Subaru Legacy III (2000-2003 year). Manual - part 636
MT-112
MANUAL TRANSMISSION AND DIFFERENTIAL
GENERAL DIAGNOSTIC
2. DIFFERENTIAL
Symptom
Possible cause
Remedy
1. Broken differential (case, gear, bear-
ing, etc.)
NOTE:
Abnormal noise will develop and finally it
will become impossible to continue to run
due to broken pieces obstructing the gear
revolution.
(a) Insufficient or improper oil
Disassemble differential and replace bro-
ken components and 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 clutch
Readjust bearing preload and backlash
and face contact of gears.
(c) Improper adjustment of taper roller
bearing
Adjust.
(d) Improper adjustment of drive pinion
and hypoid driven gear
Adjust.
(e) Excessive backlash due to worn dif-
ferential side gear, washer or differential
pinion vehicle under severe operating
conditions.
Add recommended oil to specified level.
Do not use vehicle under severe operat-
ing conditions.
(f) Loose hypoid driven gear clamping
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
the trouble. However noises from the
engine, muffler, tire, exhaust gas, bear-
ing, 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 following four kinds of noises.
• Gear noise when driving: If noise
increases as vehicle speed increases it
may be due to insufficient gear oil, incor-
rect gear engagement, damaged gears,
etc.
• Gear noise when coasting: Damaged
gears due to maladjusted bearings and
incorrect shim adjustment
• Bearing noise when driving or when
coasting: Cracked, broken or damaged
bearings
• Noise which mainly occurs when turn-
ing: Unusual noise from differential side
gear, differential pinion, differential pin-
ion shaft, etc.
(a) Insufficient oil
Lubricate.
(b) Improper adjustment of hypoid driven
gear and drive pinion
Check tooth contact.
(c) Worn teeth of hypoid driven gear and
drive pinion
Replace as a set.
Readjust bearing preload.
(d) Loose roller bearing
Readjust hypoid driven gear to drive pin-
ion backlash and check tooth contact.
(e) Distorted hypoid driven gear or differ-
ential case
Replace.
(f) Worn washer and differential pinion
shaft
Replace.