Condensation of the crankcase neck and even the formation of individual drops in quantities not exceeding the norm specified below is not a sign of leakage. If there is abundant dripping, determine the condition of the seal.
Determining the condition of the seal
1. Place the car on a lift or inspection pit.
2. Clean the breather from dirt and check its condition.
3. After unscrewing the inspection plug, check the oil level in the bridge housing; if necessary, top up the oil level to normal.
4. Clean the gearbox housing neck from traces of oil and wipe dry.
5. Raise the rear axle and place it on stands.
6. Start the engine, engage direct gear and, at a speed of 90–100 km/h, warm up the oil to a temperature of 80–90°C (approximately 15 minutes).
7. With direct gear engaged, at a speed of 100 km/h, determine the amount of oil flowing out in 15 minutes.
Oil leakage exceeding 5 drops in 15 minutes is a sign of a faulty oil seal.
A damaged seal can be replaced without removing the gearbox from the vehicle, if no other gearbox parts need to be replaced.
Replacing the oil seal
1. Drain the oil from the rear axle housing.
2. Loosen the rear wheel mounting bolts; place chocks under the front wheels and lift the rear axle; release the parking brake and place the gear shift lever in neutral.
[The text is on the website: VazBook.ru]
3. Remove the wheels and brake drums.
4. Loosen the nuts securing the brake shield to the axle beam and use a pusher to remove the axle shafts from the differential box.
5. Disconnect the propeller shaft from the pinion flange and move the shaft to the side.
6. Check the torque of resistance to turning of the drive gear with a dynamometer and remember its value.
7. Holding the flange with a special key, unscrew the drive gear flange mounting nut and remove the flange with the washer.
8. Remove the pinion seal.
9. Install the new seal without tilting it, using a mandrel, having previously lubricated its working surfaces with LITOL-24 grease.
Attention! In order not to damage the seal when pressing it in, it is necessary to press it in not to the stop, but to a depth of 2 mm (permissible deviation "-0.3") between the end of the gearbox housing and the outer surface of the seal.
10. Install the flange with the washer on the drive gear and, holding it with a special key, tighten the flange mounting nut, periodically checking the torque of resistance to turning the drive gear with a dynamometer. If the initial torque of resistance to turning was 58.8 N cm (6 kgf cm) or higher, the new torque of resistance to turning should be 9.8–19.6 N cm (1–2 kgf cm) greater than the initial one. If the initial torque of resistance was less than 58.8 N cm (6 kgf cm), tighten the flange mounting nut until the torque of resistance is 58.8–88.2 N cm (6–9 kgf cm). If the torque of resistance to turning is exceeded when tightening the nut, disassemble the gearbox, replace the spacer sleeve with a new one, and then reassemble and adjust the gearbox (see subsection 7.4.7.6).
Assemble the rear axle in the reverse order of disassembly.