Audi 80/Avant (B4)

since 1991-1995 release

Repair and operation of the car

Audi 80/Avant
+ Technical specification
+ Engines
+ System of production of the fulfilled gases
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and airintaking channels
+ System of injection
+ Coupling
- Transmission and transmission
   Removal and installation of the mechanical transmission (T)
   Noise in the transmission
   Automatic Transmission (AT)
   Electronic control of AKP
   Main transfer
   Power shafts
   Check of cuffs of power shafts
   List of malfunctions
+ Suspension bracket and steering
+ Brake system
+ Anti-blocking system of brakes
+ Wheels and tires
+ Body electrical system
+ System of ignition
+ Lighting
+ Signaling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ Body elements
+ Search of malfunctions
+ Specifications

Automatic Transmission (AT)

The automatic Audi 80 transmission is operated electronically/hydraulically. Along with four transfers this transmission is supplied also with two programs of switching. The driver can choose whether he wants to move, saving fuel (the Sport button is not pressed, AKP switches in the economic program an overgear as soon as possible), or he wants as it is possible to use more stoutly engine capacity (the Sport button is pressed, in the separate ranges of change of the transfer relation of AKP switches an overgear only on higher turns).

General principle of action

Kernel of AKP are so-called planetary ranks. They consist of a gear wheel around which three more gear wheels rotate. The ring gear wheel with internal gearing from above is put on all this. Similar knots are in pairs collected in one tooth gearing and form own small two-speed transmission. In similar transmissions the way of their switching is ingenious.

Change of transfer number happens only by retardation or an otpuskaniye of elements of planetary ranks. Thus there is a switching without interruption of effort. Retardation and an otpuskaniye is provided hydraulically with the operated multidisk couplings and multidisk brakes. To receive the multistage transmission, three planetary rows are one by one connected. So there is a four-speed transmission with the reverse gear. Coordination of the tooth gearing is provided by hydraulic control of the transmission.


Hydrotransformer section shows blades of a pump wheel and the directing wheel clearly. The arrow indicates a frictional overlay of coupling for connection of a pump wheel with the engine which – except for service conditions from cold ATF – since higher transfers switches to the rigid through drive for prevention of slipping.

Transfer of draft of the engine on the transmission happens by means of liquid. The engine sets in motion a pump wheel in the torque converter. The liquid of the transformer given to rotation can set in turn now in motion the turbine wheel connected with the transmission by means of the directing wheel located between both wheels.

Between the pump wheel and a turbine wheel rotating with a frequency of rotation of a shaft of the engine on a transmission entrance there is always a difference in speed. At start-off from the place this difference is the greatest, are more and more compared to increase in speed of frequency of rotation of a pump and turbine wheel. But the ordinary automatic transmission all the same has certain "slipping". In our transmission the torque converter in the third and fourth ranges of change of the transfer relation is blocked, i.e. between the engine and AKP there is a rigid connection. Thus fuel is saved.