# Mercedes-Benz first series automatic transmission

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. 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.
Gear Ratios :
| GearModel | 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 | 3 Gearsets 3 Brakes 2 Clutches |
| W4A 018 · 1975 | −5.499 | 4.006 | 2.391 | 1.463 | 1.000 | 4.006 | 2.001 | 1.588 | 3 Gearsets 3 Brakes 2 Clutches |
| W4B 035 · 1975 | −5.881 | 4.176 | 2.412 | 1.462 | 1.000 | 4.176 | 2.043 | 1.610 | 3 Gearsets 3 Brakes 2 Clutches |
| 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 |

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

The K4A 025 (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 8 main components 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 | With Assessment | Planetary Gearset: Teeth Simple | Planetary Gearset: Teeth Simple | Count | Total Center | Avg. |
| Model Type | Version First Delivery | S$_1$ R$_1$ | S$_2$ R$_2$ | Brakes Clutches | Ratio Span | Gear Step |
| Gear Ratio | | R ${i_{R}}$ | 1 ${i_{1}}$ | 2 ${i_{2}}$ | 3 ${i_{3}}$ | 4 ${i_{4}}$ |
| Step | | $-{\tfrac {i_{R}}{i_{1}}}$ | ${\tfrac {i_{1}}{i_{1}}}$ | ${\tfrac {i_{1}}{i_{2}}}$ | ${\tfrac {i_{2}}{i_{3}}}$ | ${\tfrac {i_{3}}{i_{4}}}$ |
| Δ Step | | | | ${\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}$ | ${\tfrac {i_{2}}{i_{3}}}:{\tfrac {i_{3}}{i_{4}}}$ | |
| 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 | | $0-{\tfrac {i_{1}}{i_{R}}}$ | ${\tfrac {i_{1}}{i_{1}}}-0$ | ${\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}$ | ${\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}$ | ${\tfrac {i_{1}}{i_{4}}}-{\tfrac {i_{1}}{i_{3}}}$ |
| K4A 025 N/A | 25 kp⋅m (181 lb⋅ft) 1961 | 50 76 | 44 76 | 3 3 | 3.9789 1.9947 | 1.5846 |
| Gear Ratio | | −4.1455 $-{\tfrac {228}{55}}$ | 3.9789 ${\tfrac {378}{95}}$ | 2.5200 ${\tfrac {63}{25}}$ | 1.5789 ${\tfrac {30}{19}}$ | 1.0000 ${\tfrac {1}{1}}$ |
| Step | | 1.0418 | 1.0000 | 1.5789 | 1.5960 | 1.5789 |
| Δ Step | | | | 0.9893 | 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 | | $-{\tfrac {R_{1}(S_{2}+R_{2})}{S_{1}S_{2}}}$ | ${\tfrac {S_{1}+R_{1}}{S_{1}}}$ | ${\tfrac {S_{1}+R_{1}}{S_{1}}}$ | ${\tfrac {1}{1}}$ |
| Ratio Odd | | | ${\tfrac {(S_{1}+R_{1})(S_{2}+R_{2})}{S_{1}R_{2}}}$ | ${\tfrac {(S_{1}+R_{1})(S_{2}+R_{2})}{S_{1}R_{2}}}$ | ${\tfrac {S_{2}+R_{2}}{R_{2}}}$ | ${\tfrac {S_{2}+R_{2}}{R_{2}}}$ |
| Algebra And Actuated Shift Elements |||||||
| Brake A | | | ❶ | ❶ | | |
| Brake B | | | ❶ | | ❶ | |
| Brake R | | ❶ | | | | |
| Clutch D | | | | | ❶ | ❶ |
| Clutch E | | ❶ | | | | |
| Clutch F | | | | ❶ | | ❶ |
| ↑ Layout Input and output are on opposite sides Planetary gearset 1 is on the input (turbine) side Input shafts is S$_1$ and, if actuated, C$_1$ (the carrier of gearset 1) Output shaft is C$_2$ (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 R$_1$ ↑ Blocks S$_2$ ↑ Blocks C$_1$(the carrier of gearset 1) ↑ Couples C$_1$ (the carrier of gearset 2) with the turbine ↑ Couples R$_1$ with S$_2$ ↑ Couples S$_2$ with R$_2$ |||||||

## 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). 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 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) 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). 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 8 main components are used.
* ↑ plus 1 reverse gear
* ↑ 3 simple planetary gearsets, 3 brakes, 2 clutches
Gear Ratios :
| With Assessment | With Assessment | Planetary Gearset: Teeth | Planetary Gearset: Teeth | Planetary Gearset: Teeth | Count | Total Center | Avg. |
| With Assessment | With Assessment | Simpson | Simpson | Simple | Count | Total Center | Avg. |
| Model Type | Version First Delivery | S$_1$ R$_1$ | S$_2$ R$_2$ | S$_3$ R$_3$ | Brakes Clutches | Ratio Span | Gear Step |
| Gear Ratio | | R ${i_{R}}$ | | 1 ${i_{1}}$ | 2 ${i_{2}}$ | 3 ${i_{3}}$ | 4 ${i_{4}}$ |
| Step | | $-{\tfrac {i_{R}}{i_{1}}}$ | | ${\tfrac {i_{1}}{i_{1}}}$ | ${\tfrac {i_{1}}{i_{2}}}$ | ${\tfrac {i_{2}}{i_{3}}}$ | ${\tfrac {i_{3}}{i_{4}}}$ |
| Δ Step | | | | | ${\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}$ | ${\tfrac {i_{2}}{i_{3}}}:{\tfrac {i_{3}}{i_{4}}}$ | |
| 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 | | $0-{\tfrac {i_{1}}{i_{R}}}$ | | ${\tfrac {i_{1}}{i_{1}}}-0$ | ${\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}$ | ${\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}$ | ${\tfrac {i_{1}}{i_{4}}}-{\tfrac {i_{1}}{i_{3}}}$ |
| 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 |
| Gear Ratio | | −4.1455 $-{\tfrac {228}{55}}$ | | 3.9789 ${\tfrac {378}{95}}$ | 2.4589 ${\tfrac {1,168}{475}}$ | 1.5789 | 1.0000 ${\tfrac {1}{1}}$ |
| Step | | 1.0418 | | 1.0000 | 1.6182 | 1.5573 | 1.5789 |
| Δ Step | | | | | 1.0391 | 0.9863 | |
| 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 | 44 76 | 44 76 | 35 76 | 3 2 | 3.9833 1.9958 | 1.5852 |
| Gear Ratio | | −5.4779 $-{\tfrac {2,109}{385}}$ | | 3.9833 ${\tfrac {1,665}{418}}$ | 2.3855 ${\tfrac {5,439}{2,280}}$ | 1.4605 ${\tfrac {111}{76}}$ | 1.0000 ${\tfrac {1}{1}}$ |
| Step | | 1.3752 | | 1.0000 | 1.6698 | 1.6333 | 1.4605 |
| Δ Step | | | | | 1.0223 | 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 |
| Ratio | | −5.4779 | | 3.9833 | 2.3855 | 1.4605 | 1.0000 |
| W4B 025 722.1 | 25 kp⋅m (181 lb⋅ft) 1972 | 44 76 | 44 76 | 35 76 | 3 2 | 3.9833 1.9958 | 1.5852 |
| Ratio | | −5.4779 | | 3.9833 | 2.3855 | 1.4605 | 1.0000 |
| W4A 018 720.1 | 18 kp⋅m (130 lb⋅ft) 1975 | 46 80 | 46 80 | 37 80 | 3 2 | 4.0060 2.0015 | 1.5882 |
| Gear Ratio | | −5.4994 $-{\tfrac {4,680}{851}}$ | | 4.0060 ${\tfrac {7,371}{1840}}$ | 2.3911 ${\tfrac {1,339}{560}}$ | 1.4625 ${\tfrac {117}{80}}$ | 1.0000 ${\tfrac {1}{1}}$ |
| Step | | 1.3728 | | 1.0000 | 1.6754 | 1.6349 | 1.4625 |
| Δ Step | | | | | 1.0248 | 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 N/A | 35 kp⋅m (253 lb⋅ft) 1975 | 42 78 | 42 78 | 36 78 | 3 2 | 4.1758 2.0435 | 1.6103 |
| Gear Ratio | | −5.8810 $-{\tfrac {2,223}{378}}$ | | 4.1758 ${\tfrac {3,420}{819}}$ | 2.4115 ${\tfrac {627}{260}}$ | 1.4615 ${\tfrac {57}{39}}$ | 1.0000 ${\tfrac {1}{1}}$ |
| Step | | 1.4083 | | 1.0000 | 1.7360 | 1.6500 | 1.4615 |
| Δ Step | | | | | 1.0495 | 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 | | $-{\tfrac {R_{1}(S_{3}+R_{3})}{S_{1}S_{3}}}$ | $-{\tfrac {R_{1}(S_{3}+R_{3})}{S_{1}S_{3}}}$ | ${\tfrac {(S_{1}(S_{2}+R_{2})+R_{1}S_{2})(S_{3}+R_{3})}{S_{1}(S_{2}+R_{2})R_{3}}}$ | ${\tfrac {(S_{1}(S_{2}+R_{2})+R_{1}S_{2})(S_{3}+R_{3})}{S_{1}(S_{2}+R_{2})R_{3}}}$ | ${\tfrac {(S_{1}(S_{2}+R_{2})+R_{1}S_{2})(S_{3}+R_{3})}{S_{1}(S_{2}+R_{2})R_{3}}}$ | ${\tfrac {1}{1}}$ |
| Ratio Odd | | | $i_{1}={\tfrac {(S_{1}+R_{1})(S_{3}+R_{3})}{S_{1}R_{3}}}$ | $i_{1}={\tfrac {(S_{1}+R_{1})(S_{3}+R_{3})}{S_{1}R_{3}}}$ | $i_{1}={\tfrac {(S_{1}+R_{1})(S_{3}+R_{3})}{S_{1}R_{3}}}$ | $i_{3}={\tfrac {S_{3}+R_{3}}{R_{3}}}$ | $i_{3}={\tfrac {S_{3}+R_{3}}{R_{3}}}$ |
| Algebra And Actuated Shift Elements ||||||||
| Brake A | | | | | ❶ | | |
| Brake B | | | | ❶ | ❶ | ❶ | |
| Brake R | | ❶ | | | | | |
| Clutch D | | | | | | ❶ | ❶ |
| Clutch E | | ❶ | | ❶ | | | ❶ |
| ↑ Layout Input and output are on opposite sides Planetary gearset 1 is on the input (turbine) side Input shafts is S$_1$ Output shaft is C$_3$ (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) ↑ for medium duty trucks up to 13,000 kg (28,660 lb) ↑ Blocks S$_2$ ↑ Blocks S$_3$ ↑ Blocks C$_1$(the carrier of gearset 1) ↑ Couples S$_2$ with C$_2$ (the carrier of gearset 2) ↑ Couples R$_1$ with S$_3$ ||||||||

## 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. 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, exclusively used in the W116 450 SEL 6.9.

### Specifications

For the 3-speed models 7 main components are used, which shows economic equivalence with the direct competitor.
* ↑ plus 1 reverse gear
* ↑ 2 simple planetary gearsets, 3 brakes, 2 clutches
Gear Ratios :
| With Assessment | With Assessment | Simple Planetary Gearset: Teeth | Simple Planetary Gearset: Teeth | Count | Total Center | Avg. |
| Model Type | Version First Delivery | S$_1$ R$_1$ | S$_2$ R$_2$ | Brakes Clutches | Ratio Span | Gear Step |
| Gear Ratio | | R ${i_{R}}$ | | 1 ${i_{1}}$ | 2 ${i_{2}}$ | 3 ${i_{3}}$ |
| Step | | $-{\tfrac {i_{R}}{i_{1}}}$ | | ${\tfrac {i_{1}}{i_{1}}}$ | ${\tfrac {i_{1}}{i_{2}}}$ | ${\tfrac {i_{2}}{i_{3}}}$ |
| Δ Step | | | | | ${\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}$ | |
| 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 | | $0-{\tfrac {i_{1}}{i_{R}}}$ | | ${\tfrac {i_{1}}{i_{1}}}-0$ | ${\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}$ | ${\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}$ |
| W4A 040 722.0 | 40 kp⋅m (289 lb⋅ft) 1971 | 44 76 | 35 76 | 3 2 | 2.3061 1.5186 | 1.5186 |
| Gear Ratio | | −1.8361 $-{\tfrac {1,221}{665}}$ | | 2.3061 ${\tfrac {1,665}{722}}$ | 1.4605 ${\tfrac {63}{25}}$ | 1.0000 ${\tfrac {1}{1}}$ |
| Step | | 0.7962 | | 1.0000 | 1.5789 | 1.4605 |
| Δ Step | | | | | 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 | 44 76 | 35 76 | 3 2 | 2.3061 1.5186 | 1.5186 |
| Ratio | | −1.8361 | | 2.3061 | 1.4605 | 1.0000 |
| W4A 050 reinf. 722.0 | 56 kp⋅m (405 lb⋅ft) 1975 | 44 76 | 35 76 | 3 2 | 2.3061 1.5186 | 1.5186 |
| Ratio | | −1.8361 | | 2.3061 | 1.4605 | 1.0000 |
| Ratio | $-{\tfrac {S_{1}(S_{2}+R_{2})}{R_{1}S_{2}}}$ | $-{\tfrac {S_{1}(S_{2}+R_{2})}{R_{1}S_{2}}}$ | ${\tfrac {(S_{1}+R_{1})(S_{2}+R_{2})}{R_{1}R_{2}}}$ | ${\tfrac {(S_{1}+R_{1})(S_{2}+R_{2})}{R_{1}R_{2}}}$ | ${\tfrac {S_{2}+R_{2}}{R_{2}}}$ | ${\tfrac {1}{1}}$ |
| Algebra And Actuated Shift Elements |||||||
| Brake A | | | | ❶ | | |
| Brake B | | | | ❶ | ❶ | |
| Brake R | | ❶ | | | | |
| Clutch D | | | | | ❶ | ❶ |
| Clutch E | | ❶ | | | | ❶ |
| ↑ Layout Input and output are on opposite sides Planetary gearset 1 is on the input (turbine) side Input shafts is R$_1$ Output shaft is C$_2$ (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 S$_1$ ↑ Blocks S$_2$ ↑ Blocks C$_1$(the carrier of gearset 1) ↑ Couples S$_1$ with C$_1$ (the carrier of gearset 2) ↑ Couples S$_1$ with S$_2$ |||||||

## Applications
### K4A 025

W108 W109 W110 W111 W112 W113

### 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 | 722.206 |
| 115.112 | 220 D Lang | 615.912 | 722.206 |

### 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 | 3.5 L M 116 V8 | 722.201 | worldwide except USA |
| 108.068 | 280 SEL 3.5 | 3.5 L M 116 V8 | 722.201 | worldwide except USA |
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 | 4.5 L M 117 V8 | 722.000 | USA only |
| 108.058 | 280 SEL 4.5 | 4.5 L M 117 V8 | 722.000 | USA only |
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) | 722.001 | worldwide except USA and Japan |
| 107.024 | 450 SLC | 117.982 (D-Jet) 117.985 (K-Jet) | 722.001 | worldwide except USA and Japan |
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 |

### 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 | 722.107 |
| 115.112 | 220 D Lang | 615.912 | 722.107 |
| 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 | 115.954 | 722.119 |
| 123.043 | 230 C | 115.954 | 722.119 |
| 123.223 | 230 E | 102.980 | 722.122 |
| 123.283 | 230 TE | 102.980 | 722.122 |
| 123.243 | 230 CE | 102.980 | 722.122 |
| 123.026 | 250 | 123.920 123.921 | 722.113 |
| 123.086 | 250 T | 123.920 123.921 | 722.113 |
| 123.028 | 250 Lang | 123.920 123.921 | 722.113 |
| 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 | 110.984 110.988 | 722.112 |
| 123.053 | 280 CE | 110.984 110.988 | 722.112 |
| 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 | 616.912 | 722.117 |
| 123.125 | 240 D Lang | 616.912 | 722.117 |
| 123.130 | 300 D | 617.912 | 722.118 |
| 123.190 | 300 TD | 617.912 | 722.118 |
| 123.132 | 300 D Lang | 617.912 | 722.118 |
| 123.150 | 300 CD | 617.912 | 722.118 | USA only |