Procedures
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 procedures, which are otherwise mentioned at various points in this repair information, are summarized here.
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 bolts and other components, refer to the Parts Catalog.
• For the correct capacities, refer to => [ Codes Letters, Transmission Allocation and Capacities ] Codes Letters, Transmission Allocation and Capacities.
• Fill the transmission fluid when repairing the manual transmission.
O-rings, Gaskets, Seals and Sealant
• Clean the housing separating surfaces thoroughly before applying the sealant.
• Apply sealant (AMV 188 200 03) evenly and not too thick.
• Replace the O-rings, seals and gaskets.
• 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 - arrow - halfway with grease (G 052 128 A1).
• The open side of the seal point toward the fluid to be sealed in.
• When installing the new shaft seal, make sure 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 to prevent them from being crushed when inserting.
• After replacing the seals and sealing rings, check the transmission fluid level and fill if necessary. Refer to => [ Transmission Fluid, Checking and Filling ] Service and Repair.
Fasteners
• Do not overstretch the circlips.
• Always replace damaged or stretched circlips.
• The circlips must fit completely inside the groove.
• Replace the roll pins. Installed position: Slit - A - should be in line with the line of force - arrow -.
Bolts and Nuts
• Loosen the bolts and nuts opposite the tightening sequence.
• Nuts and bolts which secure covers and housings should be loosened and tightened diagonally and in steps if no tightening sequence is specified.
• Especially on delicate parts, such as clutch pressure plates, they 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 the self locking nuts and bolts.
• Clean the threads of bolts that were installed using locking fluid with a wire brush. Install the bolts using locking fluid (AMV 185 101 A1).
• Clean the threaded holes for the self locking bolts or for the bolts installed with locking fluid. Otherwise there is a risk that the bolts will shear the next time they are removed.
Bearings
• Install needle bearings with the lettered side (thicker metal) race the fitting tool.
• Install all the bearings in the transmission using transmission fluid.
• Replace all the tapered roller bearings that are on the same shaft. Use tapered roller bearings from the same manufacturer.
• To install, heat the bearing inner races to approximately 100 °C (212 °F) using the inductive heat unit (VAS 6414).
• Do not interchange outer and inner bearing races with those from other bearing of the same size. The bearings are paired.
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 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 outer friction surface - arrow 2 - and the inner friction surface - arrow 3 - for grooves and scoring.
• Check the taper of the drive gear for grooves and scoring.
• Coat the synchronizer ring with transmission fluid and then install.
Gear Wheels, Synchronizer Hubs and Needle Bearing Inner Races
• Warm the needle bearing inner races to approximately 100 °C (212 °F) using the (VAS 6414).
• Heat the synchronizer hub to approximately 100 °C (212 °F) using the (VAS 6414) before installing. Press on until seated when installing so there is no axial play.
• Heat the gears to approximately 100 °C (212 °F) using the (VAS 6414) before installing. Press on until seated when installing, so there is no axial clearance.
• 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
• When removing the transmission, remove the 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 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.