Rear Differential: Disassembly

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

• Tooth contact of hypoid driven gear and drive pinion, and backlash
• 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

   Fig 1: Identifying Differential Assembly To Attachment 398217700

   Courtesy of SUBARU OF AMERICA, INC.
2. Drain the gear oil by removing plug.
3. Remove the air breather cap.
   NOTE:

   • Do not attempt to replace the air breather cap unless necessary.
   • Replace the air breather cap with a new one when removing it.
     Fig 2: Identifying Air Breather Cap

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4. Remove the bolts, and then remove the rear cover.
   NOTE: Remove it by tapping with plastic hammer.
   Fig 3: Identifying Rear Cover

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5. Keep the side bearing retainers RH and LH separately for easier reassembly. Remove the side bearing retainer attaching bolts, set the ST to differential case, and extract the bearing retainers RH and LH with a puller.
   NOTE: Each shim, which is installed to adjusted the side bearing preload, should be kept together with its mating retainer.

   ST 398457700 ATTACHMENT

   Fig 4: Identifying Bearing Retainers RH And LH Using Attachment ST 398457700

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6. Pull out the differential case assembly from differential carrier.
   NOTE: Be careful not to hit the teeth against the case.
   Fig 5: Pulling Out Differential Case Assembly From Differential Carrier

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7. When replacing the side bearing, remove the bearing cup from side bearing retainer using ST.

   ST 398527700 PULLER ASSY

   Fig 6: Identifying Bearing Cup From Side Bearing Retainer Using Puller Assy ST 398527700

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8. Extract the bearing cone with ST.
   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 bearing races RH and LH and cones.

   ST 18759AA000 PULLER ASSY

   Fig 7: Identifying Bearing Cone Using Puller Assy ST 18759AA000

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9. Remove the hypoid driven gear by loosening hypoid driven gear bolts.
   Fig 8: Removing Hypoid Driven Gear By Loosening Hypoid Driven Gear Bolts

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10. Drive out the pinion shaft lock pin from hypoid driven gear side (Model without LSD).
    NOTE: The lock pin is staked at the pin hole end on the differential carrier. Do not drive it out forcibly before removing the stake.

    ST 899904100 STRAIGHT PIN REMOVER

    Fig 9: Driving Out Pinion Shaft Lock Pin From Hypoid Driven Gear Side (Model Without LSD)

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11. Draw out the pinion mate shaft and remove pinion mate gears, side gears and thrust washers. (Model without LSD)
    NOTE: The gears should be marked or kept separated right and left, and front and rear as well as thrust washers.
    Fig 10: Identifying Pinion Mate Gears, Side Gears And Thrust Washers (Model Without LSD)

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12. Hold the companion flange with ST and remove the self-locking nut.

    ST 498427200 FLANGE WRENCH

    Fig 11: Removing Self-Locking Nut Using Flange Wrench ST 498427200

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13. Extract the companion flange with a puller.
    Fig 12: Extracting Companion Flange With Puller

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14. Press the end of drive pinion shaft and extract it together with rear bearing cone, pinion height Adjusting washer and washer.
    NOTE: Hold the drive pinion so as not to drop it.

    ST 398467700 DRIFT

    Fig 13: Identifying End Of Drive Pinion Shaft Drift ST 398467700

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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 14: Identifying Rear Bearing Cone From Drive Pinion Using Replacer ST 398517700

    Courtesy of SUBARU OF AMERICA, INC.
16. Remove the front oil seal from differential carrier using ST.

    ST 398527700 PULLER ASSY

    Fig 15: Identifying Front Oil Seal From Differential Carrier Using Puller Assy ST 398527700

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17. Remove the pilot bearing together with front bearing cone and collar using ST.

    ST 398467700 DRIFT

    Fig 16: Identifying Pilot Bearing, Front Bearing Cone And Collar Using Drift ST 398467700

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18. When replacing the bearings, hit out the front bearing cup and rear bearing cup in this order out of case using a brass bar.
    Fig 17: Hitting Out Front Bearing Cup And Rear Bearing Cup

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