Mercedes S-Class W-140

1991-1999 of release

Repair and car operation

Mercedes S-Class
+ Mercedes-Benz Cars of a class S (W-140)
+ Operation manual
+ Routine maintenance
+ Engine
+ Systems of cooling, heating
+ Power supply system and release
+ engine Electric equipment
+ gear shifting Box
- Автоматичеcкая transmission
   Search of malfunctions - the general information
   + Automatic transmission 722.5
   + Automatic transmission 722.6
+ Coupling
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment


Автоматичеcкая transmission

General information

Automatic transmission, in the course of a troganiye from a place, carries out function of ordinary coupling, and during movement performs work on gear shifting.

The AT main hubs are: torque converter (hydrotransformer), planetary reducer and hydraulic or electronic control system. Hydrodriving disk brakes and disk coupling are applied to transition to another transfer the relation in a planetary reducer.

Design of typical AT

Design of typical AT

1 — the Tube of filling of transmission by oil
2 — Schild
3 — the 13-contact socket
4 — Transmission
5 — a driveshaft Flange
6 — Blocking of provision of a parking

7 — Draught of the selector
8 — release System
9 — the Arm of system of release
10 — the Crossbeam with a support
11 — the Tyre of connection with weight

Cut of automatic transmission

1 — the Entrance shaft
2 — ECU
3 — the Intermediate shaft
4 — the Blocking gear wheel of a parking
5 — the Target shaft
6 — the Oil pump
7 — Gidrotransformator
8 — a reactor Shaft
9 — the Blocking coupling of the hydrotransformer
В1 — Multidisk brake assembly В1

В2 — Multidisk brake assembly В2
В3 — Multidisk brake assembly В3
F1 — F1 Flywheel
F2 — F2 Flywheel
N — Back planetary assembly
К1 — Multidisk coupling К1
К2 — Multidisk coupling К2
К3 — Multidisk coupling К3
M — the Central planetary assembly
V\Forward planetary assembly

The torque converter on the functions corresponds to hydraulic coupling. Its task includes coupling implementation at a troganiye from a place and gear shifting.

The control system of transmission (known as electronic system of synchronous switching) is the component of the modified control system of the engine established only on model from AT.

Scheme of an arrangement of electronic components of a control system

Location of the AT control unit (N15/3). In an impellent compartment, on the right at a partition

The control system can work in a special safe mode to which passes at detection of any malfunction. Thus operating modes of transmission are limited, and the car can be delivered under the own steam to repair shop. Upon transition of a control system to a safe mode on a control panel the control lamp (address to Head the Operation manual) lights up.

Analyzing information arriving from various sensors (not only the sensors which are directly related to transmission), the control system chooses optimum from the point of view of profitability, smoothness of a course etc. a box operating mode. At the certain provision of a zaslonka of a throttle the control system can block the hydrotransformer in such a manner that the fourth and fifth transfers will join only. It reaches considerable decrease in consumption of fuel.

The unique regular procedure of service of a box is check of level of working liquid (see. Section Check of levels of liquids, control of leakages of Head Routine maintenance). Regularly to change transmission liquid it is not necessary.

Near a radiator of system of cooling the cooler of transmission liquid is established.

The traditional switch of the kickdown mode is not present. Activation of a mode is carried out directly by a control system of transmission after processing of information arriving from the sensor of provision of a butterfly valve.

There are some operating modes of transmission, each of which can be involved after moving of the selector to one of the following provisions: «P», «R», «N», «D», «1», «2», «3», «4» (address to Head the Operation manual).

The engine can be started only if the selector is in the situation "R" or "N". It is made to prevent car movement in start attempt (if the selector is established in one of other provisions). Analyzing information arriving from sensors, the control system resolves or forbids engine start. The locations of various relays are specified in Head Onboard electric equipment).