Mercedes-Benz 4G-Tronic transmission

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Mercedes-Benz 4G-Tronic transmission is the unofficial name given to the transmission by car enthusiasts. It was produced from 1979 to 1996 in W4A 040, W4A 028 (both type 722.3), W4A 020 (type 722.4), and W5A 030 (type 722.5) variants.

The W4A 040 and the W4A 020 were used until mid-1996. The W4A 028 variant was used for off-road applications (RWD and 4X4). The W5A 030 is basically the same transmission with an additional electrically controlled 5th gear overdrive section attached to the main body in a separate housing; it was available as an extra charge option. All 4G-Tronics were succeeded by the more modern and economic 5G-Tronic (Type 722.6) transmission that features an integrated 5th gear overdrive ratio, torque converter lock-up and fully electronic control.

Gear RatiosTemplate:Efn
Template:Diagonal split header	R	1	2	3	4	5	Total Span	Span Center	Avg. Step	Compo- nents

W4A 040 I · 1979	Template:Round	Template:Round	Template:Round	Template:Round	Template:Round		Template:Round	Template:Round	Template:Round	3 Gearsets 3 Brakes 2 Clutches
W4A 020 · 1982	Template:Round	Template:Round	Template:Round	Template:Round	Template:Round		Template:Round	Template:Round	Template:Round
W4A 040 II · 1985	Template:Round	Template:Round	Template:Round	Template:Round	Template:Round		Template:Round	Template:Round	Template:Round
W4A 028 · 1990	Template:Round	Template:Round	Template:Round	Template:Round	Template:Round		Template:Round	Template:Round	Template:Round

W5A 030 · 1990	Template:Round	Template:Round	Template:Round	Template:Round	Template:Round	Template:Round	Template:Round	Template:Round	Template:Round	4 Gearsets 4 Brakes 3 Clutches

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Specifications

Basic concept

The 4G-Tronic transmission is a hydraulically operated 4-speed automatic without lock-up that replaced the similarly designed W3A 040, W3B 050, and W4B 025 family of automatic transmissions with the introduction of the W126 S-Class in 1979. In some models it is calibrated to move off in second gear to reduce "creeping" and provide a smoother ride, selecting 1st only if the selector is in "2" or in case of abrupt acceleration. Other calibrations have the transmission rest in 2nd gear and kick down to 1st as soon as the accelerator is touched but before the throttle is opened. In some V8 installations a small control unit activates the kick down solenoid when the brake pedal is released so that the car moves off in 1st gear. Other attributes of this transmission include a 2-3 shift delay when the engine is cold in order to speed up catalyst warm-up. 4th gear is a 1:1 ratio. Controls are all mechanical and pneumatic, except for the kickdown solenoid and 2-3 upshift delay solenoid on some models.

In some markets a W-S (Winter - Standard / Sport) switch was provided on the shifter. Activating S mode changes a linkage which effectively shortens the throttle pressure bowden cable. This causes later, higher RPM shifts and on some models a move off in 1st gear instead of 2nd. On V8 models a B (Brake) range is available on the shifter. This activates the kickdown solenoid, forcing the transmission to shift down to 1st sooner for increased engine braking. A hydraulically activated piston prevents shifting into Reverse when the car is moving forward.

Models from 1990 and earlier allow for push starting the engine. They are fitted with a secondary fluid pump, driven by the transmission output shaft. When the vehicle is rolling at 20 mph shifting from Neutral to the 2 range will couple power to the engine. The secondary pump and thus the push starting facility was eliminated for the 1991 model year.

It is considered by enthusiasts to be one of the most reliable transmissions ever built by Mercedes-Benz with some examples exceeding 300,000 miles of service.

Layout

For this W4A-models 4 forward gearsTemplate:Efn using 8 main componentsTemplate:Efn^[1]^[2] show economic equivalence with the direct predecessor.Template:Efn 5 forward gearsTemplate:Efn out of 11 main componentsTemplate:Efn^[1]^[2] and the need of 2 housingsTemplate:Efn and 2 different controlsTemplate:Efn turn out the W5A 030 as the least economically designed automatic transmission ever manufactured for passenger cars. Obviously a transition solution: the direct successor, launched in 1996, requires 9 main components,Template:Efn 1 housing and 1 control.Template:Efn

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Gear Ratios
With Assessment		Planetary Gearset: TeethTemplate:Efn				Count	TotalTemplate:Efn CenterTemplate:Efn	Avg.Template:Efn
With Assessment		Ravigneaux		Simple		Count	TotalTemplate:Efn CenterTemplate:Efn	Avg.Template:Efn

Model Type	Version First Delivery	S₁Template:Efn R₁Template:Efn	S₂Template:Efn R₂Template:Efn	S₃Template:Efn R₃Template:Efn	S₄Template:Efn R₄Template:Efn	Brakes Clutches	Ratio Span	Gear StepTemplate:Efn
Gear Ratio		R $i_{R}$		1 $i_{1}$	2 $i_{2}$	3 $i_{3}$	4 $i_{4}$	5 $i_{5}$
StepTemplate:Efn		$- \frac{i_{R}}{i_{1}}$ Template:Efn		$\frac{i_{1}}{i_{1}}$	$\frac{i_{1}}{i_{2}}$ Template:Efn	$\frac{i_{2}}{i_{3}}$	$\frac{i_{3}}{i_{4}}$	$\frac{i_{4}}{i_{5}}$
Δ StepTemplate:Efn Template:Efn					$\frac{i_{1}}{i_{2}} : \frac{i_{2}}{i_{3}}$	$\frac{i_{2}}{i_{3}} : \frac{i_{3}}{i_{4}}$	$\frac{i_{3}}{i_{4}} : \frac{i_{4}}{i_{5}}$
Shaft Speed		$\frac{i_{1}}{i_{R}}$		$\frac{i_{1}}{i_{1}}$	$\frac{i_{1}}{i_{2}}$	$\frac{i_{1}}{i_{3}}$	$\frac{i_{1}}{i_{4}}$	$\frac{i_{1}}{i_{5}}$
Δ Shaft SpeedTemplate:Efn		$0 - \frac{i_{1}}{i_{R}}$		$\frac{i_{1}}{i_{1}} - 0$	$\frac{i_{1}}{i_{2}} - \frac{i_{1}}{i_{1}}$	$\frac{i_{1}}{i_{3}} - \frac{i_{1}}{i_{2}}$	$\frac{i_{1}}{i_{4}} - \frac{i_{1}}{i_{3}}$	$\frac{i_{1}}{i_{5}} - \frac{i_{1}}{i_{4}}$

W4A 040 I 722.3	Template:Convert 1979^[1]^[2]	34 50	50 78	34 78		3 2	Template:Round Template:Round	Template:Font color Template:Efn
Gear Ratio		Template:Font color		Template:Round $\frac{3, 584}{975}$	Template:Font color	Template:Font color	1.0000 $\frac{1}{1}$
Step		Template:Font color Template:Efn		1.0000	Template:Font color Template:Efn	Template:Font color Template:Efn	1.4359
Δ StepTemplate:Efn					Template:Font color Template:Efn	1.1700
Speed		Template:Font color		1.0000	1.5238	2.5600	3.6759
Δ Speed		Template:Font color		1.0000	0.5238	1.0362	1.1159

W4A 020 722.4	Template:Convert 1982^[1]^[2]	26 42	42 78	38 78		3 2	Template:Round Template:Round	Template:Round Template:Efn
Gear Ratio		Template:Font color		Template:Round $\frac{1, 160}{273}$	Template:Font color	Template:Round $\frac{58}{39}$	1.0000 $\frac{1}{1}$
Step		Template:Font color Template:Efn		1.0000	Template:Font color Template:Efn	1.6190	1.4872
Δ StepTemplate:Efn					1.0900	1.0887
Speed		Template:Font color		1.0000	1.76478	2.8571	4.2491
Δ Speed		Template:Font color		1.0000	0.7647	1.0924	1.3919

W4A 040 II 722.3	Template:Convert 1985^[1]	26 46	46 78	34 78		3 2	Template:Round Template:Round	Template:Round Template:Efn
Ratio		Template:Font color		Template:Round	Template:Font color	Template:Round	1.0000

W4A 028 722.3	Template:Convert 1990^[1]	26 46	46 78	34 78		3 2	Template:Round Template:Round	Template:Round Template:Efn
Ratio		Template:Font color		Template:Round	Template:Font color	Template:Round	1.0000

W5A 030 722.5	Template:Convert 1990^[1]	26 46	46 78	34 78	26 78	4 3	Template:Round Template:Round	Template:Round Template:Efn
Gear Ratio		Template:Font color		Template:Round $\frac{3, 472}{897}$	Template:Font color	Template:Round $\frac{56}{39}$	1.0000 $\frac{1}{1}$	Template:Round $\frac{3}{4}$
Step		Template:Font color Template:Efn		1.0000	Template:Font color Template:Efn	1.5652	1.4359	1.3333
Δ StepTemplate:Efn					1.1003	1.0901	1.0769
Speed		Template:Font color		1.0000	1.7222	2.6957	3.8707	5.1609
Δ Speed		Template:Font color		1.0000	0.7222	0.9734	1.1750	1.2902

Ratio R & Even		$- \frac{R_{2} (S_{3} + R_{3})}{S_{2} S_{3}}$		$\frac{(S_{1} + R_{1}) (S_{3} + R_{3})}{R_{1} R_{3}}$			$\frac{1}{1}$
Ratio Odd		$\frac{(S_{2} + R_{2}) (S_{3} + R_{3})}{S_{2} R_{3}}$			$\frac{S_{3} + R_{3}}{R_{3}}$		$\frac{R_{4}}{S_{4} + R_{4}}$
Algebra And Actuated Shift Elements
Brake ATemplate:Efn					❶
Brake BTemplate:Efn				❶	❶	❶
Brake RTemplate:Efn		❶
Brake STemplate:Efn								❶
Clutch ETemplate:Efn						❶	❶	❶
Clutch FTemplate:Efn		❶		❶			❶	❶
Clutch STemplate:Efn		❶		❶	❶	❶	❶

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Applications

The 4G-Tronic has been used in many Mercedes-Benz cars.

W4A 040 I+II (Type 722.3)

1981–1989 R107 and C107
1989–1996 R129

1981–1985 W123
Chassis code	Car model	Engine code	Transmission code	Notes
123.026	250	123.920 123.921	722.308
123.086	250 T
123.028	250 Lang
123.033	280 E	110.984 110.988	722.300 722.309
123.093	280 TE		722.309
123.053	280 CE		722.300 722.309
123.133	300 D Turbo	617.952	722.315 1982–1985	USA only
123.153	300 CD Turbo		722.315 1982–1985	USA only
123.193	300 TD Turbo		722.303 1981–1982 722.315 1982–1985	USA only

1985–1996 W124
1979–1991 W126
1991–1996 W140
1985–1993 W201
1995–1996 W210

W4A 028 (Type 722.3)

1990–1996 G-Class 463

W4A 020 (Type 722.4)

1982–1985 W123
Chassis code	Car model	Engine code	Transmission code	Notes
123.220	200	102.920 102.939	722.406
123.280	200 T	102.920 102.939	722.406
123.223	230 E	102.980	722.401
123.283	230 TE
123.243	230 CE
123.120	200 D	615.940	722.407
123.123	240 D	616.912	722.404
123.183	240 TD
123.125	240 D Lang
123.130	300 D	617.912	722.405
123.190	300 TD
123.132	300 D Lang
123.133	300 D Turbo	617.952	722.416 1985	California only
123.153	300 CD Turbo
123.193	300 TD Turbo

1985–1996 W124
1982–1993 W201
1993–1996 W202
1995–1996 W210

W5A 030 (Type 722.5)

1990–1996 W124
1991–1996 W140
1995–1996 W210
1990–1996 R129

References

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↑ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 ^1.6 Hans Joachim Foerster · Automatische Fahrzeuggetriebe · Page 171 and 192 · Berlin and Heidelberg 1991 · Print Template:ISBN · Online Template:ISBN
↑ ^2.0 ^2.1 ^2.2 ^2.3 Mercedes 722.3 & 722.4 Technical Overview

[Training_1-1] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 ^1.6 Hans Joachim Foerster · Automatische Fahrzeuggetriebe · Page 171 and 192 · Berlin and Heidelberg 1991 · Print Template:ISBN · Online Template:ISBN

[Training_2-2] 2.0 ^2.1 ^2.2 ^2.3 Mercedes 722.3 & 722.4 Technical Overview

[1]

[2]

Mercedes-Benz 4G-Tronic transmission

Contents

Specifications

Basic concept

Layout

Applications

W4A 040 I+II (Type 722.3)

W4A 028 (Type 722.3)

W4A 020 (Type 722.4)

W5A 030 (Type 722.5)

See also

References

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Mercedes-Benz 4G-Tronic transmission

Specifications

Basic concept

Layout

Applications

W4A 040 I+II (Type 722.3)

W4A 028 (Type 722.3)

W4A 020 (Type 722.4)

W5A 030 (Type 722.5)

See also

References

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