Differential System (Except Sti): Other Subaru Impreza GH

REAR DIFFERENTIAL

When replacing a rear differential assembly, select the correct one according to the following table.

Note. Using a different rear differential assembly will cause the drive train and tires to drag or emit abnormal noise.

REAR DIFFERENTIAL SPECIFICATION CHART

REAR DIFFERENTIAL SPECIFICATION CHART

REAR DIFFERENTIAL GEAR OIL

Recommended gear oil

GL-5 (75W-90)

Scheme 161

SERVICE DATA

DRIVE PINION BEARING PRELOAD SPECIFICATION CHART

ADJUSTING PARTS

LENGTH SPECIFICATION CHART

THICKNESS SPECIFICATION CHART

Scheme 162

Tightening torque: N.m (kgf-m, ft-lb)

T1: 10.5 (1.1, 7.7)

T2: 29.5 (3.0, 214)

T3: 49 (5.0, 36.2)

T4: 103 (10.5, 76.0)

T5: 181.5 (18.5, 134.0)

Scheme 163

Tightening torque: N.m (kgf-m, ft-lb)

T1: 50 (5.1, 36.9)

T2: 70 (7.1, 51.6)

T3: 110 (11.2, 81.1)

CAUTION

1. Wear appropriate work clothing, including a cap, protective goggles and protective shoes when performing any work.
2. Remove contamination including dirt and corrosion before removal, installation or disassembly.
3. Keep the disassembled parts in order and protect them from dust and dirt.
4. Before removal, installation or disassembly, be sure to clarify the failure. Avoid unnecessary removal, installation, disassembly and replacement.
5. Vehicle components are extremely hot after driving. Be wary of receiving burns from heated parts.
6. Use SUBARU genuine gear oil, grease. Do not mix gear oil, grease, etc. of different grades or manufacturers.
7. Be sure to tighten fasteners including bolts and nuts to the specified torque.
8. Place shop jacks or rigid racks at the specified points.
9. Apply gear oil onto sliding or revolving surfaces before installation.
10. Before installing the O-ring or snap ring, apply a sufficient amount of gear oil to avoid damage and deformation.
11. Before securing a part on a vise, place cushioning material such as wood blocks, aluminum plate, or cloth between the part and the vise.
12. Avoid damaging the mating surface of the case.

GENERAL TOOL

GENERAL TOOL CHART

AT MODEL

For front differential of automatic transmissions. Ref. to FRONT DIFFERENTIAL ASSEMBLY .

MT MODEL

For front differential of the manual transmission. Ref. to FRONT DIFFERENTIAL ASSEMBLY .

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1. Set the vehicle on a lift.
2. Disconnect the ground cable from battery.
3. Shift the select lever or gear shift lever to neutral.
4. Release the parking brake.
5. Loosen the wheel nuts.
6. Lift up the vehicle.
7. Remove the wheels.
8. Drain the differential gear oil. Ref. to «REPLACEMENT»(ref-357279-S38327633232010031100000) .
9. Remove the rear exhaust pipe and muffler. Non-turbo model Ref. to «REMOVAL»(ref-357254-S32999093642010031100000) , Rear Exhaust Pipe. Ref. to «REMOVAL»(ref-357254-S17169301122010031100000) , Muffler. Turbo model Ref. to «REMOVAL»(ref-357260-S02665767832010031100000) , Rear Exhaust Pipe. Ref. to «REMOVAL»(ref-357260-S20286020412010031100000) , Muffler.
10. Remove the heat shield cover.
11. Remove the propeller shaft. Ref. to «REMOVAL»(ref-357249-S12597038342010031100000) , Propeller Shaft.
12. Remove the DOJ of rear drive shaft from rear differential. Remove the ABS wheel speed sensor cable from the clamp. Remove the bolts which secure the rear stabilizer link to the rear lateral link. Remove the bolts which secure the shock absorber to the rear lateral link. Remove the bolts which secure the rear lateral link to the housing. Remove the bolts which secure the trailing link to the housing. Remove the DOJ from the rear differential by using ST. NOTE: When removing the DOJ from the rear differential, fit the ST to the bolts as shown in the figure so as not to damage the side retainer. ST 28099PA100 DRIVE SHAFT REMOVER
13. Suspend the rear drive shaft to the rear crossmember using wire.
14. Remove the rear differential front member.
15. Support the rear differential with the transmission jack.
16. Remove the self-lock nuts which hold the rear differential to the rear crossmember.
17. Remove the dynamic damper assembly. (5 door AT model)
18. While slowly lowering the transmission jack, move the rear differential forward, and remove the rear differential from the vehicle.
19. Remove the rear differential member plate from the rear differential.

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1. Attach the rear differential member plate to the rear differential.
2. Set the rear differential to transmission jack.
3. Adjust the transmission jack and properly insert the rear differential stud bolt into rear crossmember bushing.
4. After inserting the rear differential stud bolt into the rear crossmember bushing, lift up the transmission jack and align the rear differential to its attachment position.
5. Install the dynamic damper assembly. (5 door AT model)
6. Tighten a new self-locking nut temporarily to rear crossmember.
7. Install the rear differential front member with a new self-locking nut. Tightening torque: T1:50 N.m (5.1 kgf-m, 36.9 ft-lb) T2:110 N.m (11.2 kgf-m, 81.1 ft-lb)
8. Tighten the self-locking nut. Tightening torque: 70 N.m (7.1 kgf-m, 51.6 ft-lb)
9. Attach the ST to rear differential. ST 28099PA090 OIL SEAL PROTECTOR
10. Insert the spline shaft until the spline portion comes inside the side oil seal.
11. Remove ST from rear differential.
12. Push the housing to fully insert the DOJ into the rear differential.
13. Lower the transmission jack.
14. Installing procedure hereafter is in the reverse order of removal.
15. After installing, fill the differential carrier with gear oil up to the bottom of the filler plug hole. Ref. to «REPLACEMENT»(ref-357279-S38327633232010031100000) .
16. Inspect the wheel alignment and adjust if necessary.

SIDE GEAR BACKLASH

Using a dial gauge, check the backlash of side gear.

Side gear backlash

0.10 - 0.20 mm (0.004 - 0.008 in)

If the side gear backlash is not within the specification, select the side gear thrust washer and adjust the side gear backlash as specified.

Scheme 183

HYPOID DRIVEN GEAR BACKLASH

Using a dial gauge, check the backlash of hypoid driven gear.

Hypoid driven gear backlash

0.10 - 0.20 mm (0.004 - 0.008 in)

If the hypoid driven gear backlash is not within the specification, adjust the side bearing preload or repair if necessary.

HYPOID DRIVEN GEAR RUNOUT ON ITS BACK SURFACE

Using a dial gauge, check the hypoid driven gear back surface runout.

Hypoid driven gear back surface runout

0.05 mm (0.002 in)

If the hypoid driven gear runout exceeds 0.05 mm (0.002 in), replace the hypoid driven gear.

TOOTH CONTACT BETWEEN HYPOID DRIVEN GEAR AND DRIVE PINION

Inspect the tooth contact between the hypoid driven gear and drive pinion. Ref. to ASSEMBLY , Rear Differential.

TOTAL PRELOAD

Using a spring scale, check the total preload.

Total preload

20.7 - 54.4 N (2.1 - 5.5 kgf, 4.7 - 12.2 lbf)

If the total preload is not within the specification, adjust the side retainer shim.

Scheme 184

Scheme 185

1. If rust or dirt is attached to the companion flange, remove them.
2. Set a dial gauge at a companion flange surface (mating surface of propeller shaft and companion flange), and then measure the companion flange runout. Limit of runout: 0.08 mm (0.003 in)
3. Set the gauge inside of the companion flange, and measure the runout. Limit of runout: 0.08 mm (0.003 in)
4. If either runout exceeds the limit, move the phase of companion flange and drive pinion 90° each, and find the point where the runout is within the limit.
5. If the runout exceeds the limit after changing the phase, replace the companion flange and recheck the runout.
6. If the runout exceeds the limit after replacing the companion flange, the drive pinion may be assembled incorrectly or bearing is faulty.

Adjust the side gear backlash. Ref. to ASSEMBLY , Rear Differential.

Adjust hypoid driven gear backlash. Ref. to ASSEMBLY , Rear Differential.

Adjust the tooth contact between hypoid driven gear and drive pinion gear. Ref. to ASSEMBLY , Rear Differential.

Adjust the side retainer shim. Ref. to ASSEMBLY , Rear Differential.