Front Differential Assembly: Adjustment

1. Disassemble the front differential. Refer to REMOVAL  , Front Differential Assembly.
2. Select a differential washer from the table and install.
   Fig 1: Washer Thickness Chart

   Courtesy of SUBARU OF AMERICA, INC.
3. Adjust until the specified value is obtained.
   1. Standard backlash: 0.13 - 0.18 mm (0.0051 - 0.0071 in) 

Adjust backlash by turning the holder in right side case.

ST 499787000 WRENCH ASSY

Fig 2: Adjusting Backlash By Turning Holder In Right Side Case

Courtesy of SUBARU OF AMERICA, INC.

Fig 3: Identifying Backlash Changes By 0.05 Mm (0.020 In)

Courtesy of SUBARU OF AMERICA, INC.

1. Adjust until the tooth contact is correct.
2. Check and adjust the tooth contact with following.

• Tooth contact

  Checking item: Tooth contact pattern is slightly shifted toward to toe side under no-load rotation. [When loaded, contact pattern moves toward heel.] 

  Fig 4: Checking & Adjust Tooth Contact

  Courtesy of SUBARU OF AMERICA, INC.
• Face contact

  Checking item: Backlash is too large. 

  Contact pattern

  Fig 5: Identifying Checking Item: Backlash Is Too Large

  Courtesy of SUBARU OF AMERICA, INC.

  Corrective action: Reduce thickness of drive pinion shim in order to bring drive pinion close to driven gear.

  Fig 6: Identifying Corrective Action

  Courtesy of SUBARU OF AMERICA, INC.
• Flank contact

  Checking item: Backlash is too small. 

  Contact pattern

  Fig 7: Identifying Contact Pattern

  Courtesy of SUBARU OF AMERICA, INC.

  Corrective action: Increase thickness of drive pinion shim in order to move drive pinion away from driven gear.

  Fig 8: Increasing Thickness Of Drive Pinion Shim In Order To Move Drive Pinion Away From Driven Gear

  Courtesy of SUBARU OF AMERICA, INC.
• Toe contact (Inside end contact)

  Checking item: Contact area is small. 

  Contact pattern

  Fig 9: Identifying Contact Pattern

  Courtesy of SUBARU OF AMERICA, INC.

  Corrective action: Increase thickness of drive pinion shim in order to bring drive pinion close to driven gear.

  Fig 10: Increasing Thickness Of Drive Pinion Shim In Order To Bring Drive Pinion Close To Driven Gear

  Courtesy of SUBARU OF AMERICA, INC.
• Heel contact (Outside end contact)

  Checking item: Contact area is small. 

  Contact pattern

  Fig 11: Identifying Heel Contact (Outside End Contact)

  Courtesy of SUBARU OF AMERICA, INC.

  Corrective action: Reduce thickness of drive pinion shim in order to move drive pinion away from driven gear.

  Fig 12: Reducing Thickness Of Drive Pinion Shim In Order To Move Drive Pinion Away From Driven Gear

  Courtesy of SUBARU OF AMERICA, INC.