Subaru Impreza 2004 User manual

FUJI HEAVY INDUSTRIES LTD. G1870GE4
2004 IMPREZA SERVICE MANUAL QUICK REFERENCE INDEX
TRANSMISSION SECTION
This service manual has been prepared
to provide SUBARU service personnel
with the necessary information and data
for the correct maintenance and repair
of SUBARU vehicles.
This manual includes the procedures
for maintenance, disassembling, reas-
sembling, inspection and adjustment of
components and diagnostics for guid-
ance of experienced mechanics.
Please peruse and utilize this manual
fully to ensure complete repair work for
satisfying our customers by keeping
their vehicle in optimum condition.
When replacement of parts during
repair work is needed, be sure to use
SUBARU genuine parts.
All information, illustration and specifi-
cations contained in this manual are
based on the latest product information
available at the time of publication
approval.
CONTROL SYSTEMS CS
AUTOMATIC TRANSMISSION 4AT
AUTOMATIC TRANSMISSION
(DIAGNOSTICS) 4AT(diag)
MANUAL TRANSMISSION AND
DIFFERENTIAL 5MT
MANUAL TRANSMISSION AND
DIFFERENTIAL 6MT
MANUAL TRANSMISSION AND
DIFFERENTIAL (DIAGNOSTICS) 6MT(diag)
CLUTCH SYSTEM CL

MANUAL TRANSMISSION AND
DIFFERENTIAL
6MT
Page
1. General Description ....................................................................................2
2. Transmission Gear Oil ..............................................................................31
3. Oil Seal......................................................................................................32
4. Vehicle Speed Sensor...............................................................................33
5. Transmission Mounting System ................................................................34
6. Manual Transmission Assembly ...............................................................36
7. Preparation for Overhaul...........................................................................41
8. Air Breather Hose......................................................................................42
9. Oil Pipe......................................................................................................43
10. Back-up Light Switch.................................................................................44
11. Neutral Position Switch .............................................................................46
12. Extension Case .........................................................................................48
13. Reverse Checking System........................................................................54
14. Transfer Drive Gear ..................................................................................57
15. Transfer Driven Gear ................................................................................59
16. Center Differential .....................................................................................61
17. Oil Pump ...................................................................................................62
18. Transmission Case ...................................................................................66
19. Main Shaft Assembly ................................................................................71
20. Driven Gear Assembly ..............................................................................85
21. Reverse Idler Gear Assembly ...................................................................93
22. Drive Pinion Shaft Assembly.....................................................................98
23. Front Differential Assembly .....................................................................104
24. Speedometer Gear..................................................................................110
25. Shifter Fork and Rod ...............................................................................112
26. Clutch Housing........................................................................................125
27. G Sensor .................................................................................................127
28. Driver’s Control Center Differential Control Module ................................129
29. General Diagnostic Table........................................................................130

6MT-71
MANUAL TRANSMISSION AND DIFFERENTIAL
Main Shaft Assembly
19.Main Shaft Assembly
A: REMOVAL
1) Remove the manual transmission assembly
from vehicle. <Ref. to 6MT-36, REMOVAL, Manual
Transmission Assembly.>
2) Prepare the transmission for overhaul. <Ref. to
6MT-41, Preparation for Overhaul.>
3) Remove the oil pipe, neutral position switch,
back-up light switch and harness. <Ref. to 6MT-43,
REMOVAL, Oil Pipe.>, <Ref. to 6MT-46, REMOV-
AL, Neutral Position Switch.>, <Ref. to 6MT-44,
REMOVAL, Back-up Light Switch.>
4) Remove the extension case. <Ref. to 6MT-48,
REMOVAL, Extension Case.>
5) Remove the transfer driven gear. <Ref. to 6MT-
59, REMOVAL, Transfer Driven Gear.>
6) Remove the center differential. <Ref. to 6MT-61,
REMOVAL, Center Differential.>
7) Remove the oil pump. <Ref. to 6MT-62, RE-
MOVAL, Oil Pump.>
8) Remove the transmission case. <Ref. to 6MT-
66, REMOVAL, Transmission Case.>
9) Remove the striking rod.
10) Using a screwdriver, shift to 4th gear position.
11) Remove the reverse idler holder.
12) Remove all checking plug, gasket, checking
spring, plunger and checking ball from adapter
plate.
NOTE:
Do not reuse the gasket.
13) Remove the bolt and gasket installing reverse
idler shaft.
14) Press the main shaft assembly, driven gear as-
sembly, reverse idler gear and each shifter fork,
then remove from the adapter plate at once.
NOTE:
Two people should do the work.
B: INSTALLATION
1) Adjust the 3rd-4th, and 5th-6th shifter fork rod.
<Ref. to 6MT-116, ADJUSTMENT, Shifter Fork
and Rod.>
(A) 3rd-4th shift rod
(A) Reverse idler holder
(A)
MT-00543
(A)
MT-00544
(A) Checking plug
(B) Gasket
(C) Checking spring
(D) Plunger
(E) Checking ball
(D) (E)
(A)
(A)
(B)
(B)
(C) (C)
MT-00545
MT-00546

6MT-72
MANUAL TRANSMISSION AND DIFFERENTIAL
Main Shaft Assembly
2) Turn the sub gear counterclockwise for approx.
three teeth. Align the sub gear and reverse idler
gear hole, then insert the ST.
ST 18757AA000 STRAIGHT PIN
3) Install the driven gear assembly to 1st-2nd
shifter fork assembly.
4) Install the main shaft assembly to 3rd-4th shifter
fork, and then assemble to driven gear assembly.
5) Install the 5th-6th shifter fork assembly to main
shaft assembly.
(A) Sub gear
(B) Reverse idler gear
(A) 1st-2nd shifter fork
(B) Driven gear assembly
(C) 1st-2nd sleeve
(A)
(B)
ST
MT-00547
MT-00548
(A)
(B)
(C)
(A) 3rd-4th shifter fork
(B) 3rd-4th sleeve
(C) Driven gear assembly
(D) Main shaft assembly
(A) 5th-6th shifter fork
(B) 5th-6th sleeve
(C) Main shaft assembly
MT-00549
(C)
(A) (B)
(C)
(D)
(D)
(A) (B)
MT-00550
(B)
(A)
(C)

6MT-73
MANUAL TRANSMISSION AND DIFFERENTIAL
Main Shaft Assembly
6) Install the reverse shifter fork assembly to re-
verse idler gear assembly.
7) Install the reverse idler gear assembly.
8) Install the thrust bearing of driven gear assem-
bly.
9) Press each shifter fork, main shaft assembly,
driven gear assembly and reverse idler gear as-
sembly, then install to the adapter plate at once.
NOTE:
Two people should do the work.
10) Install the plunger, checking spring, new gasket
and checking plug.
Tightening torque:
37 N·m (3.8 kgf-m, 27.3 ft-lb)
(A) Reverse idler gear assembly
(B) Reverse shifter fork
(C) Reverse sleeve
(A) Reverse idler gear assembly
(B) 1st drive gear
(C) Reverse gear
MT-00551
(A)
(B)
(C)
MT-00552
(B)
(A)
(C)
(A) Checking plug
(B) Gasket
(C) Checking spring
(D) Plunger
MT-00553
(D)
(A)
(B)
(C)

6MT-74
MANUAL TRANSMISSION AND DIFFERENTIAL
Main Shaft Assembly
11) Install the checking ball, checking spring, new
gasket and checking plug.
Tightening torque:
37 N·m (3.8 kgf-m, 27.3 ft-lb)
12) Install the bolt and new gasket.
Tightening torque:
25 N·m (2.5 kgf-m, 18.1 ft-lb)
13) Using a screwdriver, shift to 4th gear position.
14) Install the reverse idler holder
15) Install the striking rod.
16) Install the transmission case. <Ref. to 6MT-67,
INSTALLATION, Transmission Case.>
17) Install the selected main shaft snap ring and
washer.
18) Install the oil pump. <Ref. to 6MT-63, INSTAL-
LATION, Oil Pump.>
19) Install the center differential. <Ref. to 6MT-61,
INSTALLATION, Center Differential.>
20) Install the transfer driven gear. <Ref. to 6MT-
59, INSTALLATION, Transfer Driven Gear.>
21) Install the extension case. <Ref. to 6MT-48, IN-
STALLATION, Extension Case.>
22) Install the oil pipe, neutral position switch,
back-up light switch and harness. <Ref. to 6MT-43,
INSTALLATION, Oil Pipe.>, <Ref. to 6MT-46, IN-
STALLATION, Neutral Position Switch.>, <Ref. to
6MT-44, INSTALLATION, Back-up Light Switch.>
23) Install the manual transmission assembly to ve-
hicle. <Ref. to 6MT-38, INSTALLATION, Manual
Transmission Assembly.>
C: DISASSEMBLY
NOTE:
Each sleeve and hub engage at a specified point.
Mark an engagement point on the sleeve and hub
before disassembly.
1) Secure the ST on workbench.
ST 18664AA000 BASE
2) Lift the caulking of lock nut.
3) Set the main shaft assembly on ST, then remove
the lock nut and washer.
ST1 18665AA000 HOLDER
ST2 18664AA000 BASE
(A) Checking plug
(B) Gasket
(C) Checking spring
(D) Checking ball
MT-00554
(D)
(A)
(B)
(C)
MT-00546
(A) Reverse idler holder
(A)
MT-00544

6MT-75
MANUAL TRANSMISSION AND DIFFERENTIAL
Main Shaft Assembly
NOTE:
Use a 38 mm (1.50 in) socket wrench.
4) Remove the main shaft assembly from ST.
5) Set the ST1 on 6th drive gear, then remove the
taper roller bearing, bush and 6th drive gear using
press.
ST1 18722AA000 REMOVER
(TY856WX···model)
ST1 18722AA010 REMOVER
(TY856WN···model)
ST2 899864100 REMOVER
6) Remove the 5th-6th sleeve, 6th needle bearing
and 6th baulk ring.
7) Set the ST on 3rd drive gear, then remove each
part using press.
ST 18720AA000 REMOVER
(A) Taper roller bearing
(B) Bush
(C) 6th drive gear
MT-00556
ST2
ST1
MT-00557
(A)
(B) (C)
ST1
ST2
ST1
(A) Needle bearing
(B) 6th baulk ring
(C) 5th-6th sleeve
(A) 3rd drive gear
(B) 3rd-4th sleeve
(A)
(B)
(C)
MT-00558
MT-00559
(A)
ST
(B)
(B)
ST

6MT-76
MANUAL TRANSMISSION AND DIFFERENTIAL
Main Shaft Assembly
D: ASSEMBLY
NOTE:
Replace the following parts as a set.
•Sleeve and hub
•Outer baulk ring, 3rd synchro cone and inner
baulk ring
•Taper roller bearing
1) Sufficiently apply gear oil to the main shaft, 3rd
needle bearing and inner periphery of 3rd drive
gear.
2) Install the 3rd needle bearing and 3rd drive gear
to main shaft.
3) Install the inner baulk ring, 3rd synchro cone and
outer baulk ring.
NOTE:
Install the 3rd synchro cone, by aligning protrusion
portions of the 3rd synchro cone with 3rd drive gear
hole portion.
4) Install the 3rd-4th hub and 4th bush.
(1) Set to the main shaft, taking care of 3rd-4th
hub installing direction.
(A) 3rd needle bearing
(B) 3rd drive gear
(A) Inner baulk ring
(B) Outer baulk ring
(A)
(B)
MT-00560
(A)
(B)
MT-00561
(A) Main shaft
(B) 3rd-4th hub
(C) 3rd drive gear
MT-00562
MT-00884
(A)
(B)
(C)

6MT-77
MANUAL TRANSMISSION AND DIFFERENTIAL
Main Shaft Assembly
(2) Set to the main shaft, taking care not to
overlap the main shaft oil hole and 4th bush oil
hole.
(3) Using the ST, press in the 3rd-4th hub and
4th bush at once.
ST1 18651AA000 INSTALLER
ST2 398177700 INSTALLER
CAUTION:
Do not apply pressure in excess of 40 kN (4.0
ton, 4.4 US ton, 3.9 Imp ton).
NOTE:
When pressing in 3rd-4th hub and 4th bush, align
the protrusion portion of outer baulk ring and cutout
portion of 3rd-4th bush by moving the outer baulk
ring.
5) Make sure the 3rd drive gear is smoothly turned
by hand. If not, reassemble.
(A) 4th bush
(B) 3rd-4th hub
(C) 4th bush oil hole
(D) Main shaft oil hole
MT-00885
(A)
(B)
A
(D)
(C)
A
(C)
(C) (D)
A - A
(A)
(A) 3rd-4th hub
(B) Outer baulk ring
(C) Cutout portion of 3rd-4th hub
(D) Protrusion portion of outer baulk ring
(E) 4th bush
MT-00555
(D)
(C)
(A)
(E)
(E)
(A)
(B)
ST1
ST2

6MT-78
MANUAL TRANSMISSION AND DIFFERENTIAL
Main Shaft Assembly
6) Install the 3rd-4th shifting insert key in proper
place of 3rd-4th sleeve.
NOTE:
Angle of each shifting insert key is 120°apart.
7) Install the 3rd-4th sleeve to 3rd-4th hub.
NOTE:
•3rd-4th sleeve has a groove for identification.
•Install the 3rd-4th sleeve with groove facing to
3rd drive gear side.
8) Install the 4th baulk ring.
9) Sufficiently apply gear oil to the main shaft, 4th
needle bearing and inner periphery of 4th drive
gear.
10) Install the 4th needle bearing and 4th drive
gear.
(A) 3rd-4th sleeve
(B) 3rd-4th shifting insert key
(A) 3rd drive gear
(B) Groove (1) for identification of 3rd-4th sleeve
MT-00673
(B)
(A)
MT-00563
(A)
(B)
(A) 4th needle bearing
(B) 4th drive gear
MT-00564
(A)
(B)
MT-00565