Procedures
General Repair Information
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.
A number of generally applicable instructions for individual repair procedures, which are otherwise mentioned at various points in this repair information, are summarized here under the topic "Components". Refer to => [ Components ].
Special Tools and Equipment
• At the end of each repair group, is a list of the special tools used in that repair group.
Components
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.
• For the correct transmission fluid specification, refer to Fluid Capacity Tables.
• Fill the transmission fluid when repairing the manual transmission.
Sealant
• Clean the housing separating surfaces thoroughly before applying the sealant.
• Apply the sealing paste (AMV 188 200 03) evenly and not too thick.
Gaskets, Seals and O-rings
• Replace the gaskets, seals and O-rings.
• After removing gaskets and seals, always inspect the contact surfaces on the housing or shaft for burrs resulting from removal, or for other signs of damage.
• Before installing the seals, lightly oil 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.
• Press in the new seal, so that the sealing lip does not run on the same point as the sealing lip of the old seal (use insertion depth tolerances).
• Lightly lubricate O-rings before installing them in order to prevent them from being crushed when inserting.
• After replacing the seals and O-rings, check the transmission fluid level and fill as necessary. Refer to => [ Transmission Fluid, Checking and Filling ] Service and Repair.
Retainers
• Do not overstretch the circlip.
• Installed position for some of the circlips: The circlip is narrower on top and this shape matches its installed location. This makes it easier for the pliers to grab the circlip when removing and installing it.
• Always replace damaged or stretched circlips.
• The circlip must fit completely inside the groove.
• Replace the roll pin. Installed position: The slit - A - should be in line with the line of force - arrow -.
Bolts and Nuts
• Loosen the bolts and nuts opposite the tightening sequence.
• Bolts and nuts which secure covers and housings should be loosened and tightened diagonally and in steps if no tightening sequence is specified.
• 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 specification stated applies to non-lubricated nuts and bolts.
• Always replace self locking nuts and bolts.
• Use a wire brush to clean the threads of bolts that were installed with locking fluid. Next, use liquid locking fluid (AMV 185 101 A1) to install the bolts.
• Clean the threaded holes for the self locking bolts or for the bolts coated with locking fluid. Otherwise there is a risk that the bolts will shear the next time they are removed.
Bearings
• Insert all bearings in the transmission housing using transmission oil.
• 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.
• Replace all the tapered roller bearings that are on the same shaft. Use tapered roller bearings from the same manufacturer.
• Set the needle bearings, ball sleeves and roller sleeves with the inscribed side (greater thickness) facing toward the installation tool.
Adjusting Shims
• Measure the adjusting shims at several locations with a micrometer 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 as 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 outer friction surface - arrow 2 - and the inner friction surface - arrow 3 - for grooves and scoring.
• Check taper of the drive gear for grooves and scoring.
• Coat the synchronizer ring with transmission fluid and then install.
Toothed Gears, Synchronizer Hubs
• Heat the synchronizer hub 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 play.
• Heat the toothed gears 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 play.
• Pay attention to the installed location.
Selector Gears
• After installing, check 1st through 6th gear for minimal amount of axial clearance and for ease of movement.
Clutch Mechanism and Clutch
• When removing the transmission, remove the clutch slave cylinder without opening the lines.
• If the clutch slave cylinder is removed with the hydraulic line attached, do not press the clutch pedal. Otherwise the piston will be pressed out of the clutch slave cylinder.
• Do not tilt the clutch pressure plate. Loosen and tighten the bolts 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.