A minor oil leak (sweating) from under the front bearing seal of the main gear is allowed, but if the gearbox and the bottom of the car above the main gear are heavily oiled, the seal should be replaced
The noise in the rear axle and, accordingly, the need for repairs can be determined based on the results of the following tests.
Test 1
Smoothly accelerate the car on a level road from a speed of 20 to 90 km/h.
At the same time, listen to the noise and note the speed at which it appears and disappears.
Release the gas pedal and listen to the car in engine braking mode.
Usually the noise appears and disappears at the same speeds, both during acceleration and deceleration.
Test 2
We accelerate the car to a speed of 100 km/h, move the gearshift lever to neutral, turn off the ignition and roll freely to a stop.
At the same time, we monitor the nature of the noise at various deceleration speeds.
In the first version, we tested the gearbox in acceleration and braking mode under the load created by the engine.
In the second - without it. If the noise is present only during the first test, it may be caused by the gearbox gears, pinion gear bearings, or differential.
If the noise appears in both cases, its source should be looked for elsewhere.
Test 3
Set the gearbox lever to neutral, start the engine, and gradually increase the crankshaft speed.
Compare the noise that occurs with the noises that were noticed earlier. If they are similar to the noises that occurred during the first test, this indicates that they are not coming from the gearbox.
Test 4
The noises detected during the first test and absent during subsequent tests are caused by the gearbox.
To confirm, lift the rear wheels, start the engine and engage fourth gear.
Make sure that the noises really come from the gearbox and not from other components or parts.
- Cause of malfunction
Remedy
Increased noise from the rear wheels
- Loose wheel mount
Tighten the wheel lug nuts
- Worn or damaged axle shaft ball bearing
Inspect the axle shaft and replace bearing
Constant increased noise when operating the rear axle
- The rear axle beam is deformed, the axle shaft bearings are damaged
Straighten the beam and check its dimensions, replace the axle shaft bearings
- The axle shafts are deformed and have an unacceptable runout
Replace the axle shafts with new ones
- Incorrect adjustment, damage or wear of the gearbox gears or bearings
Identify the gearbox malfunction, repair or replace the gearbox
- Wear or incorrect adjustment of the differential bearings
Remove the gearbox, repair and adjust
Noise when accelerating the car and braking with the engine
- Incorrect adjustment of the main gear mesh transmission
Adjust engagement
- Damaged axle shaft bearings
Replace bearings
- Insufficient oil
Restore oil level and check for leaks in seals or in rear axle beam
- Incorrect side clearance in final drive gear engagement
Adjust clearance
- Increased clearance in pinion bearings due to loose flange mounting nut or bearing wear
Adjust clearance, replace bearings if necessary
Noise when cornering
- Damaged axle shaft bearings
Replace bearings
Knock when starting to move car
- Wear of the hole for the satellite shaft in the differential case
Replace the differential case and, if necessary, the satellite shaft
- Loose rear suspension rod mounting bolts
Tighten the bolts
Oil leak
- Wear or damage to the pinion oil seal
Replace the oil seal
- Wear of the axle shaft oil seal, leading to oiling of the brake shields, drums and shoes
Check the axle shaft runout, beam deflection. Repair or replace damaged parts
- Loose rear axle gearbox housing mounting bolts, damage to the sealing gaskets
Tighten the bolts, replace the sealing gaskets