Audi A4

since 1994 release

Manual of the car

Audi A4
- Running gear
   Protection of passengers
   Full zinc covering
   Four-wheel drive
   Concepts of the all-wheel drive
   Distributive torsen-differential
   Dynamics of the movement on the dry road
   Maintenance instructions of the quattro cars
   Mechanism of blocking of differential
   Additional works on maintenance
   Motive compartment
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ System of an exhaust
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and channels of absorption
+ System of injection
+ Coupling
+ Transmission and main transfer
+ Suspension bracket of wheels and steering
+ Brakes
+ Wheels and tires
+ Electrotechnical equipment
+ System of ignition
+ Lighting
+ Alarm equipment
+ Tools and devices
+ Heating and ventilation
+ Body details
+ Salon
Search of malfunctions
Technical characteristics


Distributive torsen-differential

1 – the drive to the forward bridge;
2 – a hollow shaft (the drive to the transmission);
3 – differential case;
4 – the flange/driveshaft (for the drive
back bridge);
5 – worm of the drive of a back axis;

6 – cogwheel;
7 – axis of worm wheels;
8 – worm wheels;
9 – worm of the drive of the forward bridge.

The distributive (central) differential serves for alignment of forward and back transmission. (Differentials of a forward and back axis work irrespective of it.)

It is placed – outside not perceived as separate knot – behind on the mechanical transmission. Engineers speak: it is integrated.

The name торсен proceeds from firm on production of Gleason transmissions in which this differential was invented. Its name is derivative of the English letters Torque Sensing that means "feeling torque". Thus, it already consists in this concept the description of function as:

  • the differential transfers the increased force to the drive of that axis which has the best coupling with soil;
  • it occurs so effectively (it is caused by a design) that this axis can transfer bigger effort, than other axis by 3,5 times.
  • but at equally good properties of soil equivalent distribution of the drive to a forward and back axis is carried out, i.e. there is no preference of one axis caused by a design.

Principle of functioning

Work of torsen-differential is based on the principle of the worm drive and uses its fundamental principles:

  • the worm drive can be designed in such a way that will have high or low ability of blocking (blocking size in this case repeatedly increased force with which transfer has to be turned);
  • the size of value of blocking depends on a tilt angle of a worm, i.e. at a worm there is a lot of flat or few abrupt rounds;
  • example of a flat worm with high extent of blocking is the jack in which the knee which the worm affects lifts the car, but the car can never set in motion a knee at the expense of the weight.


At the expense of an intelligent arrangement in the sum of eight worm wheels and 12 gear wheels in combination with the differential case, a hollow shaft, a power shaft ahead and a power shaft the best performance of function about which it was told in the penultimate paragraph is behind reached.