General information
The rear axle of the car has a semi-floating type hypoid design (the axis of the driving gear passes below the axis of the driven gear of the final drive). During cornering, the differential allows the outer wheel to spin faster than the inner wheel. The inner ends of the semi-axes are equipped with splines that engage with the splines of the hubs of the side gears of the differential, therefore, during cornering, the internal (by turning radius) the side gear also rotates slower than the outer gear. In this case, the planetary assembly begins to rotate inside the differential box. The differential is placed inside a cast housing equipped with a stamped cover and called the holder. The steel pipes of the axle shafts are pressed into the holder and scalded.
All-wheel drive models use a fully independent front suspension. The bridge is formed by a differential assembly and a pair of drive shafts equipped with internal and external constant velocity joints (SHRUS).
On some models, the rear axle is equipped with a limited-slip locking differential. Such a differential operates in the mode of a conventional planetary assembly until one of the wheels begins to slip. The assembly includes a pair of conical clutches that slow down the rotation of the differential box in a similar situation. The existing difference in the angular speeds of rotation of the wheels leads to an increase in the load on the satellites of the planetary assembly, which is transmitted through a conical clutch articulated with the axle shaft to the wheel engaged with the road surface.
Examination
Often, the suspicions of the failure of the components of one of the bridges turn out to be unfounded, and the source of the occurrence of the symptoms that take place lies in the violation of the proper functioning of completely different components of the car. Try to carefully assess the situation, one by one excluding all possible reasons for the refusal.
The occurrence of the following characteristic extraneous sounds is often mistakenly associated with a malfunction of the wheel drive:
- Noises caused by the friction of the tread on the road surface. Compare the noise background that occurs when driving on roads with different surfaces. In addition, road noise does not change when driving in gear and coasting;
- Noises emitted during the operation of the engine and gearbox are well conducted by the components of the transmission line engaged with these units. Try to remember the engine RPM at which the noises are at their most intense, then park the car, shift the transmission into neutral and accelerate the engine to the same RPM if the noises resume, so the wheel drive has nothing to do with them.
In view of the need to use special tools, it would be more correct to entrust the repair of the differential to the specialists of a car service. The following Sections of this Chapter describe the procedures for removing and installing axle shafts / drive shafts, replacing differential seals, replacing bearings and dismantling the entire wheel drive assembly in order to perform its refurbishment or replacement.
Note. When replacing the rear axle assembly, use the information contained in the identification code stamped on the front side of the right section of the crankcase assembly. The code determines the permissible load on the axle, the type of differential, the date and place of manufacture of the assembly.