General Repair Information

The highest level of care and cleanliness along with tools that function properly are required to ensure a proper and successful transmission repair. Of course the general safety precautions also apply when carrying out repair work.

Some general repair information that applies to several procedures throughout this manual is summarized here. They apply to this Service Information.

Guided Fault Finding, OBD and Test Instruments

• Before beginning any repair work on the transmission, determine the exact cause of the damage using Diagnostic  in the Vehicle Diagnostic Tester.

Oil, Environmental and Disposal Regulations

• Handle ATF, gear oil and other fluids with care.
• Dispose of drained fluid properly.
• Follow the legal, environmental, and disposal regulations.
• Follow the instructions listed on the fluid packaging.

Special Tools

Refer to Workshop Equipment and Special Tools for a complete list of special tools used in the Service Information.

Transmission

• Follow the rules for clean working conditions when working on the transmission. Refer to GUIDELINES FOR CLEAN WORKING CONDITIONS .
• Do not run the engine or tow the vehicle when the center differential housing is removed or when there is no ATF.
• Check the fluid levels after installation and fill if necessary: Refer to ATF LEVEL, CHECKING for ATF in the transmission. Refer to GEAR OIL, CHECKING LEVEL for gear oil in the transmission. Refer to CAPACITIES  for capacities. Refer to the Parts Information for specifications.
• It is necessary to check the parking lock emergency release after performing any work on it or after removing and installing the transmission. Refer to EMERGENCY RELEASE FROM P .

O-Rings, Gaskets and Seals

• O-rings, gaskets and seals must always be replaced.
• After removing the seals, examine the contact surface on the housing or shaft for burrs resulting from removal or for other signs of damage.
• Thoroughly clean the housing separating surfaces before assembling.
• To install, thinly coat gaskets along outer circumference and on sealing lip with ATF.
• Coat the O-rings with ATF before inserting to prevent the rings from being crushed during assembly.
• Use only ATF in the ATF area. Other lubricants cause malfunctions in the hydraulic transmission control.
• The open side of the gaskets point toward the fluid to be sealed in.
• When installing the new shaft seal, make sure the sealing lip does not run on the same point as the sealing lip from the old seal (use press-in depth tolerance).
• Check the fluid levels after installation and fill if necessary: Refer to ATF LEVEL, CHECKING for ATF in the transmission. Refer to GEAR OIL, CHECKING LEVEL for gear oil in the transmission. Refer to CAPACITIES  for capacities. Refer to the Parts Information for specifications.

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 or method.
• Bolts or nuts for securing covers and housings should be loosened and tightened diagonally in stages if no tightening sequence is specified.
• Replace the self-locking nuts and bolts.
• Use a wire brush to clean the threads of the bolts that were installed with locking fluid. Then insert the bolts with Locking Fluid :AMV 185 101 A1  .
• Threaded holes used for self-locking bolts or bolts coated with locking fluid must be cleaned, for example with a thread tap. Otherwise there is the risk that the bolts could break off when they are removed again.
• Threads with stud holes must be cleaned before assembly.
• The tightening specifications given apply to un-oiled bolts and nuts.

Circlips

• Do not stretch the circlips.
• Replace damaged or stretched circlips.
• The circlips must rest at the bottom of the groove.

Bearings

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

Shims

• Measure the shims at several locations with a micrometer. Different shim thicknesses make it possible to select the required thickness precisely. Install two shims if necessary.
• Check for burrs or damage. Only install perfect shims.