General Repair Information

Carefulness, cleanliness and the correct tools are required for transmission repairs to be successful. The usual basic safety precautions also, naturally apply when carrying out vehicle repairs.

A number of generally applicable instructions for individual repair operations, which are otherwise mentioned at various points in the Workshop Manual, are summarized here. They apply to this repair article.

Guided Fault Finding, OBD and Test Instruments 

• Before servicing the all wheel drive clutch, determine the cause of the damage as exact as possible using the Vehicle Diagnostic Tester in the "Guided Fault Finding" mode, the "Vehicle OBD" and the "Test Instruments".
• To prevent possible injury when performing measuring tests or test drives. Refer to SAFETY PRECAUTIONS .

-- Connect the Vehicle Diagnostic Tester and select function.

Special Tools and Equipment 

For a complete list of special tools used in the Repair Information refer to Workshop Equipment and Special Tools

Rear Final Drive 

• When replacing rear final drive, axle oil level and all wheel drive clutch fluid level must be checked and topped off, if necessary. Refer to GEAR OIL and HIGH-PERFORMANCE ALL WHEEL DRIVE CLUTCH OIL .
• Capacities. Refer to CAPACITIES .
• For the correct transmission fluid specification. Refer to the parts information.
• Clean the contact surfaces when installing the brackets as well as any waxed components. Contact surfaces must be free of grease and wax.

Shaft Seals, Sealing Rings, O-Rings, Seals 

• O-rings, gaskets and seals must be replaced.
• Once a shaft seal or gasket has been removed, check the contact surface on the housing or shaft for burrs and damage caused by the removal. Repair as necessary.
• Always clean separation surfaces.

Prior to installing 

• Before installing the shaft seal, lightly oil the outer circumference and fill the space between the sealing lips -arrow- halfway with Grease:G 052 128 A1  .
• Before installing the flange shaft/driveshaft shaft seals, lightly lubricate the outer circumference and the space between the sealing lips with High Performance All Wheel Drive Clutch Oil.
• The open side of the shaft seals point toward the fluid to be sealed in.

After installing: 

• Check the gear oil level in the rear final drive. Refer to GEAR OIL .
• Oil level in all wheel drive clutch, checking and filling. Refer to HIGH-PERFORMANCE ALL WHEEL DRIVE CLUTCH OIL .

Fasteners 

• Do not overstretch the circlips.
• Always replace damaged or stretched circlips.
• The circlips must fit completely inside the groove.
• Replace the adapter sleeves. Installed position: Slit -A- should in line with the line of force -arrow-.

Bolts and Nuts 

• Tighten and loosen the bolts and nuts for securing covers and housings in a diagonal sequence.
• Parts which are particularly sensitive to distortion must be kept straight when removing and installing; loosen or tighten diagonally in stages.
• The tightening specifications stated apply to non-oiled nuts and bolts.
• Always replace self-locking nuts and bolts.
• Clean the threaded holes for the self-locking bolts or for the bolts coated with locking fluid. Otherwise there is a risk that the bolts will shear the next time they are removed.
• Only wax all the contact surfaces on the threaded connection bolts and nuts after installing.

Bearings 

• Install needle bearings with lettered side (thicker metal) racing the fitting tool.
• Insert the bearings with transmission fluid.

Shims 

• Measure the shims at several locations with a micrometer caliper. Tolerance variations make it possible to find the exact shim thickness required.
• Check for burrs and damage.
• Only install perfect shims.