ZIL vehicles and their modifications are equipped with a mechanical, five-speed gearbox with synchronizers (Fig. 1).

The use of synchronizers in the gearbox makes driving easier, ensures quiet gear shifting and increases the durability of gear couplings.
It should be borne in mind that the gearboxes are equipped with a worm 22 and a gear 59 for the speedometer drive, designed for a specific gear ratio in the rear axle.
Gearbox type: mechanical with five gears for moving forward and one in reverse
Gear ratios:
- - first gear 6.45
- - second gear 3.56
- - third gear 1.98
- - fourth gear 1.275.
- - fifth gear 1.00 (direct)
- - reverse gear 6.15
Maximum torque transmitted to the gearbox, N.m 410
Gear shifting is mechanical, with a rocker lever mounted on the box cover
Power take-off. From the reverse gear block
Maximum power of the power take-off, kW (hp) 22.08 (30)
Possible gearbox malfunctions
Cause of malfunction - Elimination method
Difficulty engaging all gears, reverse gear and first gear engage with a grinding noise
Incomplete disengagement of the clutch (the clutch “leads”) - Adjust the free play of the clutch release bearing coupling
Shifting gears with a bang and a grinding noise
Wear of synchronizer cone rings or locking chamfers of pins and carriage - Replace synchronizers
Self-switching gears on the go
Incomplete gear engagement due to a malfunction of the shift mechanism, wear of the fork grooves or loosening of the forks and levers - Eliminate malfunctions, replace worn parts
Gears are not included
Destruction of driven shaft gear bearings, breakage of pins or synchronizer clamps - Replace faulty parts - Replace synchronizers
Increased noise level during gearbox operation
Wear or breakage of gear teeth. Bearing failure - Replace faulty parts.
Oil leak from gearbox
Cuff wear or loss of elasticity
Increased pressure in the gearbox crankcase, leakage on sealing surfaces - Replace cuffs
Rinse the breather. Tighten fasteners, replace gaskets