Subaru Legacy IV (2008 year). Manual - part 794

5MT-72

Front Differential Assembly

MANUAL TRANSMISSION AND DIFFERENTIAL

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

NOTE:
Lock the straight pin after installing.
ST

899904100

REMOVER

4) Install the roller bearing to differential case.

CAUTION:
Do not apply pressure 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)

2. SIDE RETAINER

1) Install a new oil seal.
ST

18675AA000

DIFFERENTIAL SIDE OIL 
SEAL INSTALLER

CAUTION:
• When press-fitting the oil seal to the side re-
tainer, tap with a plastic hammer etc. to press
in.
• Do not use a press.
2) Install a new O-ring.

NOTE:
Do not stretch or damage the O-ring.

(A) Pinion shaft

(B) Differential case

(C) Straight pin

MT-00286

(A)

(C)

(B)

MT-00287

ST1

ST2

(A) Hypoid driven gear

(B) Differential case

MT-00993

(B)

(A)

T

MT-00289

ST

MT-00279

5MT-73

Front Differential Assembly

MANUAL TRANSMISSION AND DIFFERENTIAL

E: INSPECTION

Repair or replace the differential gear in the follow-
ing 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 dif-
ferential bevel pinion, differential bevel gear, wash-
er, pinion shaft or straight pin.
• When the differential case has worn or damaged
sliding surfaces.

1. BEVEL PINION GEAR BACKLASH

Measure the backlash between the differential bev-
el gear and differential bevel pinion. If backlash is
not within specified value, install a suitable washer
to adjust. <Ref. to 5MT-74, ADJUSTMENT, Front
Differential Assembly.>
ST1

498247001

MAGNET BASE

ST2

498247100

DIAL GAUGE

Standard backlash

0.13 — 0.18 mm (0.0051 — 0.0071 in)

2. HYPOID GEAR BACKLASH

1) Set the ST1, ST2 and ST3. Insert the needle
through transmission oil 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) Install SUBARU genuine axle shafts to both
sides, rotate in the inversion direction so that the
gauge contacts the tooth surface, and read the dial
gauge
Part No. 38415AA100

Axle shaft

Backlash

0.13 — 0.18 mm (0.0051 — 0.0071 in)

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

(A) Drive pinion shaft

(B) Hypoid driven gear

(C) Pinion shaft

(D) Straight pin

(E) Washer

(F) Differential bevel gear

(G) Differential bevel pinion

(H) Roller bearing

(I) Differential case

(I)

(H)

(D)

(C)

(B)

(E)

(F)

(G)

(F)

(E)

(A)

(H)

(G)

MT-01074

MT-00285

ST1

ST2

MT-00293

ST1

ST2

ST3

5MT-74

Front Differential Assembly

MANUAL TRANSMISSION AND DIFFERENTIAL

3. TOOTH CONTACT OF HYPOID GEAR

Check tooth contact of hypoid gear as follows: Ap-
ply a thin uniform coat of red lead on both teeth sur-
faces on 3 or 4 teeth of the hypoid gear. Move the
hypoid gear back and forth by turning the transmis-
sion main shaft until a definite contact pattern is de-
veloped on the hypoid gear, and judge whether
face contact is correct. When the contact pattern is
not correct, adjust the tooth contact. <Ref. to 5MT-
74, ADJUSTMENT, Front Differential Assembly.>
• Tooth contact is correct.

F: ADJUSTMENT

1. BEVEL PINION GEAR BACKLASH

1) Disassemble the front differential assembly.
<Ref. to 5MT-70, DISASSEMBLY, Front Differen-
tial Assembly.>
2) Select a different washer from the table and in-
stall.

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

18630AA010

WRENCH COMPL RETAINER

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

(A) Toe

(B) Coast side

(C) Heel

(D) Drive side

MT-01402

(B)

(D)

(C)

(A)

Washer

Part number

Thickness mm (in)

803038021

0.925 — 0.950

(0.0364 — 0.0374)

803038022

0.975 — 1.000

(0.0384 — 0.0394)

803038023

1.025 — 1.050

(0.0404 — 0.0413)

MT-00176

ST

MT-00296

0.05mm(0.0020 in)

5MT-75

Front Differential Assembly

MANUAL TRANSMISSION AND DIFFERENTIAL

3. TOOTH CONTACT OF HYPOID GEAR

1) Adjust until correct teeth contact is obtained.
2) Check tooth contact, and perform the adjust-
ment as follows.
• Tooth contact
Check item: Tooth contact surface is slightly
shifted toward the toe side under a no-load con-
dition. (When driving, it moves towards the 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 closer to the driven gear.

(A) Toe side

(B) Heel side

(A)

(B)

MT-01401

AT-00208

MT-01799

AT-00209

MT-01800

AT-00210

AT-00213