Possible gearbox malfunctions (VAZ-2115)

Gearbox malfunctions, their causes and solutions:

Cause of malfunction	Method of elimination
Noise in the gearbox
Wear of gear teeth	Replace worn parts
Bearing wear	Replace worn bearings
Insufficient oil level	Add oil. Replace damaged or worn seals if necessary
Difficulty shifting gears
Incomplete clutch disengagement	See subsection "clutch"
Deformation of the control rod of the gearshift mechanism or the reaction rod	Straighten the rods or replace them
Loosening of the hinge or gear selector lever mounting screws	Tighten the screws (see "Transmission")
Incorrect adjustment of the gear shift drive	Adjust the gear shift drive
Wear or breakage of plastic parts in the gear shift drive	Replace the damaged part
Spontaneous gear disengagement
Damage or wear to the ends of the synchronizer teeth on the gear and clutch	Replace worn and damaged parts
Increased vibrations of the power unit on the supports due to cracks or delamination of the rubber on the rear supports	Replace damaged parts
Gear shifting due to improper adjustment of the gear shift drive or improper installation (tensioning) protective cover of the traction	Adjust the drive (see "Adjusting the gear shift drive") or adjust the traction cover
Noise ("crackling") when gears are engaged
Incomplete clutch disengagement	See subsection "Clutch"
Wear of the locking ring of the synchronizer of the engaged gear	Replace the locking ring
Oil leak
Wear of input shaft seals, constant velocity joint housings, gear selector rod or speedometer drive shaft seal	Replace the seals and gaskets
The crankcase or gearbox cover has become loose, or the sealant under the gearbox cover or between the gearbox housing and the clutch housing has become damaged, the drain plug has become loose	Replace the sealant, tighten the bolts and nuts, tighten the drain plug