1)Ring gear carrier (housing) was changed.
2)Final drive cover was replaced.
3)New differential bearings have been used.
4) Transaxle was changed to reverse rotation. (Ring gear placed on opposite side of pinion gear.)

RING AND PINION ADJUSTMENT

The ring and pinion gears are matched as a set. You can note that they have corresponding identification numbers. These ID numbers can be found on the outside edge of the ring gear. On the pinion shaft they are etched between third and fourth gear. Older models have the numbers etched on the pinion gear face. These numbers denote the following: correct center distance as measured between the face of the pinion gear and the centerline of the ring gear and its carrier, they identify the ring and pinion as a set, and also give the gear ratio.
Example: You might find the following on the ring gear - 28. 5454 both etched and 833 stamped. The 28 is the pinion - ring gear deviation from normal (or ideal) center distance measured in hundredths of millmeters. The 5454 is the matching number for the pinion shaft. (Identify them as a set.) The 833 is the drive ratio 8:33 count it, 8 teeth on the pinion, and 33 on the ring gear. The .28mm reading holds true only for this particular set of ring and pinion. It was determined at the factory where the gear set was run-in on a machine to find correct tooth contact. Now you see why they are a set and both must be replaced if either show excessive wear, cracks or chips. The .28mm (once again this is an example) measurement is to be added to the ideal or normal measurement given at 58.70mm - therefore corrected distance should be 58.98mm from the pinion gear face to the ring gear and carrier center line. (See photo) If you are using the same ring and pinion gears, and the same main case - your original shim will give you this correct measurement, unless the ring and pinion gears show signs of excessive wear, no adjustment is necessary.
If you are using a new main case and/or pinion and ring gear, you'll
have to adjust the pinion to its corrected position by use of shims.
This is the proceedure for finding out just what size shim you need.
1)With the pinion and main shaft assembled into their bearing case, install the bearing case, using a gasket but no pinion shaft shim, into the main case.
2)Tighten the pinion bearing retainer bolts to 36 ft. lbs.
3)Insert the differential side bearings fully into the side plates.
4) Mount the right side plate (the one without the clutch cable guide) with a gasket. Tighten nuts to 22 ft. lbs.

The following steps are done using VW tool number 289d with a dial indicator fitted with a 5mm stem. This operation can be carried out using a reworked ring gear carrier but before you attempt to make one, be sure you fully understand what is being done. The tolerance for the measurement you must make is .0008" or .02mm, therefore care must be taken.

5)Place the dial indicator into the VW 289d instrument and place on guage block.

6)Adjust the dial to zero and preload it (.40" or I.Omm).
7)Place instrument into the transmission case and through the right side plate bearing.
8)Put left side cover plate onto case using a new gasket. Tighten nuts.
9)Observing the dial indicator through the center hole of the instrument rotate the stem against the pinion face and watch for highest reading.