During the operation of the gearbox, some unpleasant defects may occur, which are directly related to how maintenance is carried out and the driver’s driving style
Before you begin repairing the gearbox, you need to correctly identify the defect. Maybe this defect is not related to the gearbox at all.
In some cases, technicians begin to make mistakes at the gearbox, although the defect is in a completely different unit.
This is especially associated with such a defect as knocking in the transmission.
You need to carefully inspect and diagnose the entire transmission.
Possible gearbox malfunctions and ways to eliminate them
- Cause of malfunction
Remedy
Difficulty shifting gears
- Incomplete release of the clutch, presence of air in the hydraulic clutch release drive or lack of fluid in the clutch master cylinder
Bring the fluid level in the master cylinder reservoir to normal and bleed the clutch hydraulic system
- Loosening the locking bolts of the switching mechanism heads or forks
Tighten the locking bolts
- Burrs on the inner surface of the gear clutch teeth
Remove burrs
- The holes for the pins in the shift lever housing are broken
Replace the shift lever housing or repair it by boring the holes and pressing in the stepped pins
Disturbance in synchronization of gear shifting (shifting with a bang):
- Wear of the thread 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, grinding it to the surface of the corresponding gear until the contact surface is at least 80%
- Deformation of the locking ring (the ring does not lock on the cone when pressed and turned by hand)
Install a new blocking ring, grinding it against the surface of the corresponding gear until the contact surface is at least 80%.
Lapping paste KTTU-06283-76
Spontaneous shutdown 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 gear clutch teeth or wear of the spline teeth on the gears of the 1st, 2nd, 3rd, 5th gears, reverse and on the input shaft
Replace worn parts
- Loosening the clamp springs
Install springs with a load of (60+15) N (6+1.5) kg s when compressed to 10 mm
Gearbox noise:
- Bearing wear
Replace bearings
- Breakage of gear teeth
Replace damaged gears
- Wear of the working surface of gear teeth
Replace damaged gears
- Reduced oil level in the crankcase
Add oil to normal level
- The alignment of the crankshaft and clutch housing is broken
Check and restore alignment
Oil leak from gearbox:
- Wear of oil seals
Replace seals
- Breather is dirty or damaged
Clean the breather from dirt or replace it with a new one
- Leakage of plugs and crankcase plugs
Restore the tightness of the plugs
- Leakage of plugs and plugs of the gear shift mechanism
Restore the tightness of plugs and plugs
- Loosening of parts of the front cover, front and rear housings and gear lever housing
Tighten the bolts and nuts of the fastenings
- Damage to gaskets or presence of nicks on mating surfaces
Replace gaskets, clean out nicks and grind in mating surfaces
- Wear of the steel-babbit bushing of the rear crankcase
Replace the rear housing or press a steel babbit bushing 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
When all gears are engaged, no torque is transmitted to the driveshaft:
- Loose fit of gears on the intermediate shaft
Replace the intermediate shaft or weld the gear to the intermediate shaft
When engaging 2nd, 3rd or 5th gear, no torque is transmitted to the driveshaft:
- Loose fit of the 2nd, 3rd or 5th gear on the intermediate shaft
Replace the intermediate shaft assembly or weld the 2nd, 3rd or 5th gear gear to the intermediate shaft
