Rear Differential: Disassembly

To detect the real cause of trouble, inspect the following items before disassembling.

• Tooth contact and backlash between hypoid driven gear and drive pinion
• Hypoid driven gear runout on its back surface
• Total preload of drive pinion

1. Set the ST on vise and install the differential assembly to ST.

   ST 398217700 ATTACHMENT SET

   Fig 1: Installing Differential Assembly To ST

   Courtesy of SUBARU OF AMERICA, INC.
2. Remove the drain plug and filler plug, and drain the gear oil.
3. Remove the air breather cap.
   NOTE:

   • Do not attempt to replace the air breather cap unless necessary.
   • Whenever the air breather cap is removed, replace it with a new part.
     Fig 2: Air Breather Cap And Rear Cover

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4. Remove the bolts, and then remove the rear cover.
5. Remove the side retainer attachment bolts, set the ST to differential case, and extract the side retainers RH and LH with a puller.
   NOTE:

   • Side retainer shim of each side should be kept together with its mating retainer.
   • Keep the side retainers separate by attaching tags or in similar ways to make it possible to identify RH and LH sides.

   ST 398457700 ATTACHMENT

   Fig 3: Pulling Side Retainers RH And LH With Puller

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6. Pull out the differential case assembly from the differential carrier.
   NOTE: Be careful not to hit the teeth of hypoid driven gear against the differential carrier.
   Fig 4: Pulling Out Differential Case Assembly From Differential Carrier

   Courtesy of SUBARU OF AMERICA, INC.
7. When replacing the side bearing, remove the bearing cup from the side retainer using ST.

   ST 398527700 PULLER ASSY

   Fig 5: Removing Bearing Cup From Side Retainer Using ST

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8. Using the ST, remove the bearing cone.
   NOTE:

   • Do not attempt to disassemble the parts unless necessary.
   • Set the puller so that its claws catch the edge of the bearing cone.
   • Never mix up the RH and LH bearing races and cones.

   ST 18759AA000 PULLER ASSY

   Fig 6: Removing Bearing Cone Using ST

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9. Remove the hypoid driven gear by loosening hypoid driven gear bolts.
   Fig 7: Removing Hypoid Driven Gear Bolts

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10. Remove the pinion shaft lock pin from driven gear side using ST.

    ST 899904100 STRAIGHT PIN REMOVER

    Fig 8: Removing Pinion Shaft Lock Pin From Driven Gear Side Using ST

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11. Draw out the pinion mate shaft and remove pinion mate gears, side gears and thrust washers.
    NOTE: The gears should be marked or kept separated right and left, and front and rear as well as thrust washers.
    Fig 9: Side Gear, Pinion Mate Gear, Thrust Washer, Differential Case And Pinion Shaft

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12. Remove the self-locking nut while holding the companion flange with ST.

    ST 498427200 FLANGE WRENCH

    Fig 10: Removing Self-Locking Nut

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13. Extract the companion flange with a puller.
    Fig 11: Pulling Out Companion Flange With Puller

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14. Press the end of drive pinion shaft by using the ST, and remove the drive pinion shaft, rear bearing cone, preload adjusting spacer and washer.
    NOTE: Hold the drive pinion so as not to drop it.

    ST 398467700 DRIFT

    Fig 12: Pressing End Of Drive Pinion Shaft

    Courtesy of SUBARU OF AMERICA, INC.
15. Remove the rear bearing cone from drive pinion by supporting the cone with ST.
    NOTE: Place the replacer so that its center-recessed side faces the pinion gear.

    ST 398517700 REPLACER

    Fig 13: Removing Rear Bearing Cone From Drive Pinion

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16. Remove the front oil seal from differential carrier using ST.

    ST 398527700 PULLER ASSY

    Fig 14: Removing Front Oil Seal From Differential Carrier Using ST

    Courtesy of SUBARU OF AMERICA, INC.
17. Remove the pilot bearing together with the front bearing cone and spacer using the ST.

    ST 398467700 DRIFT

    Fig 15: Removing Pilot Bearing With Front Bearing Cone And Spacer Using ST

    Courtesy of SUBARU OF AMERICA, INC.
18. When replacing the bearings, use a brass bar to tap out the front bearing cup and rear bearing cup (in this order).
    Fig 16: Tapping Out Front Bearing Cup And Rear Bearing Cup

    Courtesy of SUBARU OF AMERICA, INC.