Most often, the owners of the VAZ-2105 complain about the hum or howl coming from the rear of the car.
There are four main reasons for extraneous sounds in the rear:
1. Excessive wear in the main pair as a result of prolonged operation or low oil exploitation.
2. Excessive wear in bearings as a result of prolonged maintenance or low-oil exploitation.
3. There is a lack of crew-tail of the tail.
4. Disruption of reductor after repair.
A professional specializing in the repair of gearboxes can tell by the sound that it is one of the above that happened with the gearbox.
All these changes in the mechanism require the major repair of the gearbox, except in the case of a rolling tail. In case of accumulation of wear, attempts to use thicker oil, additives and other "people's means" may only delay the repair.