Measuring The Differential (Total Shim Thickness S1 And S2)

Information 

• The chamfers of the adjusting shims are pointing towards the housing. 

Information 

• The differential must not be turned while taking measurements as this would give incorrect measurement results. 

Information 

• The pretension of the taper roller bearing in this transmission is always 0.40 mm. 

Information 

• The crown wheel must be adjusted again if the transmission housing, side cover, taper roller bearing for the differential, differential housing or ring gear and pinion shaft are replaced. 

1. Get ready to take measurements.
   Fig 1: Identifying Differential Shim Locations

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   1. 1.1. Insert one -S1-  shim and one -S2-  shim, with a thickness of 2.5 mm each, in the differential and fit taper roller bearing.
   2. 1.2. Insert transmission in the housing and turn it several times.
   3. 1.3. Fit side transmission cover without shaft sealing ring and screw in all screws.

      → tightening torque: 25 Nm (19 ft. lb.) 

   4. 1.4. Fit special tool Adjustment Device VW 521/4  opposite the crown wheel side (S2 side) in the differential.
   5. 1.5. Position special tool End Plate VW 385/17 -B-  on the differential.
      Fig 2: Identifying Special Tool End Plate On Differential

      Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   6. 1.6. Secure special tool Dial Gauge Holder VW 387  with dial gauge and special tool Dial Gauge Extension VW 385/56 -A-  on the housing.
2. Take the measurement.
   1. 2.1. Set dial gauge to 0 with 2 mm pretension.
   2. 2.2. Press differential up fully using special tool Adjustment Device VW 521/4  .
   3. 2.3. Read off the amount of play on the dial gauge.

      Example: 0.75 mm

   4. 2.4. The total thickness of shims S1 and S2 is calculated from the total of the already inserted shims plus the measured value plus the specified bearing pretension of the taper roller bearing.

      Example: 

      5.00 mm + 0.75 mm + 0.40 mm = 6.15 mm = S1 + S2