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Differential System: Diagnosis Subaru Outback BR

Differentials & Drive Axles 9 illustrations ~1260 words

INSPECTION

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

  1. Hypoid driven gear and drive pinion If there is evidently an abnormal tooth contact, find out the cause and adjust until the teeth contact correctly. Replace the gear if there is an excessive worn or an incapable adjustment. If crack, cutout or seizure is found, replace the parts as a set. Slight damage of some teeth can be corrected by oil stone or the like.
  2. Side gear and pinion mate gear Replace if cracks, scoring or other defects are evident on the tooth surface. Replace if thrust washer contact surface is worn or seized. Slight damages of the surface can be corrected by oil stones or equivalent.
  3. Bearing Replace if seizure, peeling, wear, rust, dragging during rotation, abnormal noise or other defect is evident.
  4. Thrust washer of the side gear and pinion mate gear: Replace if seized, flawed, abnormally worn or having other defects.
  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 abnormally worn, burned, or cracked.
  8. Companion flange Replace if the oil seal lip contact surface shows cracking.

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

  1. Hypoid driven gear and drive pinion If there is evidently an abnormal tooth contact, find out the cause and adjust until the teeth contact correctly. Replace the gear if there is an excessive worn or an incapable adjustment. If crack, cutout or seizure is found, replace the parts as a set. Slight damage of some teeth can be corrected by oil stone or the like.
  2. Side gear and pinion mate gear Replace if cracks, scoring or other defects are evident on the tooth surface. Replace if thrust washer contact surface is worn or seized. Slight damages of the surface can be corrected by oil stones or equivalent.
  3. Bearing Replace if seizure, peeling, wear, rust, dragging during rotation, noise or other defect is evident.
  4. Thrust washer of the side gear and pinion mate gear: Replace if seized, flawed, abnormally worn or having other defects.
  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 abnormally worn, burned, or cracked.
  8. Companion flange Replace if the oil seal lip contact surface shows cracking.

Make sure that there is no leakage from front oil seal portion. If there is any leakage, replace the oil seal and inspect the propeller shaft.

Scheme 4

Scheme 4
Scheme 4

Scheme 5

Scheme 5
Scheme 5

Scheme 6

Scheme 6
Scheme 6

Scheme 7

Scheme 7
Scheme 7
  1. Disconnect the ground cable from battery.
  2. Shift the select lever or gear shift lever to neutral.
  3. Release the parking brake.
  4. Lift up the vehicle.
  5. Drain differential gear oil.
  6. Remove the rear exhaust pipe. 2.5 L SOHC model Ref. to «REMOVAL»(ref-371916-S24336289852010091900000) , Rear Exhaust Pipe. 2.5 L DOHC turbo model Ref. to «REMOVAL»(ref-371921-S14593980742010091900000) , Rear Exhaust Pipe. 3.6 L model Ref. to «REMOVAL»(ref-371938-S08736757402010091900000) , Rear Exhaust Pipe.
  7. Remove the heat shield cover.
  8. Remove the propeller shaft. Ref. to «REMOVAL»(ref-371909-S33653701722010091900000) , Propeller Shaft.
  9. Remove the self-locking nut while holding the companion flange with ST. ST 498427200 FLANGE WRENCH
  10. Extract the companion flange using the ST. ST 399703600 PULLER ASSY
  11. Remove the oil seal using ST or screwdriver. ST 398527700 PULLER ASSY
  12. Using the ST, install the oil seal. NOTE: Use a new oil seal. Apply differential gear oil to the oil seal lips. ST 498447120 INSTALLER
  13. Use a plastic hammer to install companion flange.
  14. Tighten the self-locking nut within the specified torque range so that the rotating resistance of companion flange becomes the same as that of before oil seal replacement. ST 498427200 FLANGE WRENCH NOTE: Use a new self-locking nut. Before installing self-locking nut, apply a sealing material to self-locking nut threads. SEAL MATERIAL: THREE BOND 1324 (Part No. 004403042) or equivalent Tightening torque: T-type 181.5 N.m (18.5 kgf-m, 133.9 ft-lb) VA-type 191 N.m (19.5 kgf-m, 140.9 ft-lb)
  15. Hereafter, reassemble in the reverse order of disassembly.
  16. Fill differential gear oil. Ref. to «DIFFERENTIAL GEAR OIL»(ref-371904-S29659730692010091900000) .

Make sure that there is no leakage from side oil seal. If there is any leakage, replace the oil seal.

Scheme 8

Scheme 8: REPLACEMENT
Scheme 8: REPLACEMENT

Scheme 9

Scheme 9
Scheme 9
  1. Remove the rear differential. Ref. to «REMOVAL»(ref-371904-S12303499152010091900000) , Rear Differential (T-type). Ref. to «REMOVAL»(ref-371904-S40825803462010091900000) , Rear Differential (VA-type).
  2. Remove the rear differential side oil seal using a ST or screwdriver wrapped with vinyl tape to prevent the side retainer from scratching.
  3. Using the ST, install the oil seal to the side retainer. T-type and VA2-type ST 398437700 DRIFT VA1-type ST 498447100 INSTALLER
  4. Install the rear differential. Ref. to «INSTALLATION»(ref-371904-S32937852732010091900000) , Rear Differential (T-type). Ref. to «INSTALLATION»(ref-371904-S33284519872010091900000) , Rear Differential (VA-type).

Scheme 10

Scheme 10: REMOVAL
Scheme 10: REMOVAL
  1. Disconnect the ground cable from battery.
  2. Lift up the vehicle.
  3. Support the rear differential using transmission jack, and then remove the rear differential front member.
  1. Check the rear differential front member for damage, bend and corrosion. If damage, bend or corrosion is excessive, replace the rear differential front member.
  2. Check the bushings of rear differential member for cracking, hardening and damage. If cracking, hardening or damage is excessive, replace rear differential front member.

Check the rear differential mount bushing for cracks, hardening or damage. If cracking, hardening or damage is excessive, replace rear differential mount bushing.

Scheme 11

Scheme 11: REPLACEMENT
Scheme 11: REPLACEMENT

Scheme 12

Scheme 12
Scheme 12
  1. Remove the rear differential. Ref. to «REMOVAL»(ref-371904-S12303499152010091900000) , Rear Differential (T-type). Ref. to «REMOVAL»(ref-371904-S40825803462010091900000) , Rear Differential (VA-type).
  2. Remove the rear differential mount bushing using ST1 - 7. From the SPECIAL TOOL ASSY (41399FG000), select the tool to be used for removal. Apply grease to the threaded portion on the shaft of ST1 and the bearing of ST4. Set the STs as shown in the illustration and tighten the ring of ST5 by hand until it stops. Secure the edge of the shaft of ST1 with a spanner, and tighten the nut of ST2 until the rear differential mount bushing comes out of the sub frame. CAUTION: Turning the shaft of ST1 may loosen the ST5 and damage a ST. Be sure to secure the ST1. ST1 41399FG090 SPECIAL TOOL SHAFT ST2 41399FG070 SPECIAL TOOL NUT ST3 41399FG050 SPECIAL TOOL SLEEVE ST4 41399FG080 SPECIAL TOOL BEARING ST5 41399FG060 SPECIAL TOOL RING ST6 41399FG010 SPECIAL TOOL A ST7 41399FG030 SPECIAL TOOL C
  3. Install the rear differential mount bushing using ST1 - 7. From the SPECIAL TOOL ASSY (41399FG000), select the tool to be used for installation. Set the STs as shown in the illustration and tighten the ring of ST5 by hand until it stops. CAUTION: Be careful not to install the ST7 in a wrong direction. Secure the edge of the shaft of ST1 with a spanner, tighten the nut of ST2, and press-fit the ST6 until it contacts the end face of sub frame. CAUTION: Turning the shaft of ST1 may loosen the ST5 and damage a ST. Be sure to secure the ST1. Be careful not to damage a ST by tightening the nut of ST2 further after the ST6 contacts the end face of sub frame. ST1 41399FG090 SPECIAL TOOL SHAFT ST2 41399FG070 SPECIAL TOOL NUT ST3 41399FG050 SPECIAL TOOL SLEEVE ST4 41399FG080 SPECIAL TOOL BEARING ST5 41399FG060 SPECIAL TOOL RING ST6 41399FG020 SPECIAL TOOL B ST7 41399FG040 SPECIAL TOOL D
  4. Install the rear differential. Ref. to «INSTALLATION»(ref-371904-S32937852732010091900000) , Rear Differential (T-type). Ref. to «INSTALLATION»(ref-371904-S33284519872010091900000) , Rear Differential (VA-type).
Symptom or troublePossible causeRemedy
1. Oil leakage(1) Worn, scratched, or incorrectly seated front or side oil seal. Scored, battered or excessively worn sliding surface of companion flange.Repair or replace.
(2) Clogged or damaged air breather.Clean, repair or replace.
(3) Loose bolts on differential spindle or side retainer, or incorrectly fitted O-ring.Tighten the bolts to specified torque. Replace the O-ring.
(4) Loose rear cover attachment bolts or damaged gasket.Tighten the bolts to specified torque. Replace gasket and apply liquid gasket.
(5) Loose oil filler or oil drain plug.Retighten and apply liquid gasket.
(6) Wear, damage or incorrect fitting of spindle, side retainer or oil seal.Repair or replace.
2. Seizure NOTE: Seized or damaged parts should be replaced, and also other parts should be thoroughly checked for any defect and should be repaired or replaced as required.(1) Insufficient backlash for hypoid gear.Readjust or replace.
(2) Excessive preload for side, rear or front bearing.Readjust or replace.
(3) Insufficient or improper oil used.Add recommended differential gear oil to the specified level.
3. Damage NOTE: Damaged parts should be replaced, and also other parts should be thoroughly checked for any defect and should be repaired or replaced as required.(1) Improper backlash for hypoid gear.Replace.
(2) Insufficient or excessive preload for side, rear or front bearing.Readjust or replace.
(3) Excessive backlash for differential gear.Replace gear or thrust washer.
(4) Loose bolts and nuts such as hypoid driven gear boltRetighten.
(5) Damage due to overloading.Replace.
4. Noises when starting or shifting gears NOTE: Noises may be caused by differential assembly, universal joint, wheel bearing, etc. Find out what is actually making noise before disassembling.(1) Excessive backlash for hypoid gear.Readjust.
(2) Improper tooth contact of hypoid gear.Readjust. (Drive pinion adjustment and backlash adjustment)
(3) Excessive backlash for differential gear.Replace gear or thrust washer.
(4) Insufficient preload for front or rear bearing.Readjust.
(5) Loose drive pinion nut.Tighten to the specified torque.
(6) Loose bolts and nuts such as side retainer attachment bolt.Tighten to the specified torque.
5. Noises when cornering(1) Damaged differential gear.Replace.
(2) Excessive wear or damage of thrust washer.Replace.
(3) Broken pinion mate shaft.Replace.
(4) Seized or damaged side bearing.Replace.
6. Gear Noise NOTE: Since noises from engine, muffler, transmission, propeller shaft, wheel bearings, tires, and body are sometimes mistaken for noises from differential assembly, be careful in checking them. Inspection methods to locate noises include coasting, accelerating, cruising, and jacking-up all four wheels. Perform these inspections according to the condition of trouble. When listening to noises, shift gears into four wheel drive and fourth speed position, trying to pick up only differential noise.(1) Improper tooth contact of hypoid gear.Readjust or replace hypoid gear set.
(2) Improper backlash of the hypoid gear.Readjust.
(3) Scored or chipped teeth of hypoid gear.Replace hypoid gear set.
(4) Seized hypoid gear.Replace hypoid gear set.
(5) Improper preload for front or rear bearings.Readjust.
(6) Seized, cut-away or chipped front or rear bearing.Replace.
(7) Seized, cut-away or chipped side bearing.Replace.
(8) Vibrating differential gear.Replace.
NOTE
Seized or damaged parts should be replaced, and also other parts should be thoroughly checked for any defect and should be repaired or replaced as required.
NOTE
Damaged parts should be replaced, and also other parts should be thoroughly checked for any defect and should be repaired or replaced as required.
NOTE
Noises may be caused by differential assembly, universal joint, wheel bearing, etc. Find out what is actually making noise before disassembling.
NOTE
Since noises from engine, muffler, transmission, propeller shaft, wheel bearings, tires, and body are sometimes mistaken for noises from differential assembly, be careful in checking them. Inspection methods to locate noises include coasting, accelerating, cruising, and jacking-up all four wheels. Perform these inspections according to the condition of trouble. When listening to noises, shift gears into four wheel drive and fourth speed position, trying to pick up only differential noise.

DIAGNOSTIC CHART

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