Repair Information: Notes
For the transmission to be repaired successfully and to function correctly, the greatest possible care and cleanliness and proper tools are required. The usual basic safety precautions also, naturally apply when carrying out vehicle repairs.
A series of generally applicable notes for individual repair procedures have been gathered here which otherwise would be listed several times in many places in the repair information. They apply to this repair information.
Guided Fault Finding, On Board Diagnostic (OBD) and Test Instruments
- Try to determine the exact cause of the fault using "Guided Fault Finding", "OBD" and "Test Instruments" before servicing the transmission using a vehicle diagnostic tester.
Special Tools and Equipment
For a complete list of special tools used in the Repair Information., refer to Service Net under Special Tools and Equipment.
Transmission
- Do not run engine or tow the vehicle when the oil pan is removed or when there is no transmission fluid.
- When replacing a transmission, always check the transmission fluid level and add if necessary. Refer to TRANSMISSION FLUID, CHECKING AND FILLING ; capacities, refer to CAPACITIES , specifications
- During installation, make sure that the alignment bushings are installed correctly.
Seals, O-rings, Shaft Seals
- Replace the seals, O-rings and the shaft seals.
- After removing seals, check sealing surfaces on housing or shaft for burrs resulting from removal or damage.
- Replace the seals, completely remove old seal and clean sealing surfaces.
- Coat the O-rings with gear oil before inserting to prevent crushing them.
- Coat the radial shaft seals lightly with oil on the outer circumference and fill the space between the sealing lip -arrow- halfway with sealing grease. For the correct sealing grease
- 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 shaft seals point toward the fluid to be sealed in.
- Follow the rules for clean working conditions, refer to CLEAN WORKING CONDITIONS .
- After installing, check the gear oil level and fill if necessary, refer to TRANSMISSION FLUID, CHECKING AND FILLING or check the axle oil level and fill if necessary AXLE OIL LEVEL, CHECKING AND FILLING .
Fasteners
- Be careful not to overstretch the locking rings. Replace them if necessary.
- The circlips must fit completely inside the groove.
Bolts and Nuts
- Loosen the bolts opposite the tightening sequence.
- 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.
- Use a wire brush to clean the threads of bolts that were screwed in with locking compound. Then install the bolts with locking compound. For the correct locking compound
- The tightening specifications stated apply to non-oiled nuts and bolts.
- Tightening specification with additional torque: After tightening to the specification, these bolts must be tightened further to the specified angle, for example, 40 Nm + 90° (90° corresponds to a quarter turn).