General Repair Instructions

General repair instructions
To ensure perfect and successful transmission repairs, the greatest care and cleanliness as well as the use of good and proper tools is essential. Obviously, the basic rules for safety are also applicable during repair work.
A number of generally valid instructions applicable for the various repair procedures -which were previously repeated a number of times at numerous places, are summarized here.

Transmission
- The transmissions are manufactured from aluminum and also from magnesium.

Identifying characteristics of magnesium transmission housing





The inscription Mg Al 9 Zn 1 can be found in vicinity of arrows -1- and -2- on transmissions manufactured from magnesium.
In addition, it can be determined with the transmission code letters whether a transmission is made of magnesium.
- The transmission housing, transmission cover and differential cover must all be of the same material.
- Bolts and other components, which have direct contact with the transmission casing have a surface which is matched to the transmission casing depending upon whether it is manufactured from aluminum or magnesium.
- On transmissions built of magnesium, the bolts must always be replaced on following bolted connections: transmission cover to transmission housing and final drive cover to transmission housing.
- If the incorrect components are used it will cause contact corrosion. The transmission will be damaged.
- Locate correct bolts and other components via the Parts catalogue.
- When installing the transmission, ensure that the dowel sleeves between the engine and transmission are correctly located.
- When changing a transmission fill with gear oil to the lower edge of the filler hole.
- Capacities and specifications.

Gaskets, sealing rings
- Thoroughly clean joint surfaces and apply sealant AMV 188 001 02.
- Apply sealant uniformly but not too thick.
- Renew "O-rings".
- Radial shaft oil seals.

Before installing:





Lightly oil outer edge and half-fill space between sealing lips -arrow- with grease G0521 28A1.
After installation:
Check transmission oil level; if necessary top up to lower edge of oil filler hole.

Locking devices
- Renew circlips.
- Do not overstretch circlips.
- Circlips must locate properly in the groove.





- Renew spring pins
Installation position: Slot longitudinal to line of force.

Bolts and nuts
- Tighten and loosen bolts and nuts for securing covers and housings in a diagonal sequence.
- Especially delicate parts, such as clutch pressure plates, must not be distorted. Loosen and tighten bolts and nuts in stages in a diagonal sequence.
- Tightening torques as specified are for un-oiled bolts and nuts.
- Renew self-locking bolts and nuts.

Bearings
- Install new roller bearings as delivered and do not apply additional lubrication.
- Install needle bearings with lettered side (thicker metal) towards fitting tool.
- Taper roller bearings fitted to one shaft must be replaced as a set. Use same make of bearings if possible!
- Heat inner races to approx. 100°C before installing.
- Do not interchange outer or inner races of bearings of the same size. The bearings are matched in pairs.

Shims
- Measure shims at several points 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. When reusing always fit to the same gear.
- Check for wear and replace if necessary.
- Coat with gear oil before installing.

Gear wheels
- Before installing clean and heat on a hot plate to approx. 100°C.
- Temperature can be checked with temperature tester VAG 1558.

Sliding gear wheels
- Check 1st through 5th sliding gear wheels for axial play of 0.15 to 0.35 mm or ease of movement following assembly.

Clutch control
- When removing transmission, remove clutch slave cylinder without opening pipe/hose system.
- To reduce the offensive odors in the event of a burnt clutch, the bell housing as well as the flywheel and transmission-side of the engine must be thoroughly cleaned.