2021 Subaru Outback BaseFACTORY OEM SERVICE PROCEDURE

Front Differential: Assembly

NOTE: When replacing the side bearing, always replace it together with inner race and outer race.
  1. Set the differential bevel pinion, thrust washer and differential bevel gear, and then install the pinion shaft.
    NOTE: Apply differential gear oil on the sliding portion of the differential bevel gear, thrust washer and pinion shaft.
    G13950884Courtesy of SUBARU OF AMERICA, INC.
  2. Measure the backlash between the differential bevel gear and differential bevel pinion, and select a thrust washer.
    1. Install the ST to the differential case.
      NOTE: The ST is a SUBARU genuine part.

      Preparation tool: 

      ST: Axle shaft (38415AA070)

    2. Measure the backlash between the differential bevel gear and differential bevel pinion using the magnet stand and dial gauge (lever type).
      NOTE:
      • Set the dial gauge (lever type) so that its needle contacts the differential bevel gear tooth.
      • When measuring, fix the differential bevel pinion in place.

      Specification: 

      0.13 - 0.18 mm (0.005 - 0.007 in)

      G13950885Courtesy of SUBARU OF AMERICA, INC.
    3. If the backlash is outside the standard
      1. Measure the thrust washer thickness.
      2. Referring to the measured values of backlash and thrust washer, select the thrust washer.
  3. Align the pinion shaft and differential case holes, and install a new spring pin from the driven gear side.
    G13950886Courtesy of SUBARU OF AMERICA, INC.
  4. Using the ST1, ST2 and a press, press-fit the side bearing inner race RH and LH.

    Preparation tool: 

    ST1: BUSHING 1-2 INSTALLER (499277100)

    ST2: SEAT (398497701)

    G13950887Courtesy of SUBARU OF AMERICA, INC.
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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.