Fig. 8.81. Passat SYNCRO car transmission: 1–differential of a forward axis; 2–driveshaft; 3–вискомуфта; 4–differential of a back axis

At all-wheel drive models the torque from the engine is transferred to all wheels. As a result of operation of the automatic blocking device of intermediate differential there is an optimum distribution of engine capacity corresponding to a way of driving of the car and road conditions. In this regard all-wheel drive cars equally well behave at movement on highways and highways both in normal conditions, and in adverse, and also in cross-country conditions. The torque from the engine is transferred through a transmission and intermediate differential to differential of a forward axis, and from it — via the driveshaft — on differential of a back axis. At movement on a dry covering the torque is evenly distributed on all wheels of a lobby and a back axis. If wheels on one of axes lose coupling with the road and will appear on the verge of a proskalzyvaniye or pro-slipping, intermediate differential, without reducing torque size, automatically blocks wheels of this axis, transferring big size of a torque to the wheels of other axis having normal coupling with the road. Distribution of a torque to wheels at all-wheel drive models non-uniform also depends on extent of coupling of lobbies or back wheels with the road. The differential 4 (fig. 8.81) of the main reverse gear has the coupling of a free wheeling which disconnects a drive of back wheels when braking by the engine.

Reasons of the main malfunctions and ways of their elimination