Subaru Legacy IV (2008 year). Service manual — part 797

5MT-84

General Diagnostic Table

MANUAL TRANSMISSION AND DIFFERENTIAL

2. DIFFERENTIAL

Symptoms

Possible cause

Corrective action

1. Broken differential (case, gear, bear-
ing, etc.)

NOTE:
Noise will occur, and eventually the differ-
ential will not be able to operate due to
broken pieces obstructing the gear revo-
lution.

(a) Insufficient or improper oil

Disassemble the differential and replace
broken components. At the same time
check other components for any trouble,
and replace if necessary.

(b) Use of vehicle under severe condi-
tions such as excessive load and
improper use of the clutch

Readjust the preload and backlash of the
bearing, and the contact surface of gear.

(c) Improper adjustment of taper roller
bearing

Adjust.

(d) Improper adjustment of the drive pin-
ion and the hypoid driven gear

Adjust.

(e) Excessive backlash of a vehicle under
severe operating conditions due to worn
differential side gear, washer or differen-
tial pinion.

Add recommended oil to the specified
level. Do not use vehicle under severe
operating conditions.

(f) Loose hypoid driven gear tightening
bolts

Tighten.

2. Differential and hypoid gear noises
Troubles of the differential and hypoid
gear always appear as noise problems.
Therefore noise is the first indication of
trouble. However, noises from the engine,
muffler, tire, exhaust gas, bearing, body,
etc. are easily mistaken for the differential
noise. Pay special attention to the hypoid
gear noise because it is easily confused
with other gear noises. There are the fol-
lowing four kinds of noises.
• Gear noise when driving:
If noise increases as the vehicle speed
increases, it may be due to insufficient
gear oil, incorrect gear engagement,
damaged gears, etc.
• Gear noise when coasting:
Damaged gears due to misadjusted bear-
ings and incorrect shim adjustment.
• Bearing noise when driving or coasting:
Cracked, broken or damaged bearings
• Noise mainly when turning:
Noise from differential side gear, differen-
tial pinion or differential pinion shaft, etc.

(a) Insufficient oil

Lubricate.

(b) Improper adjustment of hypoid driven
gear and drive pinion

Check the tooth contact.

(c) Worn teeth of hypoid driven gear and
drive pinion

Replace as a set.
Readjust the bearing preload.

(d) Loose roller bearing

Readjust the backlash of the hypoid
driven gear to drive pinion, and check the
tooth contact.

(e) Distorted hypoid driven gear or differ-
ential case

Replace.

(f) Worn washer and differential pinion
shaft

Replace.

6MT-2

General Description

MANUAL TRANSMISSION AND DIFFERENTIAL

1. General Description

A: SPECIFICATION

1. MANUAL TRANSMISSION AND FRONT DIFFERENTIAL

2. TRANSMISSION GEAR OIL

Recommended oil:

GL-5 (75W-90) or equivalent

Type

6-forward speeds and 1-reverse

Transmission gear ratio

1st

3.636

2nd

2.235

3rd

1.521

4th

1.137

5th

0.891

6th

0.707

Rev.

3.545

Front reduction
gear

Final

Type of gear

Hypoid

Gear ratio

3.900

Rear reduction
gear

Transfer

Type of gear

Helical

Gear ratio

1.100

Final

Type of gear

Hypoid

Gear ratio

3.545

Front differential

Type and number of gear

Straight bevel gear

(Bevel pinion: 4, Bevel gear: 2)

Center differential

Type and number of gear

Straight bevel gear

(Bevel pinion: 2, bevel gear: 2 and viscous LSD)

Transmission gear oil

GL-5

Transmission gear oil capacity

4.1

2 (4.3 US qt, 3.6 Imp qt)

6MT-3

General Description

MANUAL TRANSMISSION AND DIFFERENTIAL

B: COMPONENT

1. CLUTCH HOUSING

(1)

Oil level gauge

(7)

Oil seal

Tightening torque:N·m (kgf-m, ft-lb)

(2)

Plug

(8)

Clutch release bearing guide

T1: 6.4 (0.7, 4.7)

(3)

Pitching stopper bracket

(9)

Return spring bracket

T2: 41 (4.2, 30.2)

(4)

Clip

(10)

O-ring

T3: 50 (5.1, 36.9)

(5)

Clutch housing

(11)

Drain plug

T4: 70 (7.1, 51.6)

(6)

Gasket

MT-01809

(1)

(5)

(6)

(7)

(8)

T3

T4

T1

(4)

(3)

(2)

(9)

T2

(10)

(11)

6MT-4

General Description

MANUAL TRANSMISSION AND DIFFERENTIAL

2. ADAPTER PLATE

(1)

Breather hose

(7)

Check plug

(13)

Adapter plate

(2)

Transmission harness stay

(8)

O-ring

(3)

Check plug

(9)

Check spring

Tightening torque:N·m (kgf-m, ft-lb)

(4)

O-ring

(10)

Check ball

T1: 18 (1.8, 13.3)

(5)

Check spring

(11)

Oil guide A

T2: 25 (2.5, 18.4)

(6)

Plunger

(12)

Oil guide B

T3: 50 (5.1, 36.9)

MT-01609

(2)

(3)

(4)

(1)

(5)

(7)

(6)

(8)

(9)

(10)

(13)

T2

T1

T3

T2

T1

T3

(12)

T1

(11)