On the input shaft of the mechanical gearbox, 5 forward and one reverse are made. All forward drive gears are in constant mesh with their respective driven gears. Part of the gears is made in one piece with the shafts, others are mounted on needle bearings, which ensure silent rotation of the gears. When the gear lever is in neutral position, no torque is transmitted from the drive shaft to the driven shaft.
The gears rotate freely as long as the shift lever is in the neutral position. The gears are engaged by moving the synchronizer sliding clutch, as a result of which the gear is rigidly connected to the gearbox shaft. To do this, each shaft has its own synchronizers for the corresponding gears.
In order for the gears to mesh with each other, their number of revolutions must be equalized. This is achieved with the help of synchronizers, which, before the gears engage, come into contact with each other and, by friction, compare the number of revolutions of the shafts.
The number of revolutions of the first three gears is less than the number of revolutions of the engine, the number of revolutions of the fourth gear (straight) the same as the motor shaft. In fifth and sixth gears, the speed increases compared to the engine speed. For reverse gear, an additional gear is used, which changes the direction of rotation of the shaft. To prevent the possibility of accidentally engaging reverse gear while moving forward, the vehicles are equipped with a shift mechanism in which reverse gear is traditionally engaged by first pressing the lever down.
Use the shift knob to select the desired gear. The shift handle is connected to the gearbox by means of rods, fork pushers and levers.