Attention: Do not allow excessive stress and damage to the anthers of the CV joints of the drive shafts; do not bend the shaft to the stop; do not allow the drive shafts to fall, as this can damage the inside of the CV joint boots without any external signs of this.
The cars in question, depending on the version, have a drive either only on the front wheels (FWD models), or on all wheels (AWD models). On FWD models, torque is transmitted to the front wheels through the drive shafts from the manual transmission / DSG differential (see illustrations 1.2ab,d of Chapter 6).
The variable angle of inclination of the drive shafts is implemented by means of constant velocity joints (SHRUS), placed in protective corrugated anthers. The outer CV joints are attached to the wheel hubs. The drive shafts are the same length, so an intermediate shaft is installed between the right drive shaft and the transmission of the FWD models, fixed on the side of the drive shaft in an intermediate support.
Organization of all-wheel drive
On AWD models, a bevel gear is mounted on the front differential on the right, providing power take-off to rotate the rear wheels. The rear wheels are driven from an angle drive through a propeller shaft, 4th generation Haldex clutch, rear final drive with differential and rear drive shafts (see illustration 1.2c of Chapter 6).
The Haldex clutch is integrated into the rear final drive and can be replaced separately. The oil supply to the Haldex clutch and the final drive is via two separate oil circuits. For lubrication and cooling, two types of oil are used to meet the relevant requirements. Mixing or mixing these oils will result in severe damage to the Haldex clutch or final drive.
The procedure for checking and correcting the level of corner gear, Haldex clutch and final drive fluids is described in Section 4 of Chapter 1. Haldex clutch fluid should be changed in accordance with the maintenance schedule (see Sections 3 and 22 Chapters 1).
The main advantages include:
- control of the pump supply depending on the need;
- clutch control depending on driving style;
- acceleration of the torque increase due to advanced control;
- compatibility with ABS and ESP systems;
- independence from road conditions.
The data for identifying the rear final drive is indicated on its crankcase (see illustration 1.1).
1.1 Part number (A, "0BR"), code (IN, "KMS") and production date (WITH, "090908") rear final drive
The distribution of traction force between the axles with the help of the Haldex coupling is carried out in multiple ways, depending on the movement parameters (traction, load, efficiency, dynamics, forced idling, maneuvering). The following components are involved in the electronic control of all-wheel drive:
- the engine control unit "J623" (crankshaft speed, torque and power signals);
- instrument cluster control unit (wheel circumference signal);
- ABS/ESP control unit "L04" (brake and wheel speed signals);
- steering angle sensor;
- all-wheel drive control unit "J492" (torque detection).
Features of carrying out repair work on the rear final drive
1. When installing support brackets or waxed components, clean the mating surfaces of wax and grease.
2. Thoroughly clean the split surfaces and apply sealant AMV 188 200 03 to them.
3. Apply sealants evenly and not too thick.
4. Before installing radial seals (oil seals) half fill the space between the sealing lips with grease G052 128 A1 (see illustration 2.4 of chapter 6).
5. The open side of the stuffing box must face the process fluid.
6. Lightly lubricate the O-rings before installation so as not to damage them during installation.
7. After replacing the seal, check and correct the fluid level (see chapter 1).
8. Loosen and tighten the threaded fasteners of covers and casings in a diagonal pattern.
9. Torques shown apply to unlubricated threaded fasteners.
10. Replace self-locking nuts and bolts.
11. Remove any remaining thread locking compound from the threaded holes with a cleaning tool before inserting the self-locking bolts into the holes. Otherwise, there is a risk of shearing the bolts when they are subsequently removed.
12. Install new tapered roller bearings as supplied; do not apply additional lubricant.
13. Install needle bearings so that the side with the letters (thicker metal layer) facing the installation tool.
14. Tapered roller bearings mounted on a single shaft must be replaced as an assembly.
15. Before installation, heat the inner races of the bearings to approximately 100°C.
16. Do not interchange outer and inner races of bearings of the same size, as they are in pairs.