 9 & 22^[3]

[medium-duty-17] . 489^[5]

[3-speed-105] . 452^[5]

[50_Yrs-1] "50 years of automatic transmissions from Mercedes-Benz".

[Looman_1970-4] Johannes Looman · Gear Transmissions · pp. 133 ff · German: Johannes Looman · Zahnradgetriebe · Berlin und Heidelberg 1970 · Print ISBN 978-3-540-04894-7 · S. 133 ff

[Förster_1982-5] Result And Outlook · commemorative publication for Prof. Dr. Hans-Joachim Foerster on the occasion of leaving as director from active duty at Daimler-Benz AG · November 1982 · German: Ergebnis und Ausblick · Festschrift für Herrn Prof. Dr. Hans-Joachim Förster zum Ausscheiden als Direktor aus dem aktiven Dienst der Daimler-Benz AG · November 1982

[W_116-12] "MB Passenger Car Series 116" (PDF). · p. 10

[Förster_1991-13] Hans-Joachim Foerster · Automatic Vehicle Transmissions · German: Hans-Joachim Förster · Automatische Fahrzeuggetriebe · Berlin und Heidelberg 1991 · Print ISBN 978-3-642-84119-4 · eBook ISBN 978-3-642-84118-7

[49] "MB Passenger Car Series 116" (PDF). p. 11

[83] Only surpassed by the Mercedes-Benz 770, built from 1930 to 1943

[114] "MB AUS 1979" (PDF). · p. 57

[1]

[a]

[b]

[2]

[A]

[c]

[d]

[e]

[B]

[f]

[4]

[g]

[h]

[i]

[C]

[D]

[E]

[a]

[b]

[c]

[d]

[e]

[f]

[g]

[h]

[i]

[j]

[k]

[l]

[m]

[n]

[o]

[p]

[q]

[r]

[s]

[t]

[u]

[v]

[w]

[x]

[y]

[z]

[aa]

[ab]

[ac]

[6]

[a]

[b]

[c]

[d]

[e]

[f]

[g]

[h]

[i]

[j]

[k]

[l]

[m]

[n]

[o]

[p]

[q]

[r]

[s]

[t]

[u]

[v]

[w]

[x]

[y]

[z]

[aa]

[ab]

[ac]

[ad]

[ae]

[af]

[ag]

[7]

[a]

[b]

[c]

[d]

[e]

[f]

[g]

[h]

[i]

[j]

[k]

[l]

[m]

[n]

[o]

[p]

[q]

[r]

[s]

Key Data

1961: K4A 025— 4-Speed Transmission With 2 Planetary Gearsets —

Layout

Specifications

1964: K4B 050 And Follow-Up Products— 4-Speed Transmissions With 3 Planetary Gearsets —

Layout

Models

1964: K4B 050

1967: K4C 025

1969: K4A 040

1972: W4B 025

Variants For Commercial Cars

Specifications

1971: W3A 040 And Follow-Up Products— 3-Speed Transmissions With 2 Planetary Gearsets —

Layout

Specifications

Applications

K4A 025

K4B 050

K4C 025

K4A 040

W3A 040

W3B 050

W4B 025

See also

Notes

References

1961: K4A 025
— 4-Speed Transmission With 2 Planetary Gearsets —

1964: K4B 050 And Follow-Up Products
— 4-Speed Transmissions With 3 Planetary Gearsets —

1971: W3A 040 And Follow-Up Products
— 3-Speed Transmissions With 2 Planetary Gearsets —