When fogging the crankcase neck and when dripping, determine the condition of the stuffing box, for which:
- put the car on a lift;
- clean the breather from dirt, check its condition;
- having unscrewed the control plug, check the oil level in the axle housing; if necessary, bring the oil level to normal;
- clean the neck of the gearbox housing from traces of oil and wipe dry;
- unlock the center differential and set the stops under the front wheels;
- hang the rear axle and put it on stands;
- 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 (within approximately 15 minutes);
- 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 seal failure.
A damaged oil seal can be replaced without removing the gearbox from the vehicle, unless other gearbox parts need to be replaced.
The procedure for replacing the seal is as follows:
- drain the oil from the rear axle housing;
- loosen the nuts securing the rear wheels, put stops under the front wheels and hang out the rear axle; release the parking brake and place the gearshift lever in neutral;
- remove wheels and brake drums;
- unscrew the nuts securing the brake shield to the axle beam and use the ejector to remove the axle shafts from the differential box;
- disconnect the cardan shaft from the drive gear flange and move the shaft to the side;
- check with a dynamometer the moment of resistance to turning the drive gear and remember its value;
- holding the flange with a special wrench, unscrew the nut securing the drive gear flange and remove the flange with the washer;
- remove the drive gear seal;
- lubricate the working surface of the new oil seal with Litol-24 grease and press it with a mandrel into the gearbox housing to a depth of 2-0.3 mm between the end face of the gearbox housing and the outer surface of the oil seal;
- install the flange with the washer on the drive gear and, holding it with a special wrench, tighten the flange fastening nut, periodically checking the moment of resistance to turning the drive gear with a dynamometer.
If the initial torque was 58.8 Ncm (6 kgf cm) and higher, then the new moment of resistance to rotation should be 9.8... 19.6 N cm (1...2 kgf cm) more than the original. If the initial moment of resistance to rotation was less than 58.8 N cm (6 kgf cm), then tighten the flange fastening nut until a moment of resistance of 58.8... 88.2 N cm is obtained (6.9 kgf cm).
If, when tightening the nut, the moment of resistance to rotation is exceeded, then disassemble the reducer, replace the spacer sleeve with a new one, after which the reducer must be assembled and adjusted as indicated in chapter «Assembly and adjustment».
Assemble the rear axle in the reverse order of disassembly.