The transmission will transform the torque transferred from the engine in size and the direction. It is necessary for ensuring optimum speed and passability of the car, high profitability of operation of the engine and the movement of the car with a backing. Besides, the transmission separates the engine and transmission during a stop and the parking of the car, and also at its movement on inertia with the working engine.

All models with mechanical transmission are equipped with the five-speed transmission united in one knot with differential and the main transfer. The torque from the engine is transmitted through the transmission and the main transfer on differential which, in turn, distributes it between power shafts.

The five-step mechanical transmission is equipped with the mechanism of synchronization of all transfers.

Fig. 3.24. Cross section of the mechanical transmission of the Mazda 3 car: 1 – leading gear wheel of the 1st transfer; 2 – leading gear wheel of the 2nd transfer; 3 – leading gear wheel of the 3rd transfer; 4 – leading gear wheel of the 4th transfer; 5 – leading gear wheel of the 5th transfer; 6 – backing gear wheel; 7 – the conducted gear wheel of the 1st transfer; 8 – the conducted gear wheel of the 2nd transfer; 9 – the conducted gear wheel of the 3rd transfer; 10 – the conducted gear wheel of the 4th transfer; 11 – the conducted gear wheel of the 5th transfer; 12 – synchronizer coupling (backing gear wheel); 13 – intermediate gear wheel of a backing; 14 – differential

Fig. 3.25. The transmission in the block with the main transfer: 1 – epiploon (differential); 2 – car speedometer sensor; 3 – the mechanical transmission in the block with the main transfer; 4 – switching mechanism; 5 – transmission oil