General Repair Information

The maximum possible care and cleanliness and proper tools are essential to ensure satisfactory and successful transmission repairs. The usual basic safety precautions also, naturally apply when carrying out vehicle repairs.

A number of generally valid instructions governing the various repair procedures - which used to be repeated several times throughout the service information- are summarized here .

Guided Fault Finding, OBD and Test Instruments 

• Before servicing the transmission, determine as best as possible the cause of the fault using the Vehicle Diagnostic Tester in the mode Guided Fault Finding  , Vehicle Self-Diagnosis  and Test Instruments  .

Oil, Environment and Disposal Regulations 

• Handle ATF, axle oil and other fluids with care.
• Dispose of the drained fluids properly.
• Follow the legal environmental and disposal regulations.
• Follow the information provided on oil packaging.

Special Tools and Equipment 

For a complete list of special tools used, refer to Special Tools and Workshop Equipment.

Transmission 

• Follow the rules for clean working conditions when working on the transmission, refer to CLEAN WORKING CONDITIONS, GUIDELINES .
• Do not run the engine or tow the vehicle when the center differential housing is removed or when there is no ATF.
• Check the following fluid levels after installation and, if necessary, fill: ATF in transmission (Refer to ATF LEVEL, CHECKING ), and gear oil in transmission (Refer to GEAR OIL ). Oil Capacity (Refer to CAPACITIES ) and specification .

O-Rings, Shaft Seals, Seals 

• O-rings, shaft seals and seals must be replaced.
• After removing gaskets, examine contact surface on housing/shaft for burr resulting from removal or for other signs of damage.
• Thoroughly clean housing joint surfaces before assembling.
• To install, thinly coat shaft seals along outer circumference and on sealing lip with ATF.
• Coat O-rings with ATF before inserting to prevent crushing rings during installation.
• Always only use approved ATF in the ATF area. Other types of lubrication cause faults to occur in the transmission hydraulics.
• The open side on the shaft seals faces the fluid to be sealed off.
• Press in new shaft seal, so that the sealing lip does not run on the same point as the sealing lip of the old shaft seal (use insertion depth tolerances).
• Check the following fluid levels after installation and, if necessary, fill: ATF in transmission (Refer to ATF LEVEL, CHECKING ), or gear oil in transmission (Refer to GEAR OIL ). Oil Capacity (Refer to CAPACITIES ) and specification

Bolts and Nuts 

• Loosen the bolts opposite the tightening sequence.
• Nuts and bolts which secure covers and housings should be tightened in steps according to the specified tightening sequence and method.
• Nuts and bolts which secure covers and housings should be loosened and tightened crosswise in stages if no tightening sequence is specified.
• Replace the self-locking nuts and bolts.
• Clean the threads on bolts that were installed with locking compound. After doing that, install the bolts with locking compoundAMV 185 101 A1.
• Threaded holes, in which self-locking bolts or bolts with locking compound were installed, must be cleaned (for example with a thread tap). Otherwise, there is a risk that the bolts may shear off when installing again.
• The tightening specifications stated apply to non-oiled nuts and bolts.

Fasteners 

• Do not overstretch the circlips.
• Replace damaged or stretched circlips.
• The circlips must fit completely inside the groove.

Bearings 

• Install needle bearings with lettered side (thicker metal) racing the fitting tool.
• Insert bearing with axle oil or ATF, depending on installation location.
• Do not interchange the outer or inner races for the same size bearings.
• Always replace the tapered roller bearings on one shaft together and use new bearings from a single manufacturer.

Adjusting Shims 

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