Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 407

5MT-49

Transmission Case

MANUAL TRANSMISSION AND DIFFERENTIAL

14.Transmission Case

A: REMOVAL

1) Remove the manual transmission assembly

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

Manual Transmission Assembly.>

2) Remove the clutch release lever. <Ref. to CL-

15, REMOVAL, Release Bearing and Lever.>

3) Remove the transfer case together with the ex-

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

AL, Transfer Case and Extension Case

Assembly.>

4) Remove the bearing mounting bolt.

5) Remove the main shaft rear plate.

6) Remove the bolts and nuts, and separate the

transmission case into the right and left case.

7) Remove the drive pinion shaft assembly from

the left side of the transmission case.
NOTE:

Use a hammer handle, etc. to remove if too tight.

8) Remove the main shaft assembly for single-

range.

9) Remove the front differential assembly.

10) Remove the differential side retainers and

bearing outer races on the left and right side. <Ref.

to 5MT-69, REMOVAL, Front Differential Assem-

bly.>
NOTE:

Do not confuse the right and left roller bearing outer

races.

11) Remove the reverse idler gear. <Ref. to 5MT-

77, REMOVAL, Reverse Idler Gear.>

12) Remove the shifter fork and rod. <Ref. to 5MT-

79, REMOVAL, Shifter Fork and Rod.>

(A) Main shaft rear plate

MT-01514

(A)

MT-01515

MT-00160

(A) Main shaft ASSY for single-range
(B) Drive pinion shaft ASSY

MT-00161

( A )

( B )

MT-00162

5MT-50

Transmission Case

MANUAL TRANSMISSION AND DIFFERENTIAL

B: INSTALLATION

1) Wipe off grease, oil and dust on the mating sur-

faces of transmission cases with cleaning solvent.

2) Install the shifter fork and rod. <Ref. to 5MT-80,

INSTALLATION, Shifter Fork and Rod.>?

3) Install the reverse idler gear. <Ref. to 5MT-77,

INSTALLATION, Reverse Idler Gear.>

4) Select the drive pinion shim. <Ref. to 5MT-58,

INSTALLATION, Drive Pinion Shaft Assembly.>

5) Install the differential side retainer, from which

the bearing outer race and O-ring have already

been removed, to the transmission case LH side.

6) Install the front differential assembly.

7) Install the main shaft assembly for single-range.

Align the transmission case knock pin into the

knock pin hole of the needle bearing.

8) Install the selected drive pinion shims and drive

pinion shaft assembly.
NOTE:

Align the roller bearing knock pin hole to the trans-

mission case knock pin.

9) Tighten the left and right side of the transmission

case with the17 mounting bolts.
NOTE:

• Insert bolts (11) and (16) from the LH side of the

transmission case.

• Match the cases together so that the drive pinion

shims are not caught between the cases.
Tightening torque:

8 mm bolt

25 N·m (2.5 kgf-m, 18.4 ft-lb)

10 mm bolt

39 N·m (4.0 kgf-m, 28.8 ft-lb)

10) Install the bearing outer race to the RH side of

the transmission case.

11) Tighten the bearing mounting bolts.
Tightening torque:

30 N·m (3.1 kgf-m, 22.1 ft-lb)

12) Adjust the backlash of the hypoid gear and the

preload of the roller bearing.

(1) Attach the ST on drive pinion assembly.

ST 498427100

STOPPER

(2) Place the transmission with the LH side of

case facing downward, and put ST1 on the

bearing outer race.

(9)

(7)

(5)

(16)

(17)

(11)

(3)

(4)

(2)

(1)

(12)

(8)

(6)

(10)

(14)

(15)

(13)

MT-00178

MT-01514

ST

MT-01516

5MT-51

Transmission Case

MANUAL TRANSMISSION AND DIFFERENTIAL

(3) Screw the retainer assembly from the bot-

tom into left case using ST2. Fit the ST3 on

transmission main shaft. Shift the gear into 4th

or 5th, and turn the shaft several times. Screw

in the retainer while rotating the ST3 until a

slight resistance is felt on ST2.

This is the contact point of the hypoid gear and

the drive pinion shaft. Repeat the above se-

quence several times to ensure the contact

point.

ST1 399780104

WEIGHT

ST2 18630AA010 WRENCH COMPL RETAIN-

ER

ST3 499927100

HANDLE

(4) Remove the WEIGHT, and screw in the side

retainer without the O-ring into the RH side of

the transmission case, and stop at the point

where a slight resistance is felt.

NOTE:

In this condition, the backlash between hypoid gear

and drive pinion shaft is zero.

ST 18630AA010 WRENCH COMPL RETAIN-

ER

(5) Loosen the side retainer on the LH side of

the transmission case by 3 notches, and turn

the side retainer on the RH side of the transmis-

sion case by the same notches in order to apply

backlash.

(6) Screw in the side retainer of the RH side of

the transmission case additionally by 1 notch in

order to apply preload on taper roller bearing.

(7) Tighten temporarily both the upper and low-

er lock plates, and put marks on both the side

retainer and lock plate for later readjustment.

NOTE:

If it is hard to install the lock plates, reverse the

sides and install them.

(8) Turn the transmission main shaft several

times while tapping around the retainer lightly

with plastic hammer.

13) Inspect and adjust backlash and tooth contact

of the hypoid gear. <Ref. to 5MT-73, INSPECTION,

Front Differential Assembly.>

14) Separate the transmission case into left and

right parts. <Ref. to 5MT-49, REMOVAL, Transmis-

sion Case.>

15) Select a main shaft rear plate. <Ref. to 5MT-57,

ADJUSTMENT, Main Shaft Assembly for Single-

Range.>

16) Check each shifter fork. <Ref. to 5MT-81, IN-

SPECTION, Shifter Fork and Rod.>

17) Apply liquid gasket, then join the right side and

left side of the case together.
Liquid gasket:

THREE BOND 1215 (Part No. 004403007) or

equivalent

MT-02407

ST3

ST2

ST1

MT-00176

ST

MT-02616

5MT-52

Transmission Case

MANUAL TRANSMISSION AND DIFFERENTIAL

18) With brackets and clips as shown in the figure,

tighten the seventeen bolts.
NOTE:

• Insert bolts (11) and (16) from the LH side of the

transmission case.

• Match the cases together so that the drive pinion

shims are not caught between the cases.
Tightening torque:

8 mm bolt

25 N·m (2.5 kgf-m, 18.4 ft-lb)

10 mm bolt

39 N·m (4.0 kgf-m, 28.8 ft-lb)

19) Tighten the bearing mounting bolts.
Tightening torque:

30 N·m (3.1 kgf-m, 22.1 ft-lb)

20) Remove the lock plate. Then loosen the retain-

er until the O-ring groove appears. Fit the O-ring

into the groove and tighten the retainer into the po-

sition where it was not loosened.
NOTE:

• When loosening the retainer, record the number

of the turns made.

• Perform this for both left and right side retainers.

• Use new O-rings.

21) Install the lock plate.
Tightening torque:

T: 25 N·m (2.5 kgf-m, 18.4 ft-lb)

22) Install the transfer case together with the exten-

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

TION, Transfer Case and Extension Case

Assembly.>

23) Install the clutch release lever and bearing.

<Ref. to CL-15, INSTALLATION, Release Bearing

and Lever.>

24) Install the manual transmission assembly to the

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

Transmission Assembly.>

C: INSPECTION

Check the transmission case for cracks, damage,

or oil leaks.

MT-00172

(9)

(7)

(5)

(1)

(2)

(16)

(17)

(11)

(3)

(4)

(12)

(8)

(6)

(10)

(14)

(15)

(13)

MT-01514

MT-00177

T