Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 432

6MT-65

Main Shaft Assembly

MANUAL TRANSMISSION AND DIFFERENTIAL

17.Main Shaft Assembly

A: REMOVAL

1) Remove the manual transmission assembly

from the vehicle. <Ref. to 6MT-31, REMOVAL,

Manual Transmission Assembly.>

2) Prepare the transmission for overhaul. <Ref. to

6MT-37, Preparation for Overhaul.>

3) Remove the neutral position switch, back-up

light switch and harness. <Ref. to 6MT-41, RE-

MOVAL, Neutral Position Switch.> <Ref. to 6MT-

39, REMOVAL, Back-up Light Switch.>

4) Remove the extension case. <Ref. to 6MT-43,

REMOVAL, Extension Case.>

5) Remove the transfer driven gear. <Ref. to 6MT-

55, REMOVAL, Transfer Driven Gear.>

6) Remove the center differential. <Ref. to 6MT-57,

REMOVAL, Center Differential.>

7) Remove the transmission case. <Ref. to 6MT-

58, REMOVAL, Transmission Case.>

8) Remove the striking rod.

9) Remove the oil guide B.

10) Use a screwdriver to shift to the 4th gear posi-

tion.

11) Remove the reverse idler holder.

12) Remove the check plug, O-ring, check spring,

plunger and check ball from the adapter plate.
NOTE:

Do not reuse the O-ring.

(A) 3rd-4th shift rod

MT-01623

MT-01736

(A)

(A) Reverse idler holder

(A) Check plug
(B) O-ring

(C) Checking spring
(D) Plunger

(E) Check ball

MT-00544

(A)

(D)

(E)

(A)

(A)

(B)

(B)

(C)

(C)

MT-01931

6MT-66

Main Shaft Assembly

MANUAL TRANSMISSION AND DIFFERENTIAL

13) Remove the bolt and gasket holding the re-

verse idler shaft.

14) Push the main shaft assembly, driven gear as-

sembly, reverse idler gear and shifter forks to re-

move from the adapter plate all at once.
NOTE:

A helper is required to perform this work.

B: INSTALLATION

1) Adjust the 3rd-4th and 5th-6th shifter fork rods.

<Ref. to 6MT-112, ADJUSTMENT, Shifter Fork

and Rod.>

2) Turn the sub gear counterclockwise for approxi-

mately 3 teeth. Match the sub gear and reverse

idler gear holes, and insert the ST.

ST 18757AA000 STRAIGHT PIN

3) Attach the driven gear assembly to the 1st-2nd

shifter fork assembly.

4) Attach the main shaft assembly to the 3rd-4th

shifter fork, and assemble to the driven gear as-

sembly.

(A) Sub gear
(B) Reverse idler gear

MT-00546

MT-00547

(A)

(B)

ST

(A) 1st-2nd shifter fork
(B) Driven gear ASSY

(C) 1st-2nd sleeve

(A) 3rd-4th shifter fork
(B) 3rd-4th sleeve

(C) Driven gear ASSY
(D) Main shaft ASSY

MT-00548

(A)

(B)

(C)

MT-00549

(C)

(A)

(B)

(C)

(D)

(D)

(A)

(B)

6MT-67

Main Shaft Assembly

MANUAL TRANSMISSION AND DIFFERENTIAL

5) Attach the 5th-6th shifter fork assembly to the

main shaft assembly.

6) Attach the reverse shifter fork assembly to the

reverse idler gear assembly.

7) Install the reverse idler gear assembly.

8) Install the thrust bearing of the driven gear as-

sembly.

9) Push on the shifter forks, main shaft assembly,

driven gear assembly and reverse idler gear as-

semblies, to attach to the adapter plate all at once.
NOTE:

A helper is required to perform this work.

10) Install the plunger, check spring, new O-ring

and check plugs.
Tightening torque:

25 N·m (2.5 kgf-m, 18.4 ft-lb)

(A) 5th-6th shifter fork
(B) 5th-6th sleeve

(C) Main shaft ASSY

(A) Reverse idler gear ASSY
(B) Reverse shifter fork

(C) Reverse sleeve

(A) Reverse idler gear ASSY
(B) 1st drive gear

(C) Reverse gear

MT-00550

(B)

(A)

(C)

MT-00551

(A)

(B)

(C)

MT-00552

(B)

(A)

(C)

(A) Check plug
(B) O-ring

(C) Checking spring
(D) Plunger

MT-01932

(D)

(A)

(B)

(C)

6MT-68

Main Shaft Assembly

MANUAL TRANSMISSION AND DIFFERENTIAL

11) Install the check ball, check spring, new O-ring

and check plugs.
Tightening torque:

25 N·m (2.5 kgf-m, 18.4 ft-lb)

12) Attach the bolt and a new gasket.
Tightening torque:

25 N·m (2.5 kgf-m, 18.4 ft-lb)

13) Use a screwdriver to shift to the 4th gear posi-

tion.

14) Install the reverse idler holder.

15) Install the oil guide B.
Tightening torque:

18 N·m (1.8 kgf-m, 13.3 ft-lb)

16) Install the striking rod.

17) Install the transmission case. <Ref. to 6MT-60,

INSTALLATION, Transmission Case.>

18) Install the selected main shaft snap ring and

washers.

19) Install the center differential. <Ref. to 6MT-57,

INSTALLATION, Center Differential.>

20) Install the transfer driven gear. <Ref. to 6MT-

55, INSTALLATION, Transfer Driven Gear.>

21) Install the extension case. <Ref. to 6MT-43, IN-

STALLATION, Extension Case.>

22) Install the neutral position switch, back-up light

switch and harness. <Ref. to 6MT-41, INSTALLA-

TION, Neutral Position Switch.> <Ref. to 6MT-39,

INSTALLATION, Back-up Light Switch.>

23) Install the manual transmission assembly to the

vehicle. <Ref. to 6MT-33, INSTALLATION, Manual

Transmission Assembly.>

C: DISASSEMBLY

NOTE:

Individual sleeves and hubs meet at a specified po-

sition. Before disassembly, mark the meeting posi-

tion of the sleeve and hub.

1) Affix the ST to the work table.

ST 18664AA000 BASE

2) Flatten the tab of the lock nut.

(A) Check plug
(B) O-ring

(C) Checking spring
(D) Check ball

MT-00554

(D)

(A)

(B)

(C)

MT-00546

(A) Reverse idler holder

MT-00544

(A)

MT-01623