Mercedes-Benz first series automatic transmission

Mercedes-Benz K4A 025
K4B 050 · K4C 025 · K4A 040 W3A 040 · W3B 050 · W4B 025
W4A
Contents
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 2
Specifications 2
1971: W3A 040 And Follow-Up Products— 3-Speed Transmissions With 2 Planetary Gearsets —
Layout 3
Specifications 3
Applications
K4C 025
K4A 040
W3A 040
W3B 050
W4B 025
See also
References
018 · W4B 035
Mercedes-Benz K4A 025 K4B 050 · K4C 025 · K4A 040 W3A 040 · W3B 050 · W4B 025 W4AContents 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 2 ; Specifications 2 ; 1971: W3A 040 And Follow-Up Products— 3-Speed Transmissions With 2 Planetary Gearsets — ; Layout 3 ; Specifications 3 ; Applications ; K4C 025 ; K4A 040 ; W3A 040 ; W3B 050 ; W4B 025 ; See also ; References ; 018 · W4B 035
Overview
Manufacturer	Daimler AG
Production	1961–1983
Body and chassis
Class	3 and 4-speed longitudinal automatic transmission
Chronology
Successor	4G-Tronic

Last updated October 28, 2024

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.

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 BorgWarner.

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.

Gear Ratios^{[lower-alpha 1]}
Gear Model	R	1	2	3	4	Total Span	Span Center	Avg. Step	Compo- nents

K4A 025 · 1961	−4.145	3.979	2.520	1.579	1.000	3.979	1.995	1.585	2 Gearsets 3 Brakes 3 Clutches

K4B 050 · 1964	−4.145	3.979	2.459	1.579	1.000	3.979	1.995	1.585	3 Gearsets 3 Brakes 2 Clutches
K4C 025 · 1967 K4A 040 · 1969 W4B 025 · 1972	−5.478	3.983	2.386	1.461	1.000	3.983	1.996	1.585
W4A 018 · 1975	−5.499	4.006	2.391	1.463	1.000	4.006	2.001	1.588
W4B 035 · 1975	−5.881	4.176	2.412	1.462	1.000	4.176	2.043	1.610

W3A 040 · 1971 W3A 050 · 1973 W3A 050 reinf. · 1975	−1.836	2.306	1.461	1.000		2.306	1.519	1.519	2 Gearsets 3 Brakes 2 Clutches

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

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

Layout

The K4A 025^{[lower-alpha 1]} (without type designation) is the first of the series, launched in April 1961 for the W111 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^{[lower-alpha 2]} 8 main components^{[lower-alpha 3]} are used. It is the only exemption which uses only 2 planetary gearsets for 4 speeds.

↑ Kupplungs-4-Gang-Automatik bis 25 kpm Eingangsdrehmoment
(clutch-4-gear-automatic with 25 kp⋅m (181 lb⋅ft) maximum input torque
↑ plus 1 reverse gear
↑ 2 simple planetary gearsets, 3 brakes, 3 clutches

Gear Ratios
With Assessment		Planetary Gearset: Teeth Simple ^{[lower-alpha 1]}		Count	Total^{[lower-alpha 2]} Center^{[lower-alpha 3]}	Avg.^{[lower-alpha 4]}

Model Type	Version First Delivery	S₁^{[lower-alpha 5]} R₁^{[lower-alpha 6]}	S₂^{[lower-alpha 7]} R₂^{[lower-alpha 8]}	Brakes Clutches	Ratio Span	Gear Step^{[lower-alpha 9]}
Gear Ratio		R ${i_{R}}$	1 ${i_{1}}$	2 ${i_{2}}$	3 ${i_{3}}$	4 ${i_{4}}$
Step^{[lower-alpha 9]}		$-{\tfrac {i_{R}}{i_{1}}}$ ^{[lower-alpha 10]}	${\tfrac {i_{1}}{i_{1}}}$	${\tfrac {i_{1}}{i_{2}}}$ ^{[lower-alpha 11]}	${\tfrac {i_{2}}{i_{3}}}$	${\tfrac {i_{3}}{i_{4}}}$
Δ Step^{[lower-alpha 12]}^{[lower-alpha 13]}				${\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}$	${\tfrac {i_{2}}{i_{3}}}:{\tfrac {i_{3}}{i_{4}}}$
Shaft Speed		${\tfrac {i_{1}}{i_{R}}}$	${\tfrac {i_{1}}{i_{1}}}$	${\tfrac {i_{1}}{i_{2}}}$	${\tfrac {i_{1}}{i_{3}}}$	${\tfrac {i_{1}}{i_{4}}}$
Δ Shaft Speed^{[lower-alpha 14]}		$0-{\tfrac {i_{1}}{i_{R}}}$	${\tfrac {i_{1}}{i_{1}}}-0$	${\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}$	${\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}$	${\tfrac {i_{1}}{i_{4}}}-{\tfrac {i_{1}}{i_{3}}}$

K4A 025 N/A	25 kp⋅m (181 lb⋅ft ) 1961^[2]^[3]	50 76	44 76	3 3	3.9789 1.9947	1.5846^{[lower-alpha 9]}
Gear Ratio		−4.1455 $-{\tfrac {228}{55}}$	3.9789 ${\tfrac {378}{95}}$	2.5200^{[lower-alpha 9]}^{[lower-alpha 13]} ${\tfrac {63}{25}}$	1.5789^{[lower-alpha 9]} ${\tfrac {30}{19}}$	1.0000 ${\tfrac {1}{1}}$
Step		1.0418	1.0000	1.5789^{[lower-alpha 9]}	1.5960^{[lower-alpha 9]}	1.5789
Δ Step^{[lower-alpha 12]}				0.9893^{[lower-alpha 13]}	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

Ratio R & Even		$-{\tfrac {R_{1}(S_{2}+R_{2})}{S_{1}S_{2}}}$	${\tfrac {S_{1}+R_{1}}{S_{1}}}$		${\tfrac {1}{1}}$
Ratio Odd			${\tfrac {(S_{1}+R_{1})(S_{2}+R_{2})}{S_{1}R_{2}}}$		${\tfrac {S_{2}+R_{2}}{R_{2}}}$
Algebra And Actuated Shift Elements
Brake A^{[lower-alpha 15]}			❶	❶
Brake B^{[lower-alpha 16]}			❶		❶
Brake R^{[lower-alpha 17]}		❶
Clutch D^{[lower-alpha 18]}					❶	❶
Clutch E^{[lower-alpha 19]}		❶
Clutch F^{[lower-alpha 20]}				❶		❶

↑ 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 (the carrier of gearset 1) Output shaft is C₂ (the carrier of gearset 2) ↑ Total Ratio Span (Total Ratio Spread · Total Gear Ratio) ${\tfrac {i_{n}}{i_{1}}}$ 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 ↑ Ratio Span's Center $(i_{n}i_{1})^{\tfrac {1}{2}}$ 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 $({\tfrac {i_{n}}{i_{1}}})^{\tfrac {1}{n-1}}$ 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 1 2 3 4 5 6 7 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) 1 2 From large to small gears (from right to left) 1 2 3 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 ↑ Blocks C₁(the carrier of gearset 1) ↑ Couples C₁ (the carrier of gearset 2) with the turbine ↑ Couples R₁ with S₂ ↑ Couples S₂ with R₂

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

Layout

The Mercedes-Benz 600 from April 1964, the first post-war "Grand Mercedes", is 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.

The first model with this new layout was the K4B 050 (without type designation). 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.

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 more powerful version of the same design.

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^[5] or if L position is selected in gear selector.

The W4A 018 (type 720.1) was derived from the W4B 025 (type 722.1) for vans up to 5,600 kg (12,350 lb )^[6] and off road vehicles, the W4B 035 from the W4B 025 (type 722.1) and K4A 040 (type 722.2) for light trucks up to 13,000 kg (28,660 lb ).^[7] The main difference is the use of straight toothed planetary gearsets instead of skew toothed ones for better fuel efficiency at the price of lower noise comfort.

Specifications

For this second 4-speed models^{[lower-alpha 1]} 8 main components^{[lower-alpha 2]} are used.^[4]

↑ plus 1 reverse gear
↑ 3 simple planetary gearsets, 3 brakes, 2 clutches

Gear Ratios
With Assessment		Planetary Gearset: Teeth^{[lower-alpha 1]}			Count	Total^{[lower-alpha 2]} Center^{[lower-alpha 3]}	Avg.^{[lower-alpha 4]}
With Assessment		Simpson		Simple	Count	Total^{[lower-alpha 2]} Center^{[lower-alpha 3]}	Avg.^{[lower-alpha 4]}

Model Type	Version First Delivery	S₁^{[lower-alpha 5]} R₁^{[lower-alpha 6]}	S₂^{[lower-alpha 7]} R₂^{[lower-alpha 8]}	S₃^{[lower-alpha 9]} R₃^{[lower-alpha 10]}	Brakes Clutches	Ratio Span	Gear Step^{[lower-alpha 11]}
Gear Ratio		R ${i_{R}}$		1 ${i_{1}}$	2 ${i_{2}}$	3 ${i_{3}}$	4 ${i_{4}}$
Step^{[lower-alpha 11]}		$-{\tfrac {i_{R}}{i_{1}}}$ ^{[lower-alpha 12]}		${\tfrac {i_{1}}{i_{1}}}$	${\tfrac {i_{1}}{i_{2}}}$ ^{[lower-alpha 13]}	${\tfrac {i_{2}}{i_{3}}}$	${\tfrac {i_{3}}{i_{4}}}$
Δ Step^{[lower-alpha 14]}^{[lower-alpha 15]}					${\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}$	${\tfrac {i_{2}}{i_{3}}}:{\tfrac {i_{3}}{i_{4}}}$
Shaft Speed		${\tfrac {i_{1}}{i_{R}}}$		${\tfrac {i_{1}}{i_{1}}}$	${\tfrac {i_{1}}{i_{2}}}$	${\tfrac {i_{1}}{i_{3}}}$	${\tfrac {i_{1}}{i_{4}}}$
Δ Shaft Speed^{[lower-alpha 16]}		$0-{\tfrac {i_{1}}{i_{R}}}$		${\tfrac {i_{1}}{i_{1}}}-0$	${\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}$	${\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}$	${\tfrac {i_{1}}{i_{4}}}-{\tfrac {i_{1}}{i_{3}}}$

K4B 050 N/A	51 kp⋅m (369 lb⋅ft ) 1964	50 76	44 76	44 76	3 2	3.9789 1.9947	1.5846^{[lower-alpha 11]}
Gear Ratio		−4.1455 $-{\tfrac {228}{55}}$		3.9789 ${\tfrac {378}{95}}$	2.4589 ${\tfrac {1,168}{475}}$	1.5789^{[lower-alpha 15]}	1.0000 ${\tfrac {1}{1}}$
Step		1.0418		1.0000	1.6182	1.5573	1.5789
Δ Step^{[lower-alpha 14]}					1.0391	0.9863^{[lower-alpha 15]}
Speed		-0.9598		1.0000	1.6182	2.5200	3.9789
Δ Speed		0.9598		1.0000	0.6182	0.9018	1.4589

K4C 025 722.2	25 kp⋅m (181 lb⋅ft ) 1967^[6]	44 76	44 76	35 76	3 2	3.9833 1.9958	1.5852^{[lower-alpha 11]}
Gear Ratio		−5.4779^{[lower-alpha 12]} $-{\tfrac {2,109}{385}}$		3.9833 ${\tfrac {1,665}{418}}$	2.3855^{[lower-alpha 13]}^{[lower-alpha 15]} ${\tfrac {5,439}{2,280}}$	1.4605^{[lower-alpha 11]} ${\tfrac {111}{76}}$	1.0000 ${\tfrac {1}{1}}$
Step		1.3752^{[lower-alpha 12]}		1.0000	1.6698^{[lower-alpha 13]}	1.6333^{[lower-alpha 11]}	1.4605
Δ Step^{[lower-alpha 14]}					1.0223^{[lower-alpha 15]}	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

K4A 040 722.2	40 kp⋅m (289 lb⋅ft ) 1969	44 76	44 76	35 76	3 2	3.9833 1.9958	1.5852^{[lower-alpha 11]}
Ratio		−5.4779^{[lower-alpha 12]}		3.9833	2.3855^{[lower-alpha 13]}^{[lower-alpha 15]}	1.4605^{[lower-alpha 11]}	1.0000

W4B 025 722.1	25 kp⋅m (181 lb⋅ft ) 1972^[6]	44 76	44 76	35 76	3 2	3.9833 1.9958	1.5852^{[lower-alpha 11]}
Ratio		−5.4779^{[lower-alpha 12]}		3.9833	2.3855^{[lower-alpha 13]}^{[lower-alpha 15]}	1.4605^{[lower-alpha 11]}	1.0000

W4A 018^{[lower-alpha 17]} 720.1	18 kp⋅m (130 lb⋅ft ) 1975	46 80	46 80	37 80	3 2	4.0060 2.0015	1.5882^{[lower-alpha 11]}
Gear Ratio		−5.4994^{[lower-alpha 12]} $-{\tfrac {4,680}{851}}$		4.0060 ${\tfrac {7,371}{1840}}$	2.3911^{[lower-alpha 13]}^{[lower-alpha 15]} ${\tfrac {1,339}{560}}$	1.4625^{[lower-alpha 11]} ${\tfrac {117}{80}}$	1.0000 ${\tfrac {1}{1}}$
Step		1.3728^{[lower-alpha 12]}		1.0000	1.6754^{[lower-alpha 13]}	1.6349^{[lower-alpha 11]}	1.4625
Δ Step^{[lower-alpha 14]}					1.0248^{[lower-alpha 15]}	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

W4B 035^{[lower-alpha 18]} N/A	35 kp⋅m (253 lb⋅ft ) 1975	42 78	42 78	36 78	3 2	4.1758 2.0435	1.6103^{[lower-alpha 11]}
Gear Ratio		−5.8810^{[lower-alpha 12]} $-{\tfrac {2,223}{378}}$		4.1758 ${\tfrac {3,420}{819}}$	2.4115^{[lower-alpha 13]}^{[lower-alpha 15]} ${\tfrac {627}{260}}$	1.4615^{[lower-alpha 11]} ${\tfrac {57}{39}}$	1.0000 ${\tfrac {1}{1}}$
Step		1.4083^{[lower-alpha 12]}		1.0000	1.7360^{[lower-alpha 13]}	1.6500^{[lower-alpha 11]}	1.4615
Δ Step^{[lower-alpha 14]}					1.0495^{[lower-alpha 15]}	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

Ratio R & Even		$-{\tfrac {R_{1}(S_{3}+R_{3})}{S_{1}S_{3}}}$		${\tfrac {(S_{1}(S_{2}+R_{2})+R_{1}S_{2})(S_{3}+R_{3})}{S_{1}(S_{2}+R_{2})R_{3}}}$			${\tfrac {1}{1}}$
Ratio Odd			$i_{1}={\tfrac {(S_{1}+R_{1})(S_{3}+R_{3})}{S_{1}R_{3}}}$			$i_{3}={\tfrac {S_{3}+R_{3}}{R_{3}}}$
Algebra And Actuated Shift Elements
Brake A^{[lower-alpha 19]}					❶
Brake B^{[lower-alpha 20]}				❶	❶	❶
Brake R^{[lower-alpha 21]}		❶
Clutch D^{[lower-alpha 22]}						❶	❶
Clutch E^{[lower-alpha 23]}		❶		❶			❶

↑ Layout Input and output are on opposite sides Planetary gearset 1 is on the input (turbine) side Input shafts is S₁ Output shaft is C₃ (the carrier of gearset 3) ↑ Total Ratio Span (Total Ratio Spread · Total Gear Ratio) ${\tfrac {i_{n}}{i_{1}}}$ 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 ↑ Ratio Span's Center $(i_{n}i_{1})^{\tfrac {1}{2}}$ 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 $({\tfrac {i_{n}}{i_{1}}})^{\tfrac {1}{n-1}}$ 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 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 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) 1 2 3 4 5 6 7 8 9 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) 1 2 3 4 5 6 7 8 9 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) 1 2 3 4 5 From large to small gears (from right to left) 1 2 3 4 5 6 7 8 9 10 11 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) ↑ for light duty trucks up to 5,600 kg (12,350 lb)^[6]^[8] ↑ for medium duty trucks up to 13,000 kg (28,660 lb)^[7]^[9] ↑ Blocks S₂ ↑ Blocks S₃ ↑ Blocks C₁(the carrier of gearset 1) ↑ Couples S₂ with C₂ (the carrier of gearset 2) ↑ Couples R₁ with S₃

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 Mercedes-Benz W108 and W109 in 1971. The second in the series is the W3B 050, which was released initially for the W116 450 SE and SEL in 1973. At that time the 4-speed transmission for the 350 SE and 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 Mercedes-Benz M100 engine, the biggest Mercedes-Benz engine in post-war history,^[10] exclusively used in the W116 450 SEL 6.9.

Specifications

For the 3-speed models^{[lower-alpha 1]} 7 main components^{[lower-alpha 2]} are used, which shows economic equivalence with the direct competitor.

↑ plus 1 reverse gear
↑ 2 simple planetary gearsets,^[4] 3 brakes, 2 clutches

Gear Ratios
With Assessment		Simple Planetary Gearset: Teeth^{[lower-alpha 1]}		Count	Total^{[lower-alpha 2]} Center^{[lower-alpha 3]}	Avg.^{[lower-alpha 4]}

Model Type	Version First Delivery	S₁^{[lower-alpha 5]} R₁^{[lower-alpha 6]}	S₂^{[lower-alpha 7]} R₂^{[lower-alpha 8]}	Brakes Clutches	Ratio Span	Gear Step^{[lower-alpha 9]}
Gear Ratio		R ${i_{R}}$		1 ${i_{1}}$	2 ${i_{2}}$	3 ${i_{3}}$
Step^{[lower-alpha 9]}		$-{\tfrac {i_{R}}{i_{1}}}$ ^{[lower-alpha 10]}		${\tfrac {i_{1}}{i_{1}}}$	${\tfrac {i_{1}}{i_{2}}}$ ^{[lower-alpha 11]}	${\tfrac {i_{2}}{i_{3}}}$
Δ Step^{[lower-alpha 12]}^{[lower-alpha 13]}					${\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}$
Shaft Speed		${\tfrac {i_{1}}{i_{R}}}$		${\tfrac {i_{1}}{i_{1}}}$	${\tfrac {i_{1}}{i_{2}}}$	${\tfrac {i_{1}}{i_{3}}}$
Δ Shaft Speed^{[lower-alpha 14]}		$0-{\tfrac {i_{1}}{i_{R}}}$		${\tfrac {i_{1}}{i_{1}}}-0$	${\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}$	${\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}$

W4A 040 722.0	40 kp⋅m (289 lb⋅ft ) 1971^[11]	44 76	35 76	3 2	2.3061 1.5186	1.5186^{[lower-alpha 9]}
Gear Ratio		−1.8361^{[lower-alpha 10]} $-{\tfrac {1,221}{665}}$		2.3061 ${\tfrac {1,665}{722}}$	1.4605 ${\tfrac {63}{25}}$	1.0000 ${\tfrac {1}{1}}$
Step		0.7962^{[lower-alpha 10]}		1.0000	1.5789	1.4605
Δ Step^{[lower-alpha 12]}					1.0811
Speed		-1.2560		1.0000	1.5789	2.3061
Δ Speed		1.2560		1.0000	0.5789	0.9411

W4A 050 722.0	50 kp⋅m (362 lb⋅ft ) 1973^[11]	44 76	35 76	3 2	2.3061 1.5186	1.5186^{[lower-alpha 9]}
Ratio		−1.8361^{[lower-alpha 10]}		2.3061	1.4605	1.0000

W4A 050 reinf. 722.0	56 kp⋅m (405 lb⋅ft ) 1975^[11]	44 76	35 76	3 2	2.3061 1.5186	1.5186^{[lower-alpha 9]}
Ratio		−1.8361^{[lower-alpha 10]}		2.3061	1.4605	1.0000

Ratio	$-{\tfrac {S_{1}(S_{2}+R_{2})}{R_{1}S_{2}}}$		${\tfrac {(S_{1}+R_{1})(S_{2}+R_{2})}{R_{1}R_{2}}}$		${\tfrac {S_{2}+R_{2}}{R_{2}}}$	${\tfrac {1}{1}}$
Algebra And Actuated Shift Elements
Brake A^{[lower-alpha 15]}				❶
Brake B^{[lower-alpha 16]}				❶	❶
Brake R^{[lower-alpha 17]}		❶
Clutch D^{[lower-alpha 18]}					❶	❶
Clutch E^{[lower-alpha 19]}		❶				❶

↑ Layout Input and output are on opposite sides Planetary gearset 1 is on the input (turbine) side Input shafts is R₁ Output shaft is C₂ (the carrier of gearset 2) ↑ Total Ratio Span (Total Ratio Spread · Total Gear Ratio) ${\tfrac {i_{n}}{i_{1}}}$ 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 ↑ Ratio Span's Center $(i_{n}i_{1})^{\tfrac {1}{2}}$ 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 $({\tfrac {i_{n}}{i_{1}}})^{\tfrac {1}{n-1}}$ 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 1 2 3 4 5 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) 1 2 3 4 5 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) 1 2 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) ↑ Blocks S₁ ↑ Blocks S₂ ↑ Blocks C₁(the carrier of gearset 1) ↑ Couples S₁ with C₁ (the carrier of gearset 2) ↑ Couples S₁ with S₂

Applications

K4C 025

W114 and W115
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

W109 and W108
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

R107 and C107
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

W109 and W108
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

R107 and C107
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

W116
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

R107 and C107
Chassis code	Car model	Engine code	Transmission code	Notes
107.044	450 SL	117.982 (D-Jet) 117.985 (K-Jet)	722.004	worldwide except USA and Japan
107.024	450 SLC	117.982 (D-Jet) 117.985 (K-Jet)	722.004	worldwide except USA and Japan

W116
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^[12]

W4B 025

R107 and C107
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

W114 and W115
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

W116
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

W123
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

References

1 2 "50 years of automatic transmissions from Mercedes-Benz".
↑ Johannes Looman · Zahnradgetriebe · pp. 133 ff · Berlin and Heidelberg 1970 · Print ISBN 978-3-540-04894-7
↑ 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 (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) · pp. 6 · 20
1 2 3 4 "MB Passenger Car Series 116, PDF p. 10" (PDF).
↑ "MB Passenger Car Series 116, PDF p. 11" (PDF).
1 2 3 4 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 (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) · pp. 7 · 20
1 2 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 (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) · pp. 9 · 22
↑ Hans Joachim Foerster · Automatische Fahrzeuggetriebe · p. 487 · Berlin and Heidelberg 1991 · Print ISBN 978-3-642-84119-4 · Online ISBN 978-3-642-84118-7
↑ Hans Joachim Foerster · Automatische Fahrzeuggetriebe · p. 489 · Berlin and Heidelberg 1991 · Print ISBN 978-3-642-84119-4 · Online ISBN 978-3-642-84118-7
↑ Only surpassed by the Mercedes-Benz 770, built from 1930 to 1943
1 2 3 Hans Joachim Foerster · Automatische Fahrzeuggetriebe · p. 452 · Berlin and Heidelberg 1991 · Print ISBN 978-3-642-84119-4 · Online ISBN 978-3-642-84118-7
↑ "MB AUS 1979, PDF p. 57" (PDF).

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

[3] Kupplungs-4-Gang-Automatik bis 25 kpm Eingangsdrehmoment
(clutch-4-gear-automatic with 25 kp⋅m (181 lb⋅ft) maximum input torque

[4] us 1 reverse gear

[5] 2 simple planetary gearsets, 3 brakes, 3 clutches

[6] 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 (the carrier of gearset 1)
Output shaft is C₂ (the carrier of gearset 2)

[mwAlA] Input and output are on opposite sides

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

[mwAlI] Input shafts is S₁ and, if actuated, C₁ (the carrier of gearset 1)

[mwAlc] Output shaft is C₂ (the carrier of gearset 2)

[7] Total Ratio Span (Total Ratio Spread · Total Gear Ratio)
${\tfrac {i_{n}}{i_{1}}}$
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

[mwAl8] ${\tfrac {i_{n}}{i_{1}}}$

[mwAnM] 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

[mwAnU] wnspeeding when driving outside the city limits

[mwAnY] rease the climbing ability
when driving over mountain passes or off-road
or when towing a trailer

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

[mwAnk] r when towing a trailer

[8] Ratio Span's Center
$(i_{n}i_{1})^{\tfrac {1}{2}}$
The center indicates the speed level of the transmission
Together with the final drive ratio
it gives the shaft speed level of the vehicle

[mwAn8] $(i_{n}i_{1})^{\tfrac {1}{2}}$

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

[mwApk] Together with the final drive ratio

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

[9] Average Gear Step
$({\tfrac {i_{n}}{i_{1}}})^{\tfrac {1}{n-1}}$
With decreasing step width
the gears connect better to each other
shifting comfort increases

[mwAqA] $({\tfrac {i_{n}}{i_{1}}})^{\tfrac {1}{n-1}}$

[mwAr8] With decreasing step width
the gears connect better to each other
shifting comfort increases

[mwAsE] the gears connect better to each other

[mwAsI] shifting comfort increases

[10] Sun 1: sun gear of gearset 1

[11] Ring 1: ring gear of gearset 1

[12] Sun 2: sun gear of gearset 2

[13] Ring 2: ring gear of gearset 2

[50:50-14] 1 2 3 4 5 6 7 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)

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

[mwAuo] 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

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

[mwAu8] the upper half of the gear steps (between the large gears; rounded up, here the last 2) is always smaller

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

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

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

[R:1-15] 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)

[mwAwc] 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

[mwAwk] rment when maneuvering

[mwAwo] specially when towing a trailer

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

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

[mwAw8] Plus 25 % minus 20 % is acceptable (red)

[mwAxM] Above this is unsatisfactory (bold)

[1:2-16] 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)

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

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

[mwAyY] r a good speed connection and

[mwAyc] smooth gear shift

[mwAyg] 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)

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

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

[mwAy0] Above is unsatisfactory (bold)

[LS-17] 1 2 From large to small gears (from right to left)

[step-18] 1 2 3 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)

[mwA0Q] 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

[mwA0Y] increase: Δ Step (first green highlighted line Δ Step) is always greater than 1

[mwA0s] As progressive as possible: Δ Step is always greater than the previous step

[mwA04] Not progressively increasing is acceptable (red)

[mwA1A] Not increasing is unsatisfactory (bold)

[speed-19] 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)

[mwA14] Shaft speed differences should
increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one

[mwA2A] increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one

[mwA2U] 1 difference smaller than the previous one is acceptable (red)

[mwA2c] 2 consecutive ones are a waste of possible ratios (bold)

[22] Blocks R₁

[23] Blocks S₂

[24] Blocks C₁(the carrier of gearset 1)

[25] Couples C₁ (the carrier of gearset 2) with the turbine

[26] Couples R₁ with S₂

[27] Couples S₂ with R₂

[32] us 1 reverse gear

[33] 3 simple planetary gearsets, 3 brakes, 2 clutches

[34] Layout
Input and output are on opposite sides
Planetary gearset 1 is on the input (turbine) side
Input shafts is S₁
Output shaft is C₃ (the carrier of gearset 3)

[mwBsM] Input and output are on opposite sides

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

[mwBsU] Input shafts is S₁

[mwBsg] Output shaft is C₃ (the carrier of gearset 3)

[35] Total Ratio Span (Total Ratio Spread · Total Gear Ratio)
${\tfrac {i_{n}}{i_{1}}}$
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

[mwBtA] ${\tfrac {i_{n}}{i_{1}}}$

[mwBuQ] 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

[mwBuY] wnspeeding when driving outside the city limits

[mwBuc] rease the climbing ability
when driving over mountain passes or off-road
or when towing a trailer

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

[mwBuo] r when towing a trailer

[36] Ratio Span's Center
$(i_{n}i_{1})^{\tfrac {1}{2}}$
The center indicates the speed level of the transmission
Together with the final drive ratio
it gives the shaft speed level of the vehicle

[mwBvA] $(i_{n}i_{1})^{\tfrac {1}{2}}$

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

[mwBwo] Together with the final drive ratio

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

[37] Average Gear Step
$({\tfrac {i_{n}}{i_{1}}})^{\tfrac {1}{n-1}}$
With decreasing step width
the gears connect better to each other
shifting comfort increases

[mwBxE] $({\tfrac {i_{n}}{i_{1}}})^{\tfrac {1}{n-1}}$

[mwBzA] With decreasing step width
the gears connect better to each other
shifting comfort increases

[mwBzI] the gears connect better to each other

[mwBzM] shifting comfort increases

[38] Sun 1: sun gear of gearset 1

[39] Ring 1: ring gear of gearset 1

[40] Sun 2: sun gear of gearset 2

[41] Ring 2: ring gear of gearset 2

[42] Sun 3: sun gear of gearset 3

[43] Ring 3: ring gear of gearset 3

[50:50-44] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 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)

[mwB3E] With steadily decreasing gear steps (yellow highlighted line Step)

[mwB3M] 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

[mwB3U] the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger

[mwB3g] the upper half of the gear steps (between the large gears; rounded up, here the last 2) is always smaller

[mwB3s] than the average gear step (cell highlighted yellow two rows above on the far right)

[mwB30] wer half: smaller gear steps are a waste of possible ratios (red bold)

[mwB4E] upper half: larger gear steps are unsatisfactory (red bold)

[R:1-45] 1 2 3 4 5 6 7 8 9 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)

[mwB6A] 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

[mwB6I] rment when maneuvering

[mwB6M] specially when towing a trailer

[mwB6Q] torque converter can only partially compensate for this deficiency

[mwB6U] Plus 11.11 % minus 10 % compared to 1st gear is good

[mwB6g] Plus 25 % minus 20 % is acceptable (red)

[mwB6w] Above this is unsatisfactory (bold)

[1:2-46] 1 2 3 4 5 6 7 8 9 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)

[mwB8o] With continuously decreasing gear steps (yellow marked line Step)

[mwB8w] the largest gear step is the one from 1st to 2nd gear, which
for a good speed connection and
a smooth gear shift

[mwB88] r a good speed connection and

[mwB9A] smooth gear shift

[mwB9E] 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)

[mwB9M] A gear ratio of up to 1.6667:1 (5:3) is good

[mwB9Q] Up to 1.7500:1 (7:4) is acceptable (red)

[mwB9Y] Above is unsatisfactory (bold)

[LS-47] 1 2 3 4 5 From large to small gears (from right to left)

[step-48] 1 2 3 4 5 6 7 8 9 10 11 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)

[mwCAM] 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

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

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

[mwCA0] Not progressively increasing is acceptable (red)

[mwCA8] Not increasing is unsatisfactory (bold)

[speed-49] 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)

[mwCB0] Shaft speed differences should
increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one

[mwCB8] increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one

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

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

[51] r light duty trucks up to 5,600 kg (12,350 lb)^[6]^[8]

[53] r medium duty trucks up to 13,000 kg (28,660 lb)^[7]^[9]

[54] Blocks S₂

[55] Blocks S₃

[56] Blocks C₁(the carrier of gearset 1)

[57] Couples S₂ with C₂ (the carrier of gearset 2)

[58] Couples R₁ with S₃

[60] us 1 reverse gear

[61] 2 simple planetary gearsets,^[4] 3 brakes, 2 clutches

[62] Layout
Input and output are on opposite sides
Planetary gearset 1 is on the input (turbine) side
Input shafts is R₁
Output shaft is C₂ (the carrier of gearset 2)

[mwCgk] Input and output are on opposite sides

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

[mwCgs] Input shafts is R₁

[mwCg4] Output shaft is C₂ (the carrier of gearset 2)

[63] Total Ratio Span (Total Ratio Spread · Total Gear Ratio)
${\tfrac {i_{n}}{i_{1}}}$
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

[mwChY] ${\tfrac {i_{n}}{i_{1}}}$

[mwCio] 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

[mwCiw] wnspeeding when driving outside the city limits

[mwCi0] rease the climbing ability
when driving over mountain passes or off-road
or when towing a trailer

[mwCi8] when driving over mountain passes or off-road

[mwCjA] r when towing a trailer

[64] Ratio Span's Center
$(i_{n}i_{1})^{\tfrac {1}{2}}$
The center indicates the speed level of the transmission
Together with the final drive ratio
it gives the shaft speed level of the vehicle

[mwCjY] $(i_{n}i_{1})^{\tfrac {1}{2}}$

[mwCk8] The center indicates the speed level of the transmission

[mwClA] Together with the final drive ratio

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

[65] Average Gear Step
$({\tfrac {i_{n}}{i_{1}}})^{\tfrac {1}{n-1}}$
With decreasing step width
the gears connect better to each other
shifting comfort increases

[mwClc] $({\tfrac {i_{n}}{i_{1}}})^{\tfrac {1}{n-1}}$

[mwCnY] With decreasing step width
the gears connect better to each other
shifting comfort increases

[mwCng] the gears connect better to each other

[mwCnk] shifting comfort increases

[66] Sun 1: sun gear of gearset 1

[67] Ring 1: ring gear of gearset 1

[68] Sun 2: sun gear of gearset 2

[69] Ring 2: ring gear of gearset 2

[50:50-70] 1 2 3 4 5 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)

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

[mwCp0] 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

[mwCp8] the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger

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

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

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

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

[R:1-71] 1 2 3 4 5 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)

[mwCsI] 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

[mwCsQ] rment when maneuvering

[mwCsU] specially when towing a trailer

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

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

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

[mwCs4] Above this is unsatisfactory (bold)

[1:2-72] 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)

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

[mwCt4] the largest gear step is the one from 1st to 2nd gear, which
for a good speed connection and
a smooth gear shift

[mwCuE] r a good speed connection and

[mwCuI] smooth gear shift

[mwCuM] 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)

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

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

[mwCug] Above is unsatisfactory (bold)

[LS-73] 1 2 From large to small gears (from right to left)

[step-74] 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)

[mwCvs] 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

[mwCv0] increase: Δ Step (first green highlighted line Δ Step) is always greater than 1

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

[mwCwU] Not progressively increasing is acceptable (red)

[mwCwc] Not increasing is unsatisfactory (bold)

[speed-75] 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)

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

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

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

[mwCx4] 2 consecutive ones are a waste of possible ratios (bold)

[77] Blocks S₁

[78] Blocks S₂

[79] Blocks C₁(the carrier of gearset 1)

[80] Couples S₁ with C₁ (the carrier of gearset 2)

[81] Couples S₁ with S₂

[ARTREF-1-1] 1 2 "50 years of automatic transmissions from Mercedes-Benz".

[20] Johannes Looman · Zahnradgetriebe · pp. 133 ff · Berlin and Heidelberg 1970 · Print ISBN 978-3-540-04894-7

[21] 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 (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) · pp. 6 · 20

[ARTREF-2-28] 1 2 3 4 "MB Passenger Car Series 116, PDF p. 10" (PDF).

[ARTREF-3-29] "MB Passenger Car Series 116, PDF p. 11" (PDF).

[Festschrift_1-30] 1 2 3 4 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 (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) · pp. 7 · 20

[Festschrift_2-31] 1 2 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 (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) · pp. 9 · 22

[50] Hans Joachim Foerster · Automatische Fahrzeuggetriebe · p. 487 · Berlin and Heidelberg 1991 · Print ISBN 978-3-642-84119-4 · Online ISBN 978-3-642-84118-7

[52] Hans Joachim Foerster · Automatische Fahrzeuggetriebe · p. 489 · Berlin and Heidelberg 1991 · Print ISBN 978-3-642-84119-4 · Online ISBN 978-3-642-84118-7

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

[Förster_W3-76] 1 2 3 Hans Joachim Foerster · Automatische Fahrzeuggetriebe · p. 452 · Berlin and Heidelberg 1991 · Print ISBN 978-3-642-84119-4 · Online ISBN 978-3-642-84118-7

[ARTREF-4-82] "MB AUS 1979, PDF p. 57" (PDF).

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Mercedes-Benz first series automatic transmission

Contents

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

Specifications

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

Layout

Specifications

Applications

K4C 025

K4A 040

W3A 040

W3B 050

W4B 025

See also

Related Research Articles

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 —