Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Service manual — part 435

6MT-77

Main Shaft Assembly

MANUAL TRANSMISSION AND DIFFERENTIAL

32) Using the ST, crimp the lock nut in 4 locations,

with dimensions within A 27±0.3 mm (1.06±0.01

in).

ST 18668AA000 PUNCH
NOTE:

Do not damage the crimp area of the lock nut.

E: INSPECTION

Disassembled parts should be washed with clean-

ing solvent first, then inspected carefully.

1) Bearing

Replace the bearings in the following cases.

• Wear, rusting or damage of the bearings

• The bearing does not rotate smoothly or an ab-

normal noise is emitted when turning.

• The bearing has other defects.

2) Bushing (each gear)

Replace the bushing in following cases.

• The sliding surface is damaged or abnormally

worn.

3) Gear

Replace gears in the following cases.

• The gear teeth surface is damaged or excessive-

ly worn.

• The contact area of the baulk ring is damaged.

• The inner face of the gear is worn.

4) Baulk ring, synchro cone

Replace the baulk ring and synchro cone in the fol-

lowing cases.

• Wear, rusting or damage of the baulk ring

5) Shifting insert key

Replace the shifting insert key if deformed, exces-

sively worn or defective in any way.

F: ADJUSTMENT

1. MAIN SHAFT SNAP RING & ADJUSTING

WASHER SELECTION

NOTE:

In the following conditions, perform the procedures

below.

• 1st to 6th driven gear replacement

• 1st and 2nd synchro ring assembly replacement

• Ball bearing replacement

• Adapter plate replacement

• Driven shaft replacement

1) Insert the drive pinion assembly into the adapter

plate.
NOTE:

Confirm that the thrust bearing outer race has not

been removed and the drive pinion is not lifted.

MT-00580

A

A

ST

MT-00581

6MT-78

Main Shaft Assembly

MANUAL TRANSMISSION AND DIFFERENTIAL

2) Set the height gauge to the adapter plate. Lower

the height gauge indicator to the mating surface of

the adapter plate and case, and set to zero points.

ST 18853AA000 HEIGHT GAUGE

NOTE:

• The adapter plate will be the base point for the

measurement. Use a scraper to remove any gasket

material remaining on the end face.

• During measurement, do not place the height

gauge in the shaded area shown in the figure.

3) Measure the height to the ball bearing end face

(height H).

NOTE:

Set the height gauge indicator near the measure-

ment target, and lock dial (1) as shown in the figure.

Turn dial (2), and set the indicator to the end face of

the bearing.

Turn approximately 120° at a time, and measure

the ball bearing in 5 locations. Round down the 2

highest and 2 lowest measurement values. The re-

maining center value is used as the measurement

value.

MT-00582

ST

MT-00583

(A) Ball bearing

(A)

MT-00955

H

MT-00585

(2)

(1)

6MT-79

Main Shaft Assembly

MANUAL TRANSMISSION AND DIFFERENTIAL

4) According to the measurement value, select the

snap ring and adjusting washer from the following

table.

Snap ring

H: mm (in)

Part No.

Thickness: mm (in)

270.83 — 271.40

(10.66 — 10.69)

805072010

1.65

(0.065)

271.41 — 271.98

(10.69 — 10.71)

805072011

1.95

(0.077)

271.99 — 272.56

(10.71 — 10.73)

805072012

2.25

(0.089)

Adjusting washer

H: mm (in)

Part No.

Thickness: mm

(in)

270.83 — 271.40

(10.66 — 10.69)

803067012

1.6

(0.063)

271.41 — 271.98

(10.69 — 10.71)

803067011

1.3

(0.051)

271.99 — 272.56

(10.71 — 10.73)

803067010

1.0

(0.039)

6MT-80

Driven Gear Assembly

MANUAL TRANSMISSION AND DIFFERENTIAL

18.Driven Gear 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 driven gear assembly. <Ref. to

6MT-65, REMOVAL, Main Shaft Assembly.>

9) Remove the 1st needle bearing.

10) Remove the thrust needle bearing.

B: INSTALLATION

1) Adjust the main shaft snap ring. <Ref. to 6MT-

77, ADJUSTMENT, Main Shaft Assembly.>

2) Adjust the 1st-2nd shifter rod. <Ref. to 6MT-112,

ADJUSTMENT, Shifter Fork and Rod.>

3) Install the thrust needle bearing.
NOTE:

Confirm that the thrust needle bearing is installed in

the proper direction.

4) Install the 1st needle bearing.

5) Install the driven gear assembly. <Ref. to 6MT-

66, INSTALLATION, Main Shaft Assembly.>

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

INSTALLATION, Transmission Case.>

7) Adjust the backlash of the driven gear assembly

in the axial direction. <Ref. to 6MT-88, ADJUST-

MENT, Driven Gear Assembly.>

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

INSTALLATION, Center Differential.>

9) Install the transfer driven gear. <Ref. to 6MT-55,

INSTALLATION, Transfer Driven Gear.>

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

STALLATION, Extension Case.>

11) 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.>

12) 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.

3) Attach ST3 to the lock nut, set the driven gear

assembly to the ST, and remove the lock nut.

ST1 18666AA000

HOLDER

ST2 18664AA000

BASE

ST3 18620AA000

ADAPTER WRENCH

MT-00586

MT-00587

MT-00588

ST3

ST2

ST1