Differentials: Diagnosis Subaru Impreza GD/GC/GG

INSPECTION

Wash all the disassembled parts clean, and examine them for wear, damage, or other defects. Repair or replace defective parts as necessary.

1. Crown gear and drive pinion If abnormal tooth contact is evident, find out the cause and adjust to give correct tooth contact at assembly. Replace the gear if excessively worn or incapable of adjustment. If crack, score, or seizure is evident, replace as a set. Slight damage of tooth can be corrected by oil stone or the like.
2. Side gear and pinion mate gear Replace if crack, score, or other defects are evident on tooth surface. Replace if thrust washer contacting surface is worn or seized. Slight damage of the surface can be corrected by oil stone or the like.
3. Bearing Replace if seizure, peeling, wear, rust, dragging during rotation, abnormal noise or other defect is evident.
4. Thrust washers of side gear and pinion mate gear Replace if seizure, flaw, abnormal wear or other defect is evident.
5. Oil seal Replace if deformed or damaged, and at every disassembling.
6. Differential carrier Replace if the bearing bores are worn or damaged.
7. Differential case Replace if its sliding surfaces are worn or cracked.
8. Companion flange Replace if the oil seal lip contacting surfaces have flaws.

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Scheme 7

1. Disconnect ground terminal from battery.
2. Move selector lever or gear shift lever to "N".
3. Release the parking brake.
4. (Y) Loosen wheel nuts.
5. Jack-up vehicle and support it with sturdy racks.
6. Remove wheels.
7. Remove rear exhaust pipe and muffler. See «REMOVAL»(ref-177869-S08268736982005060700000), Rear Exhaust Pipe and «REMOVAL»(ref-177869-S37852780942005060700000), Muffler.
8. Remove front exhaust cover. (Scheme 2): Removing Front Exhaust Cover
9. Remove front cover of rear differential mount. (Scheme 3): Removing Front Cover Of Rear Differential Mount
10. Remove propeller shaft. CAUTION: When removing propeller shaft, pay attention not to damage the sliding surfaces of rear drive shaft (extension) spline, oil seal and sleeve yoke. NOTE: Prepare an oil can and cap since the transmission oil flows out from the extension at removing propeller shaft. Insert the cap into the extension to prevent transmission oil from flowing out immediately after removing the propeller shaft. (Scheme 4): Removing Propeller Shaft & Cap Extension Housing
11. Remove heat sealed cover.
12. Remove clamps and bracket of parking brake cable. (Scheme 5): Removing Clamps & Bracket Of Parking Brake Cable
13. Remove DOJ of rear drive shaft from rear differential. See «REPLACEMENT»(ref-177243-S24786067012005052500000), Rear Differential Side Oil Seal. (Scheme 6): Removing DOJ Of Rear Drive Shaft From Rear Differential
14. Secure rear drive shaft to rear crossmember using wire. (Scheme 7): Securing Rear Drive Shaft To Rear Crossmember Using Wire
15. Remove lower differential bracket.
16. Support rear differential with transmission jack.
17. Remove self-locking nuts connecting rear differential to rear crossmember.
18. Remove bolts which secure rear differential front member to body. Loosen bolt A first, then removal bolts B. NOTE: Support front member with the use of a helper to prevent it from dropping.
19. Remove bolt A.
20. While slowly lowering transmission jack, move rear differential forward and remove bolts from rear crossmember.
21. Remove front member from body.
22. Remove rear differential from body.

Wash all the disassembled parts clean, and examine them for wear, damage, or other defects. Repair or replace defective parts as necessary.

1. Crown gear and drive pinion If abnormal tooth contact is evident, find out the cause and adjust to give correct tooth contact at assembly. Replace the gear if excessively worn or incapable of adjustment. If crack, score, or seizure is evident, replace as a set. Slight damage of tooth can be corrected by oil stone or the like.
2. Side gear and pinion mate gear Replace if crack, score, or other defects are evident on tooth surface. Replace if thrust washer contacting surface is worn or seized. Slight damage of the surface can be corrected by oil stone or the like.
3. Bearing Replace if seizure, peeling, wear, rust, dragging during rotation, abnormal noise or other defect is evident.
4. Thrust washers of side gear and pinion mate gear Replace if seizure, flaw, abnormal wear or other defect is evident.
5. Oil seal Replace if deformed or damaged, and at every disassembling.
6. Differential carrier Replace if the bearing bores are worn or damaged.
7. Differential case Replace if its sliding surfaces are worn or cracked.
8. Companion flange Replace if the oil seal lip contacting surfaces have flaws.

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Scheme 13

Scheme 14

1. Disconnect ground terminal from battery.
2. Move selector lever or gear shift lever to "N".
3. Release the parking brake.
4. Remove oil drain plug, and drain gear oil. (Scheme 15): Removing Oil Drain Plug & Draining Gear Oil
5. Jack-up rear wheels and support the vehicle body with sturdy racks.
6. Remove propeller shaft from body. See «REMOVAL»(ref-177244-S25897615972005052500000), Propeller Shaft. CAUTION: Wrap metal parts with a cloth or rubber material to prevent damage from adjacent metal parts. (Scheme 16): Identifying Center Support Bearing
7. Remove self-locking nut while holding companion flange with ST. ST 498427200 FLANGE WRENCH (Scheme 17): Removing Self-Locking Nut From Drive Pinion While Holding Companion Flange
8. Extract companion flange with a puller. (Scheme 18): Extracting Companion Flange
9. Remove oil seal using ST. ST 398527700 PULLER ASSY (Scheme 19): Removing Front Oil Seal
10. Fit a new oil seal using ST. ST 498447120 OIL SEAL INSTALLER (Scheme 20): Installing New Front Oil Seal
11. Install companion flange.
12. Tighten self-locking nut within the specified torque range so that the turning resistance of companion flange becomes the same as that before replacing oil seal. CAUTION: Use a new self-locking nut. ST 498427200 FLANGE WRENCH Tightening torque: 181 N.m (18.5 kgf-m, 134 ft-lb) (Scheme 21): Tightening Self-Locking Nut
13. Reassembling procedure hereafter is the reverse of the disassembling.

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Scheme 21

1. Disconnect ground terminal from battery.
2. Move selector lever or gear shift lever to "N".
3. Release the parking brake.
4. Remove oil drain plug, and drain gear oil. (Scheme 22): Identifying Drain Plug
5. Jack-up rear wheels and support the vehicle body with sturdy racks.
6. Remove propeller shaft from body. See «REMOVAL»(ref-177244-S25897615972005052500000), Propeller. CAUTION: Wrap metal parts with a cloth or rubber material to prevent damage from adjacent metal parts. (Scheme 23): Identifying Center Support Bearing
7. Remove self-locking nut while holding companion flange with ST. ST 498427200 FLANGE WRENCH (Scheme 24): Removing Self-Locking Nut While Holding Companion Flange
8. Extract companion flange with a puller. (Scheme 25): Extracting Companion Flange
9. Remove oil seal using ST. ST 398527700 PULLER ASSY (Scheme 26): Removing Front Oil Seal
10. Fit a new oil seal using ST. ST 498447120 OIL SEAL INSTALLER (Scheme 27): Installing Front Oil Seal
11. Install companion flange.
12. Tighten self-locking nut within the specified torque range so that the turning resistance of companion flange becomes the same as that before replacing oil seal. ST 498427200 FLANGE WRENCH CAUTION: Use a new self-locking nut. Tightening torque: 188 N.m (19.2 kgf-m, 139 ft-lb) (Scheme 28): Installing Companion Flange
13. Reassembling procedure hereafter is the reverse of the disassembling.

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Scheme 33

1. Disconnect ground terminal from battery.
2. Move selector lever or gear shift lever to "N".
3. Release the parking brake.
4. Loosen both wheel nuts.
5. Jack-up the vehicle and support it with rigid racks.
6. Remove wheels.
7. Remove rear exhaust pipe and muffler. See «REMOVAL»(ref-177869-S08268736982005060700000), Rear Exhaust Pipe and «REMOVAL»(ref-177869-S37852780942005060700000), Muffler.
8. Remove the DOJ of rear drive shaft from rear differential. Remove the ABS sensor cable clamp and parking brake cable clamp from bracket. (Scheme 29): Removing ABS Sensor Cable Clamp & Parking Brake Cable Clamp From Bracket Remove the ABS sensor cable clamp from the trailing link. (Scheme 30): Removing ABS Sensor Cable Clamp From Trailing Link Remove the ABS sensor cable clamp and parking brake cable guide from the trailing link. (Scheme 31): Removing ABS Sensor Cable Clamp & Parking Brake Cable Guide Remove the rear stabilizer link. (Scheme 32): Removing Rear Stabilizer Link Remove the bolts which secure the trailing link to the rear housing. (Scheme 33): Removing Bolts From Trailing Link To Rear Housing Remove the bolts which secure the front and rear lateral link to the rear housing. (Scheme 34): Removing Bolts Which Secure Front & Rear Lateral Link To Rear Housing Remove the DOJ from the rear differential by using ST. CAUTION: When removing the DOJ from the rear differential, fit ST to the bolt as shown in figure so as not to damage the side bearing retainer. ST 208099PA100 DRIVE SHAFT REMOVER (Scheme 35): Removing DOJ From Rear Differential
9. Secure rear drive shaft to rear crossmember using wire. (Scheme 36): Securing Rear Drive Shaft To Rear Crossmember Using Wire
10. Remove side oil seal with ST. ST 398527700 PULLER ASSY (Scheme 37): Removing Side Oil Seal
11. Drive in a new side oil seal with ST. CAUTION: Apply chassis grease between the oil seal lips. ST 398437700 DRIFT (Scheme 38): Driving In A New Side Oil Seal
12. Insert the DOJ into rear differential. Install ST to rear differential. ST 28099PA090 SIDE OIL SEAL PROTECTOR (Scheme 39): Installing (ST) Into Rear Differential Insert the spline shaft until the spline portion is inside the side oil seal using ST. ST 28099PA090 SIDE OIL SEAL PROTECTOR (Scheme 40): Inserting Spline Shaft Until Spline Portion Is Inside Oil Seal Remove ST. ST 28099PA090 SIDE OIL SEAL PROTECTOR
13. Hereafter, re-assemble in reverse order of disassembly.

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Scheme 46

1. Disconnect ground terminal from battery.
2. Move selector lever or gear shift lever to "N".
3. Release the parking brake.
4. Loosen both wheel nuts.
5. Jack-up the vehicle and support it with rigid racks.
6. Remove wheels.
7. Remove rear exhaust pipe and muffler. See «REMOVAL»(ref-177869-S08268736982005060700000), Rear Exhaust Pipe and «REMOVAL»(ref-177869-S37852780942005060700000), Muffler.
8. Remove the DOJ of rear drive shaft from rear differential. Remove the ABS sensor cable clamp and parking brake cable clamp from bracket. (Scheme 41): Identifying ABS Sensor Cable Clamp & Parking Brake Cable Clamp Remove the ABS sensor cable clamp from the trailing link. (Scheme 42): Removing ABS Sensor Cable Clamp From Trailing Link Remove the ABS sensor cable clamp and parking brake cable guide from the trailing link. (Scheme 43): Removing ABS Sensor Cable Clamp & Parking Brake Cable Guide From Trailing Link Remove the rear stabilizer link. (Scheme 44): Removing Rear Stabilizer Link Remove the bolts which secure the trailing link to the rear housing. (Scheme 45): Removing Bolts Which Secure Trailing Link To Rear Housing Remove the bolts which secure the front and rear lateral link to the rear housing. (Scheme 46): Removing Bolts Which Secure Front & Rear Lateral Link To Rear Housing Remove the DOJ from the rear differential with tire lever. CAUTION: When removing the DOJ from the rear differential, fit tire lever to the bolt as shown in figure so as not to damage the axle shaft holder. NOTE: The side spline shaft circlip comes out together with the shaft. see scheme 190: Removing DOJ From Rear Differential Using Tire Lever
9. Secure rear drive shaft to rear crossmember using wire. see scheme 191: Securing Rear Drive Shaft To Rear Crossmember Using Wire
10. Remove oil seal with screwdriver. see scheme 192: Removing Side Oil Seal
11. Drive in a new side oil seal with ST. CAUTION: Apply chassis grease between the oil seal lips. ST 498447100 OIL SEAL INSTALLER see scheme 193: Installing New Side Oil Seal
12. Insert the DOJ into rear differential. CAUTION: Before inserting, replace the circlip at the end of the spline shaft with a new one. Install ST to rear differential. ST 28099PA090 SIDE OIL SEAL PROTECTOR see scheme 194: Inserting Side Oil Seal Protector (ST) Into Rear Differential Insert the spline shaft until the spline portion is inside the side oil seal. see scheme 195: Inserting DOJ Into Rear Differential Remove ST. ST 28099PA090 SIDE OIL SEAL PROTECTOR Completely insert DOJ into rear differential by pressing rear housing. NOTE: Make sure that oil seal lip is not folded over inward. see scheme 196: Pushing On Brake Drum To Completely Insert DOJ Into Rear Differential
13. Hereafter, re-assemble in reverse order of disassembly.