General Repair Information
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.
Some general repair information that applies to several procedures throughout this service information is summarized here. They apply to this repair manual.
Selector Mechanism Emergency Release
If the battery has been disconnected or is discharged and the vehicle must be towed or pushed, it will be necessary to push the selector mechanism emergency release to shift the selector lever from "P" to "N". Refer to => [ Selector Mechanism, Performing Emergency Release ] Procedures.
Transmission
• Clean working conditions for the automatic transmission. Refer to => [ Clean Working Conditions ] Clean Working Conditions.
• Do not let the engine run or tow the vehicle when the oil pan is removed or when there is no Automatic Transmission Fluid (ATF) in the engine.
• With the transmission removed, secure the torque converter so that it cannot fall out.
• Check the installed dimension of the torque converter before installing the transmission. Refer to => [ Installed Dimension ] Removal and Replacement.
• When installing the transmission, make sure that the alignment bushings are correctly installed.
• When exchanging the automatic transmission or components, all fluid levels should be checked and corrected, as necessary. Also, all transmission fluid lines must be cleaned.
O-rings, Shaft Seals and Seals
• O-rings, shaft seals and seals must be replaced.
• After removing seals, examine the contact surface on the housing/shaft for burrs resulting from removal or for other signs of damage.
• Before installing a radial shaft seal, fill the space between the sealing lips - arrow - halfway with sealing grease for seal (G 052 128 A1).
• The open side of the shaft seal point toward the fluid to be sealed in.
• Before installing, lightly lubricate the shaft seal outer circumference and sealing lips with ATF or gear oil, depending on installed location.
• Lubricate the O-rings with ATF before inserting to prevent crushing them.
• Always only use approved ATF. Other types of lubrication cause faults to occur in the transmission hydraulics.
• Press in a 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).
• Replace paper gaskets, thoroughly clean sealing surfaces and completely remove old seals.
• After installing, check the relevant fluid levels and top off as necessary.
Bolts and Nuts
• Loosen bolts in the opposite direction of the tightening sequence if another sequence is not specified.
• Nuts and bolts which secure covers and housings should be loosened and tightened crosswise in stages if no tightening sequence is specified.
• The tightening specifications stated apply to non-lubricated nuts and bolts.
• Always replace the self locking nuts and bolts.
• Clean threads of bolts that were applied with locking fluid using a wire brush. Install the bolts with liquid locking fluid (AMV 185 101 A1).
• Threaded holes into which self locking bolts or bolts coated with locking fluid are installed, must be cleaned (for example, with a tap). Otherwise there is a risk that the bolts will shear the next time they are removed.
Circlips
• Do not overstretch the circlips.
• Always replace damaged or stretched circlips.
• The circlips must fit completely inside the groove.
Bearings
• Insert bearing with axle oil or ATF, depending on the installed location.
• Replace the transmission if any of the shift elements are scorched.
Control Modules, Electronic Components and Contacts
• Only touch electrical components after discharging static electricity on a grounded object, for example, by touching (skin contact) vehicle or vehicle lift.
• Connector contacts in connectors, control modules and electrical components must not be touched with the hands under any circumstances. They can be destroyed by static discharge.
Guided Fault Finding, On Board Diagnostic (OBD) and Test Instruments
• Try to determine the exact cause of the fault using the Guided Fault Finding, Vehicle Self-Diagnosis and Test Instruments before starting any work on the automatic transmission, refer to Vehicle diagnosis, testing and information system VAS 5051.