General Repair Information
General Repair Information
Carefulness, cleanliness and the correct tools are required for transmission repairs to be successful. The usual basic safety precautions apply when making vehicle repairs.
Some of the general information that is included with other procedures in this information are summarized here.
Contact Corrosion
• The transmission housing and clutch housing consist of a magnesium alloy.
• 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 transmission housing and clutch housing are damaged.
• Use the parts listed in the Parts Catalog.
Special Tools and Equipment
A list of special tools used in the repair procedure is listed at the beginning of each repair procedure. A complete list of tools is also listed at the end of each repair group under "Special Tools".
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.
• For the correct bolt allocation, refer to the Parts Catalog.
• Check the transmission fluid level. Refer to => [ Transmission Fluid, Checking ] Service and Repair.
Gaskets, Seals and O-rings
• Thoroughly clean the separation surfaces and apply sealing paste (AMV 188 200 03).
• Apply the sealing paste evenly and not too thick.
• Replace the 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 lubricate the outer circumference and fill the space between the sealing lips - arrow - halfway with sealing grease for seal (G 052 128 A1).
• The open side of the seal point toward the fluid to be sealed in.
• Check the transmission fluid level. Refer to => [ Transmission Fluid, Checking ] Service and Repair.
• Lightly lubricate O-rings before installing them to prevent them from being crushed when inserting.
Sealant
• Always thoroughly clean the separating surfaces on the housing before applying the sealing paste.
• Apply the sealing paste (AMV 188 200 03) evenly and not too thick.
• Do not allow any sealing paste to get into the ventilation holes.
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 the covers and housings diagonally.
• Especially delicate parts, such as a clutch pressure plate, must not be distorted. Loosen and tighten the 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 fluid residue. Otherwise the bolts could shear the next time they are removed.
• Please make sure that the thread pitch is correct so that the proper thread tap is used during cleaning, and the threads do not get damaged.
Bearings
• Install the new tapered roller bearings. It is not necessary to lubricate them.
• Install needle bearings with the lettered side (thicker metal) racing the installation 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 them. Press them onto the stop 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 micrometer. 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 taper of the drive gear for grooves and scoring.
• Coat the synchronizer rings with transmission fluid and then install them.
Gears
• Before pressing them on, clean and warm them 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 it diagonally and in small steps.
• To reduce odor caused by a burnt clutch, thoroughly clean the clutch housing and the flywheel running surface with a clean cloth.