General Repair Information
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 apply when carrying out vehicle repairs.
A number of generally applicable instructions for individual repair procedures, which are otherwise mentioned at various points in the Repair Manual, are summarized here under the topic components.
Components
Transmission
• Allocate bolts and other components according to transmission code. Refer to the electronic parts catalog ETKA.
• Thoroughly clean all connections and the surrounding area before disconnecting.
• When replacing or repairing a manual transmission, check the fluid level and fill if necessary.
• Use the transmission code to determine capacities and specifications.
Sealant
• Thoroughly clean housing joint surfaces before applying sealing compounds.
• Apply sealing paste (AMV 188 001 02) evenly and not too thick.
• Do not allow sealing compound to enter ventilation openings.
O-Rings, Shaft Seals, Seals
• O-rings, shaft seals and seals must be replaced.
• After removing gaskets and seals, always inspect the contact surfaces at housing or shaft for burrs resulting from removal, or for other signs of damage.
• Thoroughly clean housing joint surfaces before assembling.
• Before installing the shaft seals, lightly oil the outer circumference and fill the space between the sealing lips - arrow - halfway with sealing grease (G 052 128 A1).
• The open side of the shaft seals point toward the fluid to be sealed in.
• Press in new shaft seal, so that the sealing lip does not run on the same point as the sealing lip of the old shaft seal (use insertion depth tolerances).
• Lightly lubricate O-rings before installing to prevent them from being crushed when inserting.
• After replacing seals and sealing rings, check transmission fluid level and top off if necessary.
Fasteners
• Do not stretch the circlips.
• Installed position for some of the circlips: the circlip is narrower at the top. This makes it easier for the pliers to grab the circlip when removing and installing it.
• Always replace damaged or over-stretched circlips.
• Circlips must locate properly in the groove.
• Replace spring pins. Installed position: the slit - A - should be in line with the line of force- arrow -.
Bolts and nuts
• Loosen bolts and nuts in reverse of 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.
• Delicate parts must not be cross-threaded. Loosen and tighten in stages in a diagonal sequence.
• The tightening specifications stated apply to non-oiled nuts and bolts.
• Replace self-locking bolts and nuts.
• Clean threads of bolts that were applied with locking fluid using a wire brush. Apply locking fluid (AMV 185 101 A1) before reinstalling.
• Threaded holes into which self-locking bolts or bolts coated with locking fluid are screwed, must be cleaned (for example, with a thread tap). Otherwise there is a risk that the bolts will shear the next time they are removed.
Adjusting Shims
• Use a micrometer to measure the shims at several points. Tolerance variations make it possible to find the exact shim thickness required.
• Check for burrs and damage.
• Do not install shims which are damaged or not in perfect condition.
Mount
• Set needle bearings, ball sleeves and roller sleeves with the inscribed side (greater thickness) facing toward drift.
• Insert all the bearings in transmission with gear oil.
• Heat inner races of tapered roller bearings to approximately 100 °C (212 °F) with the inductive heat unit (VAS 6414) before installing. Press on to the stop when installing, so there is no axial clearance.
• Warm inner race for needle and roller bearings to 130 °C (266 °F) max.
• Do not interchange inner and outer bearing races with those from other bearings of the same size, bearings are paired.
• Tapered roller bearings installed on a shaft must be replaced as a set and use same make of bearings.
Gears, synchronizer hubs, selector gear inner races
• To install, heat gear wheel inner race to approximately 100 °C (212 °F) with (VAS 6414).
• Heat the gear wheels and synchronizer hubs to approximately 100 °C (212 °F) with the (VAS 6414) before installing. Press on to the stop when installing, so there is no axial clearance.
• Observe installation position.
Selector Gears
• After assembly, check selector gears of 1st through 6th gear for axial play of 0.15 to 0.50 mm and ease of movement.
Input Shaft
• If the surface of the input shaft is visibly damaged near the needle bearing in the dual mass flywheel - arrow -, then replace both the input shaft and the needle bearing. Refer to => [ Dual Mass Flywheel Needle Bearing, Sachs and LuK ] Dual Mass Flywheel Needle Bearing, Sachs and LuK.
• Check the input shaft near the bearing in the drive plate - arrow - for scoring. Replace the needle bearing in the drive plate if necessary.
Synchronizer Rings
• Do not interchange. When reusing synchronizer rings, always install to the same gear wheel.
• Check for wear and replace if necessary.
• Coat with gear oil before installing.
Check the Synchronizer Rings Coated with Molybdenum Grease.
• Clean the synchronizer ring. There must not be any oil on the friction surface.
• The friction surface of a intact molybdenum coated synchronizer ring looks graphite gray and slightly porous.
• Replace the synchronizer ring if the friction surface has shiny spots - A - or if the brass color base starts to show through.
Synchronizer Rings for 1st and 2nd Gears:
• Check coated friction surfaces - arrows 2 - from intermediate ring - B - for damage (flat areas, disintegrating areas or carbon layer).
• Check the inner friction surface - arrow 1 - of the synchronizer ring - A - and the outer friction surface - arrow 4 - of the inner race - C - for grooves and scoring.
• On inner races - C - with coated friction surfaces - arrow 3 -, check coating for damage (disintegrating carbon layer).
Damage on the Selector Gears and Locking Collars
• Damage to the synchronizer ring or gear wheel:
A Worn clutch spline camber on the synchronizer ring or gear wheel
• Compare: synchronizer ring or gear wheel not damaged:
B Undamaged clutch spline camber on the synchronizer ring or gear wheel
• Picture of damage on the locking collar:
C Worn longitudinal inner spline camber and the locking collar
• Comparison: locking collar not damaged:
D Undamaged longitudinal inner spline camber and the locking collar
• Synchronizer rings coated with carbon must be replaced together with the locking collar. The gear wheels must be replaced as well depending on the amount of wear.