Contents: Description ↧ Inspection ↧
Description
1. Torque is transmitted to the rear axle via a semi-floated hypoid final drive (the pinion axis is located below the driven wheel axis). When turning the car, due to the presence of a differential, it is ensured that when the car enters a turn, the inner wheel, which rotates more slowly than the outer wheel, rotates its axle gear more slowly than the outer wheel rotates its axle gear. The satellites roll on the axle gear, which rotates more slowly, which allows the outer wheel and its axle gear to rotate at a higher speed.
2. As an option, the car can be equipped with a rear differential that locks when the wheels slip. The differential operates in normal mode until the torque on one of the wheels decreases. A differential with a lock is similar in design to a conventional differential, but has a special feature - on each side of the axle gears there are high-friction clutches that prevent one of the wheels from stopping while the other wheel is slipping; the torque between the wheels occurs due to the friction between the axle gears and the clutches, which have a splined fit on the axle shafts.
3. All-wheel drive models have fully independent front axle suspension. The design includes a differential and two axle shafts. Each axle shaft has an inner and outer constant velocity joint (CV joint). Since the differential is offset to the left (removed from the engine and combined with the transfer case), the left wheel is located closer to it than the right one. Therefore, a longer axle shaft is installed on the right side, which passes through the engine sump channel. On vehicles with controlled all-wheel drive (S4WD), the right drive shaft is engaged and disengaged via a fork and sleeve. This ensures that both axle shafts rotate at different angular velocities when the vehicle turns. On vehicles with automatic all-wheel drive, a differential of a similar design is used; the difference is that with an automatic drive the design does not provide for the presence of a fork and sleeve of the switching mechanism.
Inspection
4. It is often possible to mistakenly assume that the bridge has failed, while the problem actually occurred in another part of the vehicle. Before deciding to fail the bridge, carry out a series of checks to rule out any faults in other components.
5. When making a diagnosis, the following sources of characteristic noise should be taken into account:
- a) Often the noise produced by the road surface is mistaken for the noise produced by the bridge. Drive on different road surfaces and determine the source of the noise. The frequency and volume of noise produced by the road surface does not change depending on the load on the vehicle's transmission.
- b) Sometimes the noise coming from the tires when the car is moving is mistaken for the noise that could be coming from the axle. Tires that are worn to the limit or have low inflation pressure often make noise during operation and cause increased vibration of the vehicle while driving. Bridge noise changes under different driving conditions (coasting, acceleration, etc.), while the tire noise remains at the same level.
- c) Vibration and various noises emitted by the engine or gearbox and transmitted to the axle via the cardan transmission may serve as an erroneous basis for determining its failure. Note the engine speed at the highest noise level. Stop the vehicle, move the selector lever to neutral and accelerate the engine to the indicated speed. If the noise remains at the same level, a bridge malfunction should be ruled out as the cause of the noise.
6. It is not advisable to repair the differential yourself, as this requires the use of special equipment. This chapter describes the procedures for removing and installing axle shafts, replacing their seals and bearings, as well as the procedure for removing the differential entirely for subsequent repair at an auto repair shop or replacement.