Mercedes-Benz first series automatic transmission

Mercedes-Benz 722.0, 722.1 and 722.2 transmission
Overview
Manufacturer Daimler AG
Production 1961–1983
Body and chassis
Class 4-speed longitudinal automatic transmission
Chronology
Successor 722.3 and 722.4 4G-Tronic

The Mercedes-Benz first series of automatic transmission, designated with series model numbers 722.0, 722.1 and 722.2, is a family of three and four-speed automatic transmission for engines with longitudinal layout for rear wheel drive passenger cars.

This transmission was the first Mercedes-Benz true automatic transmission in house developing.[1] Before this, the company used semi automatics systems like a vacuum-power shifting for overdrive or the "Hydrak" hydraulic automatic clutch system. Alternatively, they bought true automatics transmissions of other vendors, such BorgWarner.

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. Three-speed units use two planetary gear sets and 4-speed units use three planetary gear sets.[2]

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

Units models

722.2 (K4C025 and K4A040)

The 722.2 is the first of the series, launched in April 1961 for the W111 220SEB, later replaced with the 722.0 and 722.1. It is a 4-speed unit and uses fluid coupling (also referred in some manuals as hydraulic/automatic clutch).

722.0 (W3A040 and W3B050)

The 722.0 is the strongest of the series, starting with the W3A040, W3B050 and a reinforced W3B050 (722.003) exclusively used in the W116 450 SEL 6.9. The second in the series, it was released initially for the W116 450SE and SEL in August 1972, and it uses torque converter instead of fluid coupling.[1][2] The transmission is used in V8 engines as a 3-speed unit.

722.1 (W4B025)

The 722.1 is a 4-speed unit, the last released in the series, that also uses torque converter.[2] Used in l4, l5 and l6 engines, it was not used in V8 models because it wasn't designed for handle that amount of torque, instead the 722.0 was used in those engines.

In normal situations, it starts in 2nd gear, but it will use 1st gear if kickdown is actuated (full throttle)[3] or if L position is selected in gear selector.

Applications

722.2

K4C025

K4A040

722.0

W3A040

W3B050

722.1

W4B025

See also

References

  1. 1 2 "50 years of automatic transmissions from Mercedes-Benz".
  2. 1 2 3 "MB Passenger Car Series 116, PDF p. 10" (PDF).
  3. ↑ "MB Passenger Car Series 116, PDF p. 11" (PDF).
  4. ↑ "MB AUS 1979, PDF p. 57" (PDF).


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