2015 Subaru WRX BaseFACTORY OEM SERVICE PROCEDURE

Front Differential Assembly: Installation

WARNING: This page is about a different variant/trim than selected.
  1. Install the front differential assembly to the converter case.
    NOTE: Be careful not to damage the inside of the case (especially the mating surface of the differential side retainers).
  2. Temporarily install the differential side retainers using ST.

    ST 18658AA020 WRENCH COMPL RETAINER

    Fig 1: Installing Differential Side Retainers Using Wrench COMPL Retainer (ST 18658AA020)
    G06654708Courtesy of SUBARU OF AMERICA, INC.
  3. Adjust the backlash of the front differential. <Ref. to ADJUSTMENT , Front Differential Assembly.>
  4. Inspect and adjust the tooth contact. <Ref. to ADJUSTMENT , Drive Pinion Shaft Assembly.>
  5. Remove the differential side retainers and install the O-rings and oil seals. <Ref. to SIDE RETAINER , ASSEMBLY, Front Differential Assembly.>
    NOTE:
    • Record how many turns were needed to remove.
    • Use new O-rings and oil seals.
  6. Install the differential side retainers using ST.
    NOTE: When attaching, turn the differential side retainer by the same number of turns it took to remove, and align the marks.

    ST 18658AA020 WRENCH COMPL RETAINER

  7. Install the lock plate.

    Tightening torque: 

    25 N.m (2.5 kgf-m, 18.4 ft-lb) 

    Fig 2: Identifying Front Differential Assembly Lock Plate
    G10268409Courtesy of SUBARU OF AMERICA, INC.
  8. Install the drive pinion shaft assembly. <Ref. to INSTALLATION , Drive Pinion Shaft Assembly.>
  9. Install the primary pulley, secondary pulley and variator chain. <Ref. to INSTALLATION , Primary Pulley and Secondary Pulley.>
  10. Install the transmission case. <Ref. to INSTALLATION , Transmission Case.>
  11. Install the forward clutch assembly. <Ref. to INSTALLATION , Forward Clutch Assembly.>
  12. Install the intermediate case. <Ref. to INSTALLATION , Intermediate Case.>
  13. Install the transfer reduction driven gear assembly. <Ref. to INSTALLATION , Transfer Reduction Driven Gear.>
  14. Install the center differential carrier. <Ref. to INSTALLATION , Center Differential Carrier.>
  15. Install the transfer clutch assembly. <Ref. to INSTALLATION , Transfer Clutch.>
  16. Install the rear drive shaft. <Ref. to INSTALLATION , Rear Drive Shaft.>
  17. Install the extension case. <Ref. to INSTALLATION , Extension Case.>
  18. Install the transmission harness. <Ref. to INSTALLATION , Transmission Harness.>
  19. Install the control valve body and oil pan. <Ref. to INSTALLATION , Control Valve Body.>
  20. Install the air breather hose. <Ref. to INSTALLATION , Air Breather Hose.>
  21. Install the transmission assembly to the vehicle. <Ref. to INSTALLATION , Automatic Transmission Assembly.>
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.