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 general repair information that applies to several procedures throughout this information is summarized. They apply to this repair information.
Special Tools and Equipment
For a complete list of special tools used in the Repair information refer to Workshop Equipment and 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 brackets as well as parts that have been waxed. Contact surfaces must be free of wax and grease.
- For the correct bolts and other components. Refer to the Parts Catalog.
- Fill the transmission fluid when repairing the manual transmission.
Seals, Sealing Rings
Replace gaskets and oil seals.
After removing gaskets, examine contact surface on housing/shaft for burr resulting from removal or for other signs of damage.
- Thoroughly clean the separating surfaces and apply Sealant.
- Allocation. Refer to the Parts Catalog.
- Fill the space between the sealing lips -arrow- on the radial shaft seal halfway with Sealing Grease G 052 128 A1.
- The open side of the seals point toward the fluid to be sealed in.
- Lightly lubricate O-rings before installing to prevent them from being crushed when inserting.
Sealant
- Clean the housing separating surfaces thoroughly before applying the Sealant.
- Apply Sealant evenly and not too thick.
- For the correct allocation. Refer to the Parts Catalog.
- Sealant must not go into the bleed holes.
Fasteners
- Replace the circlips.
- Do not overstretch the circlips.
- The circlips must fit completely inside the groove.
- Replace the adapter sleeves. Installed position: slot is lengthwise to line of force.
Bolts and Nuts
- Always loosen or tighten bolts and nuts on covers and housings diagonally.
- Especially delicate parts, such as clutch pressure plates, must not be distorted. Loosen and tighten bolts and nuts in stages in a diagonal sequence.
- The tightening specifications stated apply to non-oiled nuts and bolts.
- Replace self-locking screws and nuts after removing them.
- Make sure the contact surfaces and visible surfaces on the nuts and bolts are waxed after assembling.
- Use a thread cutter 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.
- Please make sure that the thread pitch is correct so that the proper thread cutter is used during cleaning, and the thread does not get damaged.
Bearings
- Insert the bearings with transmission fluid.
- Install the new tapered roller bearings. It is not necessary to oil them.
- Install needle bearings with lettered side (thicker metal) racing the fitting tool.
- 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) with Inductive Heater VAS6414.
- Do not interchange inner and outer bearing races with those from other bearings of the same size, bearings are paired.
Adjusting Shims
- Measure the shims at several locations with a micrometer caliper. It is possible to measure the necessary shim thickness by the different tolerances.
- 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 wheel.
- 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 this intermediate ring on the outer friction surface -arrow 2- and inner friction surface -arrow 3- for >>grooves<<, >>wear grooves<< and >>blue coloring (from overheating)<<.
- Check taper of drive gear for >>grooves<< and >>scoring<<.
- Coat the synchronizing with transmission fluid and then install.
Toothed Gears, Synchronizer Hubs
- Clean before installing. Warm using the Inductive Heater VAS6414 to a maximum 100 °C (212 °F).
- Pay attention to the installed location.
Selector Gears
- After assembling, check the selector gears for minimum axial clearance and ease of movement.
Clutch Mechanism
Disconnect the battery ground cable. Refer to [For engine(s) CNNA, CCTA, CBFA] Battery, Starter, Generator, Cruise Control .
If the battery is to be reconnected: Refer to [For engine(s) CNNA, CCTA, CBFA] Battery, Starter, Generator, Cruise Control
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.