Subaru Impreza 2.5 L 2004 User manual

DIFFERENTIALS

DI-2
DIFFERENTIALS
GENERAL DESCRIPTION
1. General Description
A: SPECIFICATIONS
When replacing a rear differential assembly, select the correct one according to the following table.
NOTE:
Using the different rear differential assembly causes the drive line and tires to “drag”or emit abnormal noise
when AWD is selected.
•Identification •Rear differential gear oil
Recommended oil
CAUTION:
Each oil manufacturer has its base oil and addi-
tives. Thus, do not mix two or more brands.
MODEL
2.5 L 2.0 L Turbo
AT MT AT MT
Wagon Sedan Wagon Sedan
Rear differential type T-type model without LSD T-type model with LSD
LSD type —Viscous coupling
Identification EH EL EG EH EJ EF
Type of gear Hypoid gear
Gear ratio (Number of gear
teeth) 4.111 (37/9) 4.444 (37/9) 3.900 (39/10) 4.111 (37/9) 3.545 (39/11)
Oil capacity 0.8 2(0.8 US qt, 0.7 Imp qt)
Rear differential gear oil GL-5
MODEL 2.5 L Turbo STi
6MT
Rear differential type T-type model with LSD
LSD type Mechanical
Identification HK
Type of gear Hypoid gear
Gear ratio (Number of gear
teeth) 3.900 (39/10)
Oil capacity 0.9 —1.1 2(1.0 —1.2 US qt,
0.8 —1.0 Imp qt)
Rear differential gear oil GL-5 (For mechanical LSD)
DI-00001
(1) Item
(2) Differential gear oil
(3) API Classification
(4) SAE Viscosity NO. and Application Temperature
MT-00001
(1)
(4)
GL-5
(3)
(2)
( C)
( F)
-30 -26 -15 15
90
85W
80W
75W -90
25 30-5 0
-22 -15 23 32 8659 775

DI-3
DIFFERENTIALS
GENERAL DESCRIPTION
1. SERVICE DATA
2. ADJUSTING PARTS
•Except STi model
Front and rear bearing preload at companion flange bolt
hole N (kgf, lb)
Except STi
model 18.1 —38.8 (1.8 —4.0, 4.1 —8.7)
STi model 24.1 —38.6 (2.5 —3.9, 5.4 —8.7)
Side gear backlash mm (in) 0.10 —0.20 (0.0039 —0.0079)
Side bearing standard width mm (in) 20.00 (0.7874)
Crown gear to drive pinion backlash mm (in) 0.10 —0.20 (0.0039 —0.0079)
Crown gear runout on its back surface mm (in) Less than 0.05 (0.0020)
Front and rear bearing preload at com-
panion flange bolt hole N (kgf, lb) 18.1 —38.8 (1.8 —4.0, 4.1 —8.7)
Preload adjusting spacer
Part No. Length mm (in)
383695201 56.2 (2.213)
383695202 56.4 (2.220)
383695203 56.6 (2.228)
383695204 56.8 (2.236)
383695205 57.0 (2.244)
383695206 57.2 (2.252)
Preload adjusting washer
Part No. Length mm (in)
383705200 2.59 (0.1020)
383715200 2.57 (0.1012)
383725200 2.55 (0.1004)
383735200 2.53 (0.0996)
383745200 2.51 (0.0988)
383755200 2.49 (0.0980)
383765200 2.47 (0.0972)
383775200 2.45 (0.0965)
383785200 2.43 (0.0957)
383795200 2.41 (0.0949)
383805200 2.39 (0.0941)
383815200 2.37 (0.0933)
383825200 2.35 (0.0925)
383835200 2.33 (0.0917)
383845200 2.31 (0.0909)

DI-4
DIFFERENTIALS
GENERAL DESCRIPTION
•STi model
Pinion height adjusting shim
Part No. Thickness mm (in)
383495200 3.09 (0.1217)
383505200 3.12 (0.1228)
383515200 3.15 (0.1240)
383525200 3.18 (0.1252)
383535200 3.21 (0.1264)
383545200 3.24 (0.1276)
383555200 3.27 (0.1287)
383565200 3.30 (0.1299)
383575200 3.33 (0.1311)
383585200 3.36 (0.1323)
383595200 3.39 (0.1335)
383605200 3.42 (0.1346)
383615200 3.45 (0.1358)
383625200 3.48 (0.1370)
383635200 3.51 (0.1382)
383645200 3.54 (0.1394)
383655200 3.57 (0.1406)
383665200 3.60 (0.1417)
383675200 3.63 (0.1429)
383685200 3.66 (0.1441)
Side gear backlash mm (in) 0.1 —0.2 (0.0039 —0.0079)
Side gear thrust washer
(Model without LSD)
Part No. Thickness mm (in)
383445201 0.75 —0.80 (0.0295 —0.0315)
383445202 0.80 —0.85 (0.0315 —0.0335)
383445203 0.85 —0.90 (0.0335 —0.0354)
Side bearing standard width mm (in) —20.00 (0.7874)
Side bearing retainer shim
Part No. Thickness mm (in)
383475201 0.20 (0.0079)
383475202 0.25 (0.0098)
383475203 0.30 (0.0118)
383475204 0.40 (0.0157)
383475205 0.50 (0.0197)
Crown gear to drive pinion
backlash mm (in) Limit
0.10 —0.20 (0.0039 —0.0079)
Crown gear runout on its back
surface mm (in) 0.05 (0.0020)
Front and rear bearing preload at com-
panion flange bolt hole N (kgf, lb) 24.1 —38.6 (2.5 —3.9, 5.4 —8.7)
Preload adjusting spacer
Part No. Length mm (in)
31454AA130 52.2 (2.055)
31454AA140 52.4 (2.063)
31454AA150 52.6 (2.071)
31454AA160 52.8 (2.079)
31454AA170 53.0 (2.087)
31454AA180 53.2 (2.094)

DI-5
DIFFERENTIALS
GENERAL DESCRIPTION
Preload adjusting washer
Part No. Length mm (in)
383705200 2.59 (0.1020)
383715200 2.57 (0.1012)
383725200 2.55 (0.1004)
383735200 2.53 (0.0996)
383745200 2.51 (0.0988)
383755200 2.49 (0.0980)
383765200 2.47 (0.0972)
383775200 2.45 (0.0965)
383785200 2.43 (0.0957)
383795200 2.41 (0.0949)
383805200 2.39 (0.0941)
383815200 2.37 (0.0933)
383825200 2.35 (0.0925)
383835200 2.33 (0.0917)
383845200 2.31 (0.0909)
Pinion height adjusting shim
Part No. Length mm (in)
38336AA230 3.09 (0.1217)
38336AA240 3.12 (0.1228)
38336AA250 3.15 (0.1240)
38336AA260 3.18 (0.1252)
38336AA270 3.21 (0.1264)
38336AA280 3.24 (0.1276)
38336AA290 3.27 (0.1287)
38336AA300 3.30 (0.1299)
38336AA310 3.33 (0.1311)
38336AA320 3.36 (0.1323)
38336AA330 3.39 (0.1335)
38336AA340 3.42 (0.1346)
38336AA350 3.45 (0.1358)
38336AA360 3.48 (0.1370)
38336AA370 3.51 (0.1382)
38336AA380 3.54 (0.1394)
38336AA390 3.57 (0.1406)
38336AA400 3.60 (0.1417)
38336AA410 3.63 (0.1429)
38336AA420 3.66 (0.1441)
Side bearing standard width mm (in) 20.00 (0.7874)
Side bearing retainer shim
Part No. Thickness mm (in)
383475201 0.20 (0.0079)
383475202 0.25 (0.0098)
383475203 0.30 (0.0118)
383475204 0.40 (0.0157)
383475205 0.50 (0.0197)
Crown gear to drive pinion
backlash mm (in) Limit
0.10 —0.20 (0.0039 —0.0079)
Crown gear runout on its back
surface mm (in) 0.05 (0.0020)

DI-6
DIFFERENTIALS
GENERAL DESCRIPTION
B: COMPONENT
1. REAR DIFFERENTIAL WITHOUT LSD
(1) Pinion crown gear and drive pin-
ion set
(13) Side bearing (26) Stud bolt
(14) O-ring (27) Oil filler plug
(2) Pinion height adjusting shim (15) Side bearing retainer shim (28) Oil drain plug
(3) Rear bearing (16) Side bearing retainer (29) Rear cover
(4) Bearing preload adjusting spacer (17) Side oil seal (30) Differential case
(5) Bearing preload adjusting washer (18) Side gear thrust washer (31) Gasket
(6) Differential carrier (19) Side gear
(7) Front bearing (20) Pinion mate gear Tightening torque: N·m (kgf-m, ft-lb)
(8) Spacer (21) Pinion mate gear washer T1: 10.3 (1.05, 7.6)
(9) Pilot bearing (22) Pinion shaft lock pin T2: 29 (3.0, 21.7)
(10) Front oil seal (23) Circlip T3: 49 (5.0, 36.2)
(11) Companion flange (24) Pinion mate shaft T4: 105 (10.7, 77.4)
(12) Self-locking nut (25) Air breather cap T5: 181 (18.5, 134)
DI-00260
( 1 )
( 1 )
( 2 )
( 3 )
( 4 )
( 5 )
( 6 )
( 7 )
( 8 )
( 9 )
(10)
(11)
(12)
(13)
(13)
(14)
(14)
(15)
(15)
(16)
(16)
(17)
(17)
(18)
(18)
(19)
(19)
(20)
(20)
(23) (21)
(21)
(22)
(24)
(30) (23)
(25)
(26)
(27)
(28)
(29)
(31)
T1
T2
T3
T3
T4
T5
T1

DI-7
DIFFERENTIALS
GENERAL DESCRIPTION
2. REAR DIFFERENTIAL WITH LSD
(1) Pinion crown gear and drive pin-
ion set
(14) O-ring (25) Oil filler plug (Rear differential oil
temperature switch) (STi model)
(15) Side bearing retainer shim
(2) Pinion height adjusting shim (16) Side bearing retainer (26) Stay ground (STi model)
(3) Rear bearing (17) Side oil seal
(4) Bearing preload adjusting spacer (18) Gasket Tightening torque: N·m (kgf-m, ft-lb)
(5) Bearing preload adjusting washer (19) Differential case (Viscous cou-
pling type) (Except for STi model)
T1: 10.3 (1.05, 7.6)
(6) Differential carrier T2: 29 (3.0, 21.7) (Except for STi
model)
(7) Front bearing Differential case (Mechanical
type) (STi model)
(8) Collar 44 (4.5, 32.5) (STi model)
(9) Pilot bearing (20) Rear cover T3: 49 (5.0, 36.2)
(10) Front oil seal (21) Air breather cap T4: 105 (10.7, 77.4)
(11) Companion flange (22) Stud bolt T5: 181 (18.5, 134)
(12) Self-locking nut (23) Oil filler plug
(13) Side bearing (24) Oil drain plug
DI-00347
T4
T1
(18)
(14)
(5)
(4)
(1)
(19)
(6)
(13)
(16)
(3) (2)
(1)
(17)
(15)
T1
T5
(13)
(16)
(17)
(12) (11)
(10) (9)
(8)
(7)
(14) (15)
T2
T3
T3
(21)
(22)
(23)
(25)
(24)
(20)
(26)

DI-8
DIFFERENTIALS
GENERAL DESCRIPTION
3. REAR DIFFERENTIAL MOUNTING SYSTEM
(1) Differential front member (8) Differential mount bracket Tightening torque: N·m (kgf-m, ft-lb)
(2) Plate (9) Differential mount front cover T1: 20 (2.0, 14.5)
(3) Crossmember T2: 33 (3.4, 24.3)
(4) Differential rear member T3: 65 (6.6, 47.9)
(5) Differential mount lower bracket T4: 70 (7.1, 51.6)
(6) Stopper T5: 90 (9.2, 66.4)
(7) Dynamic damper T6: 100 (10.2, 73.8)
DI-00312
(1)
T5
(7)
(6)
T1
(8)
T2 T6
T5
(9) T1
T6 T2
(8)
(6)
T3
(7)
T5 (5)
(4)
T4
T4
(3)
(2)

DI-9
DIFFERENTIALS
GENERAL DESCRIPTION
C: CAUTION
•Wear working clothing, including a cap, protec-
tive goggles, and protective shoes during opera-
tion.
•Remove contamination including dirt and corro-
sion before removal, installation or disassembly.
•Keep the disassembled parts in order and pro-
tect them from dust or dirt.
•Before removal, installation or disassembly, be
sure to clarify the failure. Avoid unnecessary re-
moval, installation, disassembly, and replacement.
•Be careful not to burn your hands, because each
part on the vehicle is hot after running.
•Use SUBARU genuine gear oil, grease etc. or
the equivalent. Do not mix gear oil, grease etc. with
that of another grade or from other manufacturers.
•Be sure to tighten fasteners including bolts and
nuts to the specified torque.
•Place shop jacks or safety stands at the specified
points.
•Apply gear oil onto sliding or revolution surfaces
before installation.
•Before installing O-rings or snap rings, apply suf-
ficient amount of gear oil to avoid damage and de-
formation.
•Before securing a part on a vise, place cushion-
ing material such as wood blocks, aluminum plate,
or shop cloth between the part and the vise.
•Avoid damaging the mating face of the case.

DI-10
DIFFERENTIALS
GENERAL DESCRIPTION
D: PREPARATION TOOL
1. SPECIAL TOOLS
ILLUSTRATION TOOL NUMBER DESCRIPTION REMARKS
398477701 HANDLE Used for installing front and rear bearing cone.
398477702 DRIFT Used press-fitting the bearing cone of differential
carrier (rear).
398217700 ATTACHMENT SET Stand for rear differential carrier disassembly
and assembly.
498447120 INSTALLER Used for installing front oil seal.
ST-398477701
ST-398477702
ST-398217700
ST-498447120

DI-11
DIFFERENTIALS
GENERAL DESCRIPTION
498427200 FLANGE WRENCH •Used for stopping rotation of companion
flange when loosening and tightening self-lock
nut.
•For except STi model.
398467700 DRIFT Used for removing pinion, pilot bearing and front
bearing cone.
399780104 WEIGHT Used for installing front bearing cone, pilot bear-
ing companion flange.
899580100 INSTALLER Used for press-fitting the front bearing cone, pilot
bearing.
ILLUSTRATION TOOL NUMBER DESCRIPTION REMARKS
ST-498427200
ST-398467700
ST-399780104
ST-899580100

DI-12
DIFFERENTIALS
GENERAL DESCRIPTION
899904100 STRAIGHT PIN
REMOVER
Used for driving out differential pinion shaft lock
pin.
498247001 MAGNET BASE •Used for measuring backlash between side
gear and pinion, and hypoid gear.
•Used with DIAL GAUGE (498247100).
498247100 DIAL GAUGE •Used measuring backlash between side gear
and pinion, hypoid gear.
•Used with MAGNET BASE (498247001).
398507704 BLOCK Used for adjusting pinion height and preload.
ILLUSTRATION TOOL NUMBER DESCRIPTION REMARKS
ST-899904100
ST-498247001
ST-498247100
ST-398507704

DI-13
DIFFERENTIALS
GENERAL DESCRIPTION
398177700 INSTALLER Used for installing rear bearing cone.
398457700 ATTACHMENT Used for removing side bearing retainer.
398477703 DRIFT2 Used for press-fitting the bearing race (rear) of
differential carrier.
398437700 DRIFT Used for installing side oil seal.
ILLUSTRATION TOOL NUMBER DESCRIPTION REMARKS
ST-398177700
ST-398457700
ST-398477703
ST-398437700

DI-14
DIFFERENTIALS
GENERAL DESCRIPTION
398507702 DUMMY SHAFT Used for adjusting pinion height and preload.
398507703 DUMMY COLLAR Used for adjusting pinion height and preload.
398517700 REPLACER Used for removing rear bearing cone.
398487700 DRIFT Used for press-fitting the side bearing cone.
ILLUSTRATION TOOL NUMBER DESCRIPTION REMARKS
ST-398507702
ST-398507703
ST-398517700
ST-398487700

DI-15
DIFFERENTIALS
GENERAL DESCRIPTION
398507701 DIFFERENTIAL
CARRIER GAUGE
Used for adjusting pinion height.
398527700 PULLER ASSY •Used for removing front oil seal.
•Used for removing side bearing cup.
398227700 WEIGHT Used for installing side bearing.
28099PA090 OIL SEAL PROTEC-
TOR
•Used for installing rear drive shaft into rear dif-
ferential.
•For protecting oil seal.
ILLUSTRATION TOOL NUMBER DESCRIPTION REMARKS
ST-398507701
ST-398527700
ST-398227700
ST28099PA090

DI-16
DIFFERENTIALS
GENERAL DESCRIPTION
398237700 GAUGE Used for installing side bearing.
28099PA100 DRIVE SHAFT
REMOVER
Used for removing rear drive shaft from rear dif-
ferential.
399703600 PULLER ASSY Used for removing companion flange.
899874100 INSTALLER Used for installing companion flange.
ILLUSTRATION TOOL NUMBER DESCRIPTION REMARKS
ST-398237700
ST28099PA100
ST-399703600
ST-899874100

DI-17
DIFFERENTIALS
GENERAL DESCRIPTION
18759AA000
(Newly adopted tool)
PULLER ASSY Used for removing side bearing cone of differen-
tial.
498937110 HOLDER DRIVE
PINION
(This special tool is
used for current
automatic transmis-
sion.)
•Used for installing pilot bearing.
•For STi model.
18674AA000
(Newly adopted tool)
INSTALLER •Used for installing rear bearing cone.
•For STi model.
398417700 DRIFT
(This special tool
was prepared for the
vehicles of 92MY
and before.)
•Used for installing side bearing race.
•For STi model.
ILLUSTRATION TOOL NUMBER DESCRIPTION REMARKS
ST18759AA000ST18759AA000
ST-498937110
ST18674AA000
ST-398417700

DI-18
DIFFERENTIALS
GENERAL DESCRIPTION
2. GENERAL PURPOSE TOOLS
18633AA000
(Newly adopted tool)
WRENCH COMPL •Used for stopping rotating of companion
flange when loosening and tightening self-lock-
ing nut.
•For STi model.
TOOL NAME REMARKS
Transmission jack Used for assembly/disassembly of rear differential.
Puller Used for removal of side bearing retainer.
Thickness gauge Used for measuring clearance.
ILLUSTRATION TOOL NUMBER DESCRIPTION REMARKS
ST18633AA000

DI-19
DIFFERENTIALS
DIFFERENTIAL GEAR OIL
2. Differential Gear Oil
A: INSPECTION
1) Disconnect the oil temperature switch connec-
tor. (STi model)
2) Remove the filler plug or rear differential oil tem-
perature switch and then check the gear oil. If it is
contaminated or deteriorated, replace the gear oil.
<Ref. to DI-19, REPLACEMENT, Differential Gear
Oil.>
3) Check the gear oil level is up to the bottom part
of filler bolt. If the level is low, refill up to the bottom
of filler bolt.
B: REPLACEMENT
1) Jack-up the vehicle and support it with sturdy
racks.
2) Disconnect the oil temperature switch connec-
tor. (STi model)
3) Remove the oil drain plug and filler plug, and
drain the gear oil.
CAUTION:
Be careful not to burn your hands, because
gear oil becomes extremely hot after running.
4) Tighten the oil drain plug.
NOTE:
Apply fluid packing to the drain plug.
Fluid packing:
THREE BOND 1105 (Part No. 004403010) or
equivalent
Tightening torque:
49 N·m (5.0 kgf-m, 36.2 ft-lb)
(A) Connector
(A) Filler plug
(B) Drain plug
DI-00348
(A)
DI-00047
(B)
(A)
(A) Connector
(A) Filler plug
(B) Drain plug
DI-00348
(A)
DI-00048

DI-20
DIFFERENTIALS
DIFFERENTIAL GEAR OIL
5) Fill the differential carrier with gear oil to the up-
per plug level.
NOTE:
•Carefully refill oil while watching the level. Ex-
cess or insufficient oil must be avoided.
•Use gear oil for the mechanical LSD for STi mod-
el.
Recommended oil:
Except for STi model:
GL-5 (75W-90) or equivalent
STi model:
GEAR OIL LSD (Part No. K0904AA080) or
equivalent
Oil capacity:
Except STi model:
0.8 2(0.8 US qt, 0.7 Imp qt)
STi model:
0.9 —1.1 2(1.0 —1.2 US qt, 0.8 —1.0 Imp
qt)
6) Install the filler plug or rear differential oil temper-
ature switch.
NOTE:
Apply fluid packing to the filler plug or rear differen-
tial oil temperature switch.
Fluid packing:
THREE BOND 1105 (Part No. 004403010) or
equivalent
Tightening torque:
49 N·m (5.0 kgf-m, 36.2 ft-lb)
7) Connect the oil temperature switch connector.
(STi model)
(A) Filler plug
(B) Drain plug
DI-00049
(A)
(B)
(A) Connector
DI-00348
(A)