Audi A4 models with all-wheel drive

General information

Four-wheel drive (Quattro models):

•    1 - engine;
•    2 - clutch; 
•    3 - manual gearbox; 
•    4 - gearbox input shaft; 
•    5 - power take-off shaft; 
•    6 - hollow shaft; 
•    7 - front differential; 
•    8 - Thorsen's differential; 
•    9 - cardan shaft; 
•    10 - rear power take-off shaft; 
•    11  - rear differential;
•    I - 1st gear;
•    II - 2nd gear;
•    III - 3rd gear;
•    IV - 4th gear;
•    V - 5th gear;
•    R - reverse;
•    A1 - main gear forward;
•    A2 - main gear reverse;
•    T - speedometer drive.

The AUDI A4 quattro has permanent all-wheel drive. To drive the rear wheels, the following are additionally used: a cardan shaft, a rear axle differential, two drive shafts for the rear wheels, as well as a Thorsen center differential.

The cardan shaft transmits torque from the front axle gearbox to the rear axle differential. From the rear axle differential, two drive shafts transmit power to the rear wheels. To compensate for different wheel speeds and torque distribution between the front and rear axles, depending on driving conditions, on models with all-wheel drive, a Torsen self-locking center differential is additionally installed, which can transmit variable torque to the front and rear wheels.

Features of towing

All wheel drive models can be towed with the front or rear wheels up.

Thus, however, the vehicle cannot be towed more than 50 km and the towing speed must not exceed 50 km/h. The car must be towed on a special conveyor.

Source:  http://carmanz.com/audi/a4-b6-2000-2004/6589-a420008-3-1.html