During the operation of the gearbox, some unpleasant defects may occur, which are directly related to how maintenance is carried out and the driving style of the driver

Before you start repairing the gearbox, you need to correctly install the defect. Maybe this defect is not related to the gearbox at all.

In some cases, the masters begin to sin at the checkpoint, although the defect is in a completely different node. This is especially due to such a defect as knocking in the transmission.

You need to carefully inspect and diagnose the entire transmission.

Possible gearbox malfunctions and how to fix them

- Cause of malfunction


Difficulty shifting

- Incomplete clutch disengagement, presence of air in the clutch release hydraulic actuator or lack of fluid in the clutch master cylinder

Upgrade the fluid level in the master cylinder reservoir and bleed the clutch hydraulic system

- Loosening of the locking bolts of the heads or forks of the shift mechanism

Tighten the locking bolts

- Burrs on the inner surface of the gear clutch teeth


- Broken holes for pins in shift lever housing

Replace shift lever housing or repair by boring holes and pressing stepped pins

Mismatched gear shifting (shifting):

- Thread wear of the conical surface of the synchronizer blocking ring

Remove the gearbox from the vehicle. Remove the front crankcase and check the gap between the blocking ring and the spur ring with a feeler gauge. If the gap is less than 0.3 mm, then install a new blocking ring, lapping it against the surface of the corresponding gear until a contact surface of at least 80% is obtained

- Deformation of the blocking ring (the ring does not stop on the cone when pressed and turned by hand)

Install a new blocking ring, lapping it against the surface of the corresponding gear until a contact surface of at least 80% is obtained.

Lapping paste KT TU-06283-76

Spontaneous disengagement of gears:

- Loosening the nuts securing the gearbox to the clutch housing or the bolts securing the gearbox housings

Tighten nuts or bolts

- Wear of the ends of the teeth of the gear couplings or wear of the teeth of the spline crown on the gears of the 1st, 2nd, 3rd, 5th gears, reverse and on the input shaft

Replace worn parts

- Loosening the springs of the clamps

Install springs with a load of (60+15) N (6+1.5) kg s with compression up to 10 mm

Noise in gearbox:

- Bearing wear

Replace bearings

- Breakage of gear teeth

Replace damaged gears

- Wear of the working surface of the gear teeth

Replace damaged gears

- Reduced oil level in the crankcase

Add oil to the correct level

- The alignment of the crankshaft and the clutch housing

Check and realign alignment

Oil leak from gearbox:

- Wear of oil seals

Replace oil seals

- Breather contamination or damage

Clean the breather from dirt or replace it with a new one

- Leakage of plugs and crankcase plugs

Restore cork seals

- Leakage of plugs and plugs of the gearshift lock

Restore the tightness of plugs and plugs

- Loose fastening of the parts of the front cover, front and rear crankcases and gear lever housing

Tighten bolts and nuts

- Damaged gaskets or nicks on mating surfaces

Replace gaskets, clean nicks and lap mating surfaces

- Wear of the steel-babbit bushing of the rear crankcase

Replace the rear crankcase or press it into it and bore it to a diameter of 3 + 0.015 mm coaxially with the hole for the ball bearing within no more than 0.05 mm steel-babbit bushing

When all gears are engaged, torque is not transmitted to the cardan shaft:

- Loose fit of the gears on the intermediate shaft

Replace the layshaft or weld the pinion to the layshaft

When you turn on the 2nd, 3rd or 5th gear, no torque is transmitted to the cardan shaft:

- Loose fit of the 2nd, 3rd or 5th gear on the countershaft

Replace the layshaft assembly or weld the 2nd, 3rd or 5th gear to the layshaft