Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 408

5MT-53

Main Shaft Assembly for Single-Range

MANUAL TRANSMISSION AND DIFFERENTIAL

15.Main Shaft Assembly for Sin-

gle-Range

A: REMOVAL

1) Remove the manual transmission assembly

from the vehicle. <Ref. to 5MT-23, REMOVAL,

Manual Transmission Assembly.>

2) Remove the transfer case together with the ex-

tension case assembly. <Ref. to 5MT-35, REMOV-

AL, Transfer Case and Extension Case

Assembly.>

3) Remove the transmission case. <Ref. to 5MT-

49, REMOVAL, Transmission Case.>

4) Remove the drive pinion shaft assembly. <Ref.

to 5MT-58, REMOVAL, Drive Pinion Shaft Assem-

bly.>

5) Remove the main shaft assembly for single-

range.

B: INSTALLATION

1) Install the needle bearing and oil seal to the front

of the transmission single-range main shaft assem-

bly.
NOTE:

• Wrap the clutch splined section with vinyl tape to

prevent damage to the oil seal.

• Apply NICHIMOLY N-130 or the equivalent to

the sealing lip of the oil seal.

• Use a new oil seal.

2) Align the transmission case knock pin into the

knock pin hole of the needle bearing outer race.
NOTE:

Align the end face of the seal with surface (A) when

installing the oil seal.

3) Install the drive pinion shaft assembly. <Ref. to

5MT-58, INSTALLATION, Drive Pinion Shaft As-

sembly.>

4) Install the transmission case. <Ref. to 5MT-50,

INSTALLATION, Transmission Case.>

5) Install the transfer case together with the exten-

sion case assembly. <Ref. to 5MT-35, INSTALLA-

TION, Transfer Case and Extension Case

Assembly.>

6) Install the manual transmission assembly to the

vehicle. <Ref. to 5MT-26, INSTALLATION, Manual

Transmission Assembly.>

C: DISASSEMBLY

1) Put vinyl tape around main shaft spline to protect

the oil seal from damage. Then pull out the oil seal

and needle bearing by hand.

2) Remove the lock nut and lock washer from

transmission main shaft assembly for single-range.
NOTE:

Flatten the lock nut tab before removing the lock

nut.

ST1 498937000

TRANSMISSION HOLDER

ST2 499987003

SOCKET WRENCH (35)

3) Remove the 5th hub & sleeve No. 2, baulk lever,

baulk ring, 5th drive gear and needle bearing.

MT-00185

(A)

(A) 5th hub & sleeve No. 2
(B) Baulk ring

(C) 5th drive gear

ST2

ST1

MT-01517

( A )

( B )

( C )

MT-01518

5MT-54

Main Shaft Assembly for Single-Range

MANUAL TRANSMISSION AND DIFFERENTIAL

4) Using ST1 and ST2, remove the rest of the

parts.
NOTE:

• When replacing the sleeve & hub, replace them

as a set.

• Do not disassemble the sleeve & hub; the align-

ing position is pre-matched.

• If it is necessary to disassemble, mark the en-

gaging points on the splines beforehand.

ST1 899864100

REMOVER

ST2 899714110

REMOVER

D: ASSEMBLY

1) When the sleeve & hub assemblies have been

disassembled, reassemble by aligning the align-

ment marks.
NOTE:

Position the open ends of the spring 120° apart.

2) Install the 3rd drive gear, outer baulk ring, syn-

chro cone, inner baulk ring, sleeve & hub assembly

for the 3rd needle bearing, on the transmission

main shaft.
NOTE:

Align the groove in baulk ring with the shifting in-

sert.

(A) Press

MT-00190

(A)

ST2

ST1

(A) 3rd-4th coupling sleeve & synchronizer hub

ASSY

(B) 3rd gear side

(A) 3rd needle bearing
(B) 3rd drive gear

(C) Inner baulk ring
(D) Synchro cone

(E) Outer baulk ring

(F) Sleeve & hub ASSY

MT-01852

(A)

(B)

MT-01318

(A)

(B)

(C)

(D)

(E)

(F)

5MT-55

Main Shaft Assembly for Single-Range

MANUAL TRANSMISSION AND DIFFERENTIAL

3) Install the 4th needle bearing race onto trans-

mission main shaft using ST1, ST2 and press.
CAUTION:

Do not apply a load in excess of 10 kN (1 ton, 1.1

US ton, 1.0 Imp ton).

ST1 899714110

REMOVER

ST2 499877000

RACE 4-5 INSTALLER

4) Install the baulk ring, needle bearing, 4th drive

gear and 4th gear thrust washer to the transmission

main shaft.
NOTE:

• Align the baulk ring and hub & sleeve assembly

with the key groove.

• Make sure the thrust washer is facing the correct

direction.

5) Press-fit the double taper roller bearing into the

rear section of transmission main shaft using ST1,

ST2 and a press.
CAUTION:

Do not apply a load in excess of 10 kN (1 ton, 1.1

US ton, 1.0 Imp ton).
NOTE:

Use a new double taper roller bearing.

ST1 899714110

REMOVER

ST2 499877000

RACE 4-5 INSTALLER

6) Install the 5th needle bearing race into the rear

section of transmission main shaft using ST1 and

ST2.
CAUTION:

Do not apply a load in excess of 10 kN (1 ton,

1.1 US ton, 1.0 Imp ton).
NOTE:

Make sure the thrust washer is facing the correct

direction.

ST1 899714110

REMOVER

ST2 499877000

RACE 4-5 INSTALLER

(A) 4th needle bearing race

(A) Groove
(B) Face this surface to the 4th gear side.

MT-00192

(A)

ST1

ST2

MT-02132

(A)

(B)

(A) Face this surface to the 5th gear side.

MT-00194

ST1

ST2

MT-00195

(A)

5MT-56

Main Shaft Assembly for Single-Range

MANUAL TRANSMISSION AND DIFFERENTIAL

7) Install rest of the parts to the rear section of the

transmission main shaft.
CAUTION:

• Install the baulk lever so that the concave

side faces toward the 5th hub.

• Align the protruded section of baulk ring be-

tween the baulk levers.

8) Tighten the lock nuts to the specified torque us-

ing ST1 and ST2.
NOTE:

Use new lock nuts and lock washers.

ST1 499987003

SOCKET WRENCH (35)

ST2 498937000

TRANSMISSION HOLDER

Tightening torque:

120 N·m (12.2 kgf-m, 88.5 ft-lb)

9) Crimp lock nuts in two locations after tightening.
CAUTION:

When crimping the lock nut, be careful not to

crack it.

E: INSPECTION

Disassembled parts should be washed with clean-

ing solvent first, then inspected carefully.

1) Bearing

Replace the bearings in the following cases.

• When the bearing balls, outer races and inner

races are broken or rusty.

• When the bearing is worn.

• When the bearings fail to turn smoothly or emit

noise in rotation after gear oil lubrication.

• When bearing has other defects.

2) Bushing (each gear)

Replace the bushing in following cases.

• When the sliding surface is damaged or abnor-

mally worn.

• When the inner wall is abnormally worn.

3) Gear

Replace gears in the following cases.

• Replace the gear with new part if its tooth surfac-

es are broken, damaged or excessively worn.

• Correct or replace if the cone that contacts the

baulk ring is rough or damaged.

• Correct or replace if the inner surface or end face

is damaged.

4) Baulk ring

Replace the baulk ring in the following cases.

• When the inner surface and end face are dam-

aged.

(A) Baulk lever
(B) 5th hub

(A) Baulk ring
(B) Baulk lever

(C) 5th hub

(A) Needle bearing
(B) 5th drive gear

(C) Baulk ring
(D) 5th hub & sleeve No. 2

(E) Lock washer

(F) Lock nut

(G) Baulk lever

(H) Nut side

(A)

(B)

MT-01522

MT-01531

(A)

(B)

(C)

(B)

MT-02771

(D)

(A) (B) (C)

(E)

(F)

(G)

(H)

(A) Lock nut
(B) Outer dimension after crimping

(B)

(A)

MT-02707