20.2. General information
On the Mercedes-Benz cars establish 4-or 5-staged automatic transmissions.
The automatic box consists of the hydrotransformer, the epycyclic tooth gearing, and also coupling and brakes with the hydraulic drive.
The torque from the engine to the transmission is transmitted through the hydrotransformer which performs function of liquid coupling and operates as automatic coupling, also provides torque transmission at acceleration.
The epycyclic tooth gearing provides advance on one of four or five transfers or the movement with a backing. Components of the tooth gearing cope brakes and clutch couplings which are put in action hydraulically. The pump located in the transmission provides necessary hydraulic pressure for work of brakes and a clutch coupling.
The control of the transmission is made by the lever of the selector and two switches. Situation D provides the automatic choice of one of four or five transfers. The automatic mechanism of compulsory inclusion of a low gear of KICK DOWN forcibly switches transfer to the lowest if the pedal of an accelerator is pressed against the stop. This mode needs to be used when the maximum acceleration of the car is required. If the lever of the selector is in situation 3, the car will move only on the first three transfers, and in situation 2 - only on the first two transfers etc. Installation of lower transfers is desirable when braking by the engine, at the movement from biases or for prevention of the undesirable choice of the highest transfer on twisting roads.
By means of additional switches it is possible to set two modes of the movement: economic (Е) or standard (S).
Because of complexity of the automatic transmission any repair has to be made at service station.