The automatic transmission performs functions of smooth inclusion of coupling at start-off from the place and optimum gear shifting at the movement of the car.

Automatic boxes are equipped four operated to transfers for advance. The third, fourth transfers at the blocked coupling can mechanically join in a hydrotransformer round.

The main knots of the automatic transmission is the following:

– the gidrotrasformator transferring torque from the engine to the transmission. The blocking coupling allows to bypass the hydrotransformer and to mechanically switch the third and fourth transfers;

– planetary transmission. Is mechanical knot of the automatic transmission by means of which owing to continuous gearing of cogwheels and interaction of brakes and satellites it is possible to change transfer number practically without rupture of a stream of power;

– the oils operated by pressure multidisk couplings and brakes, and also a tape brake allow to determine necessary transfer numbers without rupture of a stream of power and to stop the rotating details. Unlike couplings, brakes are fixed on the transmission case;

– oil pump and radiator;

– couplings of a free wheeling for optimization of transfer of loading;

– main transfer;

– an electronic control system of hydraulics with the control unit for automatic transmissions. The control unit carries out gear shifting. The elements influencing operation of the control unit are the sensor of provision of a butterfly valve and sensors of frequency of rotation of the engine, frequency of rotation of an output shaft of the transmission, oil temperature in the transmission, etc.