Subaru Outback (BR): Front Differential Assembly in Manual Transmission

A: REMOVAL

1) Remove the manual transmission assembly from the vehicle. <Ref. to 6MT-25, REMOVAL, Manual Transmission Assembly.>

2) Remove the transfer case together with the extension case assembly. <Ref. to 6MT-40, REMOVAL, Transfer Case and Extension Case Assembly.>

3) Remove the transmission case. <Ref. to 6MT- 57, REMOVAL, Transmission Case.>

4) Remove the drive pinion shaft assembly. <Ref. to 6MT-67, REMOVAL, Drive Pinion Shaft Assembly.>

5) Remove the main shaft assembly for single-range.

<Ref. to 6MT-60, REMOVAL, Main Shaft Assembly for Single-Range.>

6) Remove the front differential assembly.

NOTE:

• Do not confuse the right and left roller bearing outer races.
• Be careful not to damage the oil seal of retainer.

7) Remove the differential side retainers using ST.

ST 18658AA020 WRENCH COMPL RETAINER

8) Remove the bearing outer race from the transmission case.

ST 398527700 PULLER ASSY

B: INSTALLATION

1) Install the differential side retainers using ST.

ST 18658AA020 WRENCH COMPL RETAINER 2) Install the bearing outer race to the transmission case.

3) Install the front differential assembly.

NOTE: Be careful not to fold the sealing lip of oil seal.

4) Install the main shaft assembly for single-range.

<Ref. to 6MT-60, INSTALLATION, Main Shaft Assembly for Single-Range.>

5) Install the drive pinion shaft assembly. <Ref. to 6MT-67, INSTALLATION, Drive Pinion Shaft Assembly.>

6) Install the transmission case. <Ref. to 6MT-58, INSTALLATION, Transmission Case.>

7) Install the transfer case together with the extension case assembly. <Ref. to 6MT-40, INSTALLATION, Transfer Case and Extension Case Assembly.>

8) Install the manual transmission assembly to the vehicle. <Ref. to 6MT-29, INSTALLATION, Manual Transmission Assembly.>

C: DISASSEMBLY

1. DIFFERENTIAL CASE ASSY

1) Loosen the twelve bolts and remove hypoid driven gear.

1. Hypoid driven gear

2) Drive out the straight pin from differential assembly toward hypoid driven gear side.

ST 899904100 STRAIGHT PIN REMOVER

3) Pull out the pinion shaft, and remove the differential bevel pinion, differential bevel gear and washer.

1. Pinion shaft
2. Differential bevel pinion
3. Differential bevel gear
4. Washer

4) Using the ST, remove the roller bearing.

ST 899524100 PULLER SET

2. SIDE RETAINER

1) Remove the O-ring.

2) Remove the oil seal.

NOTE:

• Remove it by using flat tip screwdriver.
• Do not reuse the oil seal. Replace the oil seal with a new part.

D: ASSEMBLY

1. DIFFERENTIAL CASE ASSY

1) Install the differential bevel gear and differential bevel pinion together with washer, and insert the pinion shaft.

NOTE: Face the chamfered side of washer toward gear.

1. Differential bevel pinion
2. Differential bevel gear
3. Pinion shaft

2) Measure the backlash between the differential bevel gear and differential bevel pinion. If backlash is out of specifications, install a suitable washer to adjust. <Ref. to 6MT-81, BEVEL PINION GEAR BACKLASH, INSPECTION, Front Differential Assembly.>

NOTE: Be sure the pinion gear teeth contacts adjacent gear teeth during measurement.

Standard backlash 0.13 - 0.18 mm (0.0051 - 0.0071 in)

ST1 498247001 MAGNET BASE
ST2 498247100 DIAL GAUGE

3) Align the pinion shaft and differential case with each hole, and drive the straight pin into the holes from the hypoid driven gear side using the ST.

NOTE: Use a new straight pin.

ST 899904100 STRAIGHT PIN REMOVER

1. Pinion shaft
2. Differential case
3. Straight pin

4) Install the roller bearing to differential case.

CAUTION: Do not apply a load in excess of 10 kN (1 ton, 1.1 US ton, 1.0 Imp ton).

NOTE: Be careful because the roller bearing outer races are used as a set.

ST1 499277100 BUSHING 1-2 INSTALLER
ST2 398497701 ADAPTER

5) Install the hypoid driven gear to the differential case using twelve bolts.

Tightening torque: T: 62 N*m (6.3 kgf-m, 45.7 ft-lb)

1. Hypoid driven gear
2. Differential case

2. SIDE RETAINER

1) Using the ST, install the oil seal by lightly tapping with a plastic hammer.

NOTE:

• Use a new oil seal.
• Apply transmission gear oil to the oil seal lips, and install the oil seal while being careful not to deform the lip.
• Check the identification marks (L, R), attach the oil seal RH and LH.

ST 18675AA000 DIFFERENTIAL SIDE OIL SEAL INSTALLER

2) Install the O-ring.

NOTE:

• Use new O-rings.
• Apply gear oil to O-ring.
• Do not stretch or damage the O-ring.

E: INSPECTION

Repair or replace the differential gear in the following cases:

• When the hypoid drive gear and drive pinion shaft tooth surfaces are damaged, excessively worn, or seized.
• When the roller bearing on the drive pinion shaft has a worn or damaged roller path.
• When there is damage, wear or seizure of the differential bevel pinion, differential bevel gear, washer, pinion shaft or straight pin.
• When the differential case sliding surfaces are worn or damaged.

1. Drive pinion shaft
2. Hypoid driven gear
3. Pinion shaft
4. Straight pin
5. Washer
6. Differential bevel gear
7. Differential bevel pinion
8. Roller bearing
9. Differential case

1. BEVEL PINION GEAR BACKLASH

Measure the backlash between the differential bevel gear and differential bevel pinion. If backlash is out of specifications, install a suitable washer to adjust.

<Ref. to 6MT-82, ADJUSTMENT, Front Differential Assembly.>

Standard backlash 0.13 - 0.18 mm (0.0051 - 0.0071 in)

ST1 498247001 MAGNET BASE
ST2 498247100 DIAL GAUGE

2. HYPOID GEAR BACKLASH

1) Set the ST1, ST2 and ST3. Insert the needle through drain plug hole so that the needle comes in contact with the tooth surface on the right corner, and check the backlash.

ST1 498247001 MAGNET BASE
ST2 498247100 DIAL GAUGE
ST3 498255400 PLATE

2) Secure the drive pinion shaft using the ST, install SUBARU genuine axle shafts to both sides, rotate in the both directions so that the gauge contacts the tooth surface, and read the dial gauge.

NOTE: If the backlash is outside the specified range, adjust it by turning the side retainer in the right side case.

Backlash 0.13 - 0.18 mm (0.0051 - 0.0071 in)

ST 18667AA020 HOLDER
Part No. 38415AA100 Axle shaft

3. TOOTH CONTACT OF HYPOID GEAR

Check tooth contact of hypoid gear as follows: Apply a thin uniform coat of red lead on both teeth surfaces on 3 or 4 teeth of the hypoid gear. Move the hypoid gear back and forth by turning the transmission main shaft until a definite contact pattern is developed on the hypoid gear, and judge whether face contact is correct. When the contact pattern is not correct, adjust. <Ref. to 6MT-82, ADJUSTMENT, Front Differential Assembly.>

• Tooth contact is correct.

1. Toe
2. Coast side
3. Heel
4. Drive side

F: ADJUSTMENT

1. BEVEL PINION GEAR BACKLASH

1) Disassemble the front differential assembly.

<Ref. to 6MT-78, DISASSEMBLY, Front Differential Assembly.>

2) Select a suitable washer for the differential bevel gear from the table and install.

3) Adjust until the standard value is obtained.

Backlash:
Standard 0.13 - 0.18 mm (0.0051 - 0.0071 in)

2. HYPOID GEAR BACKLASH

Adjust the backlash by turning the side retainer in the RH side case.

ST 18658AA020 WRENCH COMPL RETAINER

NOTE: Each time the side retainer rotates by one notch (A), the backlash changes by 0.05 mm (0.0020 in).

3. TOOTH CONTACT OF HYPOID GEAR

1) Adjust until correct teeth contact is obtained.

2) Check tooth contact, and perform the adjustment as follows.

• Tooth contact

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

1. Toe side
2. Heel side

• Face contact

Check item: Backlash is too large.

Contact pattern

Corrective action: Tighten the side retainer to move the driven gear closer to the drive pinion.

• Flank contact

Check item: Backlash is too small.

Contact pattern

Corrective action: Loosen the side retainer to move the driven gear away from the drive pinion.

• Toe contact (inside contact)

Check item: Teeth contact area is too small.

Contact pattern

Corrective action: Increase thickness of the drive pinion shim according to the procedures for moving the drive pinion shaft away from the driven gear.

Also tighten the side retainer to move the driven gear closer to the drive pinion shaft.

• Heel contact (outside end contact)

Check item: Teeth contact area is too small.

Contact pattern

Corrective action: Reduce thickness of the drive pinion shim according to the procedures for moving the drive pinion shaft closer to driven gear. Also loosen the side retainer to move the driven gear away from the drive pinion.

READ NEXT: