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 applicable instructions for individual repair operations, which are otherwise mentioned at various points in the repair information, are summarized here. They apply to this repair information.
Contact Corrosion
- The housing components may be made of magnesium or of aluminum.
- Screws and other components which come into direct contact with the transmission have a surface coating adapted for this.
- Contact corrosion occurs when incorrect components (bolts, nuts, washers, etc.) are used. The housing components will get damaged.
Special Tools and Equipment
For a complete list of special tools used in this repair information refer to "Special Tools" at the end of each repair group.
Transmission
- Make sure that the alignment sleeves between the engine and transmission are positioned correctly when installing the transmission.
- Clean the contact surfaces when installing the brackets as well as any waxed components. Contact surfaces must be free of grease and wax.
- Check the transmission fluid level. Refer to TRANSMISSION FLUID LEVEL, CHECKING .
Gaskets and Seals
- Thoroughly clean the separation surfaces and apply sealing paste AMV 188 200 03.
- Apply the sealant paste evenly and not too thick.
- Replace gaskets and oil seals.
- After removing the gaskets, examine the contact surface on the housing/shaft for burrs resulting from removal or for other signs of damage.
- Before installing the radial shaft seals, lightly oil the outer circumference and fill the space between the sealing lips halfway with sealing grease for seal G 052 128 A1 -arrow-.
- The open side of the seal point toward the fluid to be sealed in.
- Check the transmission fluid level. Refer to TRANSMISSION FLUID LEVEL, CHECKING .
- Lightly lubricate O-rings before installing to prevent them from being crushed when inserting.
Fasteners
- Replace the circlips.
- Do not overstretch the circlips.
- The circlips must fit completely inside the groove.
- Replace the roll pins. Installed position: The slit is longitudinal to the direction of force.
Bolts and Nuts
- Always loosen or tighten bolts and nuts for covers and housings diagonally.
- Especially delicate parts, such as clutch pressure plates, must not be distorted. Loosen and tighten bolts and nuts in stages and in a diagonal sequence.
- The tightening specifications stated apply to non-lubricated nuts and bolts.
- Always replace self-locking nuts and bolts.
- Make sure the contact surfaces and visible surfaces on the nuts and bolts are waxed after assembling.
- Use a thread tap to clean all threaded holes containing self-locking bolts to remove any locking compound residue. Otherwise the bolts could shear the next time they are removed.
Bearings
- Install the new tapered roller bearings. It is not necessary to oil them.
- Install needle bearings with the lettered side (thicker metal) facing the fitting tool.
- Replace all the tapered roller bearings that are on the same shaft. Use tapered roller bearings from the same manufacturer.
- Heat the tapered roller bearing inner races to approximately 100 °C (212 °F) using the inductive heat unit VAS 6414 before installing. Press on until seated when installing, so there is no axial clearance.
- Do not interchange inner and outer bearing races with those from other bearings of the same size, bearings are paired.
Adjusting Shims
- Measure the adjusting shims at several locations with a mircometer caliper. Tolerance variations make it possible to find the exact shim thickness required.
- Check for burrs and damage.
- Only install perfect shims.
Synchronizer Rings
- Do not interchange them. When reusing synchronizer rings, always install them to the same gear.
- Check for wear and replace if necessary.
- Check the grooves -arrow 1- on the synchronizer ring -A- and the inner race for flat areas (grooves are worn).
- The coating on the synchronizer rings must not be damaged.
- If an intermediate ring -B- is installed, check the intermediate ring on the outer contact surface -arrow 2- and inner contact surface -arrow 3- for grooves, scoring and blue coloring (from overheating).
- Check the taper of the drive gear for grooves and scoring.
- Coat the synchronizing with transmission fluid and then install.
Gears
- Before pressing on, clean and warm to 100 °C (212 °F) Max. using the inductive heat unit VAS 6414.
Selector Gears
- After assembling, check the selector gears for minimum axial clearance and ease of movement.
Clutch
- Do not tilt the clutch pressure plate. Loosen and tighten diagonally and in steps.
- To reduce odor caused by a burnt clutch, thoroughly clean the clutch housing and the flywheel running surface with a clean cloth.