General Repair Information: Notes

• 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.
• Some general repair information that applies to several procedures throughout this service information is summarized here. They apply to this service information.

Guided Fault Finding, On Board Diagnostics (OBD) and Test Instruments

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

The Guided Functions  button and the Guided Fault Finding  button offer various functions, refer to WORKING WITH TESTER .

Special Tools and Equipment 

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

Transmission 

• Do not run engine or tow the vehicle when the oil pan is removed or when there is no transmission fluid.
• Always clean the connection locations and the area around them before loosening.
• During installation, make sure that the alignment bushings are fitted correctly.

O-Rings, Gaskets, Seals 

• O-rings, gaskets and seals must be replaced.
• Seals are also called shaft seals.
• After removing gaskets, examine contact surface on housing/shaft for burr resulting from removal or for other signs of damage.
• Clean the housing separating surface thoroughly before assembling.
• Lightly coat the seals with ATF along outer circumference and along the sealing lip.
• Coat O-rings with transmission fluid before inserting to prevent crushing rings during installation.
• Do not use any other lubricants in the gear oil area. Otherwise there is a danger of malfunction of the transmission hydraulics.
• The open side of the seals point toward the fluid to be sealed in.
• When installing the new shaft seals, make sure the sealing lip does not run on the same point as the sealing lip of the old seal (use insertion depth tolerances).
• Follow the guidelines for clean working conditions, refer to GUIDELINES FOR CLEAN WORKING CONDITIONS .

Fasteners 

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

Adjusting Shims 

• Measure the shims at several locations with a micrometer caliper. It is possible to measure the necessary shim thickness by the different tolerances.
• Check for burrs and damage.
• Only install perfect shims.

Bolts and Nuts 

• Loosen the bolts opposite the tightening sequence.
• Nuts and bolts which secure covers and housings should be loosened and tightened diagonally and in steps if no tightening sequence is specified.
• Replace the self-locking nuts.
• Use a wire brush to clean the threads of bolts that were screwed in with locking compound. Install the bolts with Locking Fluid AMV 185 101 A1.
• The tightening specifications stated apply to non-oiled nuts and bolts.