Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual - part 502

DI-53

Rear Differential (T-type)

DIFFERENTIALS

5. TOTAL PRELOAD

Using a spring scale, check the total preload.
Total preload:

T-type (B2):

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

T-type (H3):

26.5 — 53 N (2.7 — 5.4 kgf, 6.0 — 11.9 lbf)

If  the  total  preload  is  not  within  the  specification,

adjust the side retainer shim.

6. COMPANION FLANGE

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 assem-

bled incorrectly or bearing is faulty.

F: ADJUSTMENT

1. SIDE GEAR BACKLASH (T-TYPE (B2))

Adjust the side gear backlash. <Ref. to DI-31, AS-

SEMBLY, Rear Differential (T-type).>

2. HYPOID DRIVEN GEAR BACKLASH

Adjust hypoid driven gear backlash. <Ref. to DI-31,

ASSEMBLY, Rear Differential (T-type).>

3. TOOTH CONTACT BETWEEN HYPOID 

DRIVEN GEAR AND DRIVE PINION

Adjust  the  tooth  contact  between  hypoid  driven

gear and drive pinion gear. <Ref. to DI-31, ASSEM-

BLY, Rear Differential (T-type).>

4. TOTAL PRELOAD

Adjust the side retainer shim. <Ref. to DI-31, AS-

SEMBLY, Rear Differential (T-type).>

DI-00117

DI-00360

DI-00361

DI-54

Rear Differential Front Oil Seal

DIFFERENTIALS

5. Rear Differential Front Oil 

Seal

A: INSPECTION

Check that there is no leakage from front oil seal

portion. If there is any leakage replace the oil seal

and inspect the propeller shaft.

B: REPLACEMENT

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) Disconnect  the  oil  temperature  switch  connec-

tor. (T-type (H3))

6) Remove the drain plug and filler plug or the oil

temperature switch, and drain the gear oil.
NOTE:

Remove the oil temperature switch and adapter as

a unit.

• T-type (B2)

• T-type (H3)

7) Install the drain plug.
NOTE:

• For  the  T-type  (B2),  apply  liquid  gasket  to  the

drain plug.

• For T-type (H3), use a new gasket.
Liquid gasket:

THREE BOND 1105 (Part No. 004403010) or 

equivalent

Tightening torque:

T-type (B2);

49 N·m (5.0 kgf-m, 36.1 ft-lb)

T-type (H3);

60 N·m (6.1 kgf-m, 44.3 ft-lb)

8) Remove the rear exhaust pipe and muffler.

• 6MT model

<Ref.  to  EX(STI)-13,  REMOVAL,  Rear  Exhaust

Pipe.> <Ref. to EX(STI)-15, REMOVAL, Muffler.>

• 5MT model

<Ref. to EX(w/o STI)-2, General Description.>

9) Remove the heat shield cover.

10) Remove  the  propeller  shaft.  <Ref.  to  DS-11,

REMOVAL, Propeller Shaft.>

11) Check the initial torque and write it down.

(A) Oil temperature switch connector

(A) Filler plug
(B) Drain plug

DI-00749

(A)

DI-00522

(A)

(B)

(A) Oil temperature switch
(B) Drain plug

DI-00593

(A)

(B)

AT-04522

DI-55

Rear Differential Front Oil Seal

DIFFERENTIALS

12) Remove the self-locking nut while holding the

companion flange with ST.

ST 18633AA000 WRENCH COMPL (T-TYPE 

(H3))

ST 498427200

FLANGE WRENCH (T-TYPE 

(B2))

13) Remove the companion flange using ST.

ST 399703600

PULLER ASSY

14) Remove the oil seal using ST or screwdriver.

ST 398527700

PULLER ASSY

15) 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

16) Use  a  plastic  hammer  to  install  companion

flange.

17) Tighten  the  self-locking  nut  to  the  specified

torque so that the rotating resistance of the com-

panion flange is the same value as that before re-

placing the oil seal.
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) or 

equivalent

Tightening torque:

167 — 196 N·m (17.0 — 20.0 kgf-m, 123.2 — 

144.6 ft-lb)

ST 18633AA000 WRENCH COMPL (T-TYPE 

(H3))

ST 498427200

FLANGE WRENCH (T-TYPE 

(B2))

18) Hereafter, reassemble in the reverse order of

disassembly.

19) After  installing,  fill  the  differential  carrier  with

gear oil up to the bottom of the filler plug hole or the

oil  temperature  switch  hole.  <Ref.  to  DI-19,  RE-

PLACEMENT, Differential Gear Oil.>

DI-00194

ST

DI-00196

ST

DI-00197

ST

DI-00292

ST

ST

DI-00199

DI-56

Rear Differential Side Oil Seal

DIFFERENTIALS

6. Rear Differential Side Oil Seal

A: INSPECTION

Check that there is no oil leakage from the side oil

seal. If there is any leakage, replace the oil seal.

B: REPLACEMENT

1) Remove the rear differential. <Ref. to DI-22, RE-

MOVAL, Rear Differential (T-type).>

2) Remove the rear differential side oil seal using a

ST or screwdriver wrapped with vinyl tape to pre-

vent the side retainer from scratching.

ST 398527700

PULLER ASSY

3) Using the ST, install the side oil seal.
NOTE:

• Use a new oil seal.

• Apply differential gear oil to the oil seal lips.

ST 398437700

DRIFT

4) Install  the  rear  differential.  <Ref.  to  DI-24,  IN-

STALLATION, Rear Differential (T-type).>

ST

DI-00208

DI-00209

ST