DIFFERENTIALS > Rear Differential (VA-type)

ASSEMBLY

NOTE:

• Assemble in the reverse order of disassembly.

• Check and adjust each part during assembly.

• Use new gaskets and O-rings.

• Keep the shims and washers in order, so that they are not improperly installed.

• Thoroughly clean the surfaces on which the shims, washers and bearings are to be installed.

• Apply gear oil when installing the bearings and thrust washers.

• Be careful not to mix up the RH and LH bearing races.

• Replace the oil seal and O-ring with a new part at every disassembly.

• Apply differential gear oil to the lips when installing the oil seal.

• Be careful not to mix up the differential oil seal RH and LH.

1. Adjusting preload for front and rear bearings

NOTE:

Adjust the bearing preload between front and rear bearings with spacer and washer. Pinion height adjusting washer is not affected by this adjustment. The adjustment must not be carried out with oil seal inserted.

(1) Install the rear bearing race into the differential carrier using ST1 and ST2.

ST1    398477701 HANDLE
ST2    398477702 DRIFT

(2) Install the front bearing race to the differential carrier using ST1 and ST2.

ST1    398477701 HANDLE
ST2    498447110 DRIFT

(3) Insert the front bearing cone.

NOTE:

Use new front bearing cone.

(4) Measure and record the thickness of the pinion height adjusting washer.

NOTE:

If tooth contact (drive pinion and hypoid driven gear) is normal in the inspection before disassembling, verify that the washer is not deformed, and then reuse the used washer.

(5) Insert ST1 into the case with the pinion height adjusting washer and rear bearing cone fitted onto it.

NOTE:

Use new rear bearing cone.

(6) Install the preload adjusting spacer & washer, front bearing cone, spacer, companion flange, and washer & self-locking nut.

ST    498447150 DUMMY SHAFT
Part No.    32285AA000 SPACER

(A)

Pinion height adjusting washer

(B)

Preload adjusting spacer

(C)

Preload adjusting washer

(D)

Spacer (SUBARU genuine parts)

(7) Turn the ST by hand to slowly seat the bearing, and tighten the self-locking nut while measuring the initial load or initial torque with a spring scale or torque wrench. Select the preload adjusting washer and spacer so that the specified preload is obtained when nut is tightened to the specified torque.

NOTE:

• Use a new self-locking nut.

• Measure the preload in direction of tangent to the flange.

• Be careful not to give excessive preload.

• When tightening the self-locking nut, lock ST1 with ST2 as shown in the figure.

ST1    498447150 DUMMY SHAFT
ST2    398507704 BLOCK

Tightening torque:

191 N·m (19.5 kgf-m, 140.9 ft-lb)

Initial load:

12.7 — 32.2 N (1.3 — 3.3 kgf, 2.9 — 7.2 lbf)

Initial torque:

0.48 — 1.22 N·m (0.05 — 0.12 kgf-m, 0.35 — 0.90 ft-lb)

Preload adjusting washer

Part No.

Thickness mm (in)

38336AA000

1.500 (0.0591)

38336AA120

1.513 (0.0596)

38336AA010

1.525 (0.0600)

38336AA130

1.538 (0.0606)

38336AA020

1.550 (0.0610)

38336AA140

1.563 (0.0615)

38336AA030

1.575 (0.0620)

38336AA150

1.588 (0.0625)

38336AA040

1.600 (0.0630)

38336AA160

1.613 (0.0635)

38336AA050

1.625 (0.0640)

38336AA170

1.638 (0.0645)

38336AA060

1.650 (0.0650)

38336AA180

1.663 (0.0655)

38336AA070

1.675 (0.0659)

38336AA190

1.688 (0.0665)

38336AA080

1.700 (0.0669)

38336AA200

1.713 (0.0674)

38336AA090

1.725 (0.0679)

38336AA210

1.738 (0.0684)

38336AA100

1.750 (0.0689)

38336AA220

1.763 (0.0694)

38336AA110

1.775 (0.0699)

Preload adjusting spacer

Part No.

Length mm (in)

32288AA040

52.3 (2.059)

32288AA050

52.5 (2.067)

31454AA100

52.6 (2.071)

32288AA060

52.7 (2.075)

31454AA110

52.8 (2.079)

32288AA070

52.9 (2.083)

31454AA120

53.0 (2.087)

32288AA080

53.1 (2.091)

32288AA090

53.3 (2.098)

2. Adjusting drive pinion height:

Adjust the drive pinion height with washer installed between the rear bearing cone and the back of pinion gear.

(1) Attach the ST2.

NOTE:

At this time, install a provisionally selected or previously used pinion height adjusting washer.

ST1    498447150 DUMMY SHAFT
ST2    498505501 DIFFERENTIAL CARRIER GAUGE
Part No.    32285AA000 SPACER

(A)

Pinion height adjusting washer

(B)

Spacer (SUBARU genuine parts)

(2) Measure the clearance “N” between the end of ST2 and the end surface of ST1 by using a thickness gauge.

NOTE:

Make sure there is no clearance between the case and ST2.

ST1    498447150 DUMMY SHAFT
ST2    498505501 DIFFERENTIAL CARRIER GAUGE

(3) Obtain the thickness of pinion height adjusting washer to be inserted from the following formula, and replace the temporarily installed washer with this one.

NOTE:

Adjust it using the 1 — 3 washers.

T = To + N − 0.05 mm (0.0020 in)

T

Thickness of pinion height adjusting washer mm (in)

                

To

Thickness of washer temporarily inserted mm (in)

                

N

Clearance of thickness gauge mm (in)

                

Memo:

(Example of calculation)

To = 0.15 mm (0.0059 in)

N = 0.1 mm (0.0039 in)

T = 0.15 mm (0.0059 in) + 0.1 mm (0.0039 in) − 0.05 mm (0.0020 in) = 0.2 mm (0.0079 in)

Result: Thickness = 0.2 mm (0.0079 in)

Therefore use part number 32295AA220.

Pinion height adjusting washer

Part No.

Thickness mm (in)

32295AA200

0.150 (0.0059)

32295AA210

0.175 (0.0069)

32295AA220

0.200 (0.0079)

32295AA230

0.225 (0.0089)

32295AA240

0.250 (0.0098)

32295AA250

0.275 (0.0108)

3. Install the selected pinion height adjusting washer on drive pinion, and press the rear bearing cone into position with ST.

ST    498175500 INSTALLER

4. Insert the drive pinion into the differential carrier, and install the preselected preload adjusting spacer and washer.

(A)

Drive pinion

(B)

Preload adjusting spacer

(C)

Preload adjusting washer

(D)

Differential carrier

5. Press-fit the front bearing cone into the carrier with ST1, ST2 and the spacer.

ST1    399780104 WEIGHT
ST2    899580100 INSTALLER
Part No.    32285AA000 SPACER

(A)

Spacer (SUBARU genuine parts)

6. Insert the spacer, then press-fit the pilot bearing with ST1 and ST2.

ST1    399780104 WEIGHT
ST2    899580100 INSTALLER

7. Fit a new oil seal with ST.

NOTE:

• Press-fit until the oil seal end comes 1 mm (0.04 in) inward from end of carrier.

• Apply differential gear oil to the oil seal lips.

ST    498447120 INSTALLER

8. Press-fit the companion flange with ST1 and ST2.

NOTE:

Be careful not to damage the bearing.

ST1    899874100 INSTALLER
ST2    399780104 WEIGHT

9. Attach the self-locking nut and use the ST to fix the companion flange in place, then tighten the self-locking nut.

NOTE:

• Use a new self-locking nut.

• Before installing the self-locking nut, apply seal material to self-locking nut threads.

Seal material:

THREE BOND 1324 (Part No. 004403042)

Tightening torque:

191 N·m (19.5 kgf-m, 140.9 ft-lb)

ST    498427200 FLANGE WRENCH

10. Check the initial torque or initial load.

Initial load:

12.7 — 32.2 N (1.3 — 3.3 kgf, 2.9 — 7.2 lbf)

Initial torque:

0.48 — 1.22 N·m (0.05 — 0.12 kgf-m, 0.35 — 0.90 ft-lb)

11. Assembling differential case

Install the side gears and pinion mate gears, with their thrust washers and pinion mate shaft, into the differential case.

NOTE:

• Apply gear oil on both sides of the washer and on the side gear shaft before installing.

• Install the pinion mate shaft to the differential case by aligning the spring pin holes.

• The thrust washer inner surface has a chamfered side. Install the washer with the chamfered side facing toward the side gear.

(1) Measure the side gear backlash.

Side gear backlash:

0.05 — 0.15 mm (0.002 — 0.006 in)

(2) Adjust the side gear backlash by selecting side gear thrust washer.

Side gear thrust washer

Part No.

Thickness mm (in)

803135011

0.925 — 0.950 (0.0364 — 0.0374)

803135012

0.950 — 0.975 (0.0374 — 0.0384)

803135013

0.975 — 1.000 (0.0384 — 0.0394)

803135014

1.000 — 1.025 (0.0394 — 0.0404)

803135015

1.025 — 1.050 (0.0404 — 0.0413)

(3) Check the condition of rotation after applying oil to the gear tooth surfaces and thrust washer surfaces.

(4) Attach the spring pin to the differential case.

NOTE:

Use new spring pin.

12. Install the hypoid driven gear to differential case.

NOTE:

• Before installing bolts, apply seal material to bolt threads.

Seal material:

THREE BOND 1324 (Part No. 004403042) or equivalent

• Tighten opposing bolts in order.

Tightening torque:

62 N·m (6.3 kgf-m, 45.7 ft-lb)

13. Using the ST, press-fit the side bearing to the differential case.

ST    498485400 DRIFT

14. Assemble the side retainer.

(1) Install the oil seal into side retainer RH and LH.

ST    498447100 INSTALLER

(2) Install the bearing race into side retainer RH and LH.

CAUTION:

Make sure that the RH and LH oil seals, bearing outer races and cones are properly assembled.

ST    398477702 DRIFT

(3) Install the differential case assembly into differential carrier in the reverse order of disassembly.

NOTE:

Be careful not to hit the teeth of hypoid driven gear against the differential carrier.

(4) Temporally tighten the side retainers RH and LH in differential carrier to install.

15. Perform the backlash adjustment between the hypoid driven gear and drive pinion, and preload adjustment of differential side bearing.

(1) Turn the drive pinion with ST for better fitting of differential side bearing.

ST    498427200 FLANGE WRENCH

(2) Using the ST, tighten side retainer RH, and then tighten side retainer LH until there is no backlash.

ST    18630AA010 WRENCH COMPL RETAINER

(3) Loosen the side retainer LH by approx. 1 and 1/2 teeth, and tighten the side retainer RH by approx. 2 teeth [amount that the side retainer LH is turned back (1 and 1/2) + approx. 0.5 teeth].

Difference between [amount that the side retainer LH is turned back (approx. 1 and 1/2 teeth)] and [amount that the side retainer RH is tightened (approx. 2 teeth)] gives preload.

(4) Temporarily tighten the lock plate.

NOTE:

Turn over the lock plate to shift the holder by 1/2 tooth.

(5) Measure the hypoid driven gear-to-drive pinion backlash. Set the magnet base on differential carrier. Align the contact point of dial gauge with tooth face of hypoid driven gear, and move hypoid driven gear while holding drive pinion still. Read the value indicated on dial gauge.

NOTE:

If measured value of backlash is not within the specified range, repeat the procedures for pinion driven gear set backlash adjustment and the differential side bearing preload adjustment.

Backlash:

0.10 — 0.15 mm (0.004 — 0.006 in)

16. Put alignment marks on both the differential carrier and side retainer. Install O-rings to the side retainers one by one and restore the side retainers to the original positions.

(A)

Alignment mark

(B)

Side retainer

17. Install the lock plate.

Tightening torque:

25 N·m (2.5 kgf-m, 18.4 ft-lb)

18. Recheck the hypoid driven gear to pinion backlash.

Backlash:

0.10 — 0.15 mm (0.004 — 0.006 in)

19. Checking and adjusting the tooth contact of hypoid driven gear

(1) Apply lead-free red dye evenly on the both sides of three to four teeth of the hypoid driven gear. Check the contact pattern after rotating the hypoid driven gear several revolutions back and forth until a definite contact pattern appears on the hypoid driven gear.

(2) When the contact pattern is not correct, readjust.

NOTE:

Be sure to wipe off the lead-free red dye completely after the adjustment is completed.

• Correct tooth contact

Check item: Tooth contact pattern is slightly shifted toward toe side under no-load rotation. (When driving, it moves towards the heel side.)

(A)

Toe side

(B)

Heel side

• Face contact

Check item: Backlash is too large.

Contact pattern

Corrective action: Increase thickness of pinion height adjusting washer according to the procedure for bringing drive pinion close to hypoid driven gear side.

• Flank contact

Check item: Backlash is too small.

Contact pattern

Corrective action: Reduce the thickness of pinion height adjusting washer according to the procedure for bringing drive pinion away from hypoid driven gear.

• Toe contact (inside contact)

Check item: Teeth contact area is too small.

Contact pattern

Corrective action: Reduce the thickness of pinion height adjusting washer according to the procedure for bringing drive pinion away from hypoid driven gear.

• Heel contact (outside end contact)

Check item: Teeth contact area is too small.

Contact pattern

Corrective action: Increase thickness of pinion height adjusting washer according to the procedure for bringing drive pinion close to hypoid driven gear side.

20. If correct tooth contact is not obtained, readjust the drive pinion height and the differential side bearing preload (already mentioned) and the hypoid gear backlash.

21. Install the gasket and the rear cover to the differential carrier.

NOTE:

Use a new gasket.

Tightening torque:

25 N·m (2.5 kgf-m, 18.4 ft-lb)

(A)

Rear cover

22. Install the air breather cap.

NOTE:

Do not tap section (A) of the air breather cap. Be sure to tap section (B) to install.

23. Install the oil drain plug.

NOTE:

Use a new gasket.

Tightening torque:

50 N·m (5.1 kgf-m, 36.9 ft-lb)

24. Install the oil filler plug.

NOTE:

After installing the rear differential assembly to the vehicle, fill the gear oil, then use a new gasket, and tighten to the specified torque.