This article is a description of the device which is included in the transmission, connecting the synchronous electromotor with the wheel. This device consists of asymmetrical differential included in the transmission between the electromotor and the generator of the electromotor, which provides the electric current for its excitation winding. This design allows automatic change of the parameters in a wide range. Torque, depending on needs, can be repeatedly increased or decreased. Shaft speed also varies automatically multiply. Operation of the device is similar to the automatic gearbox. Parameters vary smoothly and optimally. At the same time, the electromotor rotational speed is constant and optimal.