Adjusting Bevel Gear/Crown Wheel Pairing (Tooth Backlash)

Information 

• Always make sure a certain amount of backlash is present when tightening the screws. The drive shaft must not jam under any circumstances. 

1. Get ready to take measurements.
   1. 1.1. Read off the backlash on the crown wheel.
      1. Adjustment dimension E
      2. Backlash F
      3. Pairing number
         Fig 1: Identifying Crown Wheel Installation Dimension

         Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   2. 1.2. Fit drive and output shafts with tensioning plate and adjusting shims.

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

   3. 1.3. Fit gear wheel set and wheel housings. Then fit the front gear wheel set. → WM 343537 DISASSEMBLING AND ASSEMBLING TRANSMISSION (GT2, GT2 RS, GT3, GT3 RS & GT3 RS 4.0) .
      Fig 2: Identifying Assembly Sleeve On Output Shaft

      Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   4. 1.4. Screw on collar nut on output shaft.

      → Tightening torque: 300 Nm (222 ft. lb.) 

   5. 1.5. Install differential and fit side transmission cover with all the screws.

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

   6. 1.6. Screw on special tool Gauge Plunger VW 388  with special tool Adjustment Device VW 521/4  and set lever length to 91 mm -a-  .
      Fig 3: Identifying Adjustment Device For Final Drive

      Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   7. 1.7. Insert special tool Adjustment Device VW 521/4  into the differential using special tool Sleeve 9145  and clamp tightly.
   8. 1.8. Turn the differential in both directions a number of times to position the taper roller bearings.
   9. 1.9. Fit special tool Dial Gauge Holder VW 387  with dial gauge so that there is a right angle between the dial gauge axle and special tool Gauge Plunger VW 388  .
   10. 1.10. Fit special tool Retaining Device 9562  .
       Fig 4: Identifying Retaining Device

       Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   11. 1.11. Turn the crown wheel as far as it will go onto special tool Adjustment Device VW 521/4  using the clamping screw and set the dial gauge to 0.
2. Take the measurement.
   1. 2.1. Turn the crown wheel back and read off the circumferential backlash.
   2. 2.2. Repeat this measurement three more times.

      The crown wheel must be turned a further 90° before each measurement. The difference between the four measurements must not exceed 0.03 mm. Moreover, none of the measurements may deviate by more than 0.04 mm from the circumferential backlash noted on the crown wheel. If any of the specified dimensions is incorrect, the adjusting shims S1 and S2 must be replaced again.