Subaru IMPREZA 2002 Service Manual page 309

r
Symptom
1 . Broken differential (case, gear, bear-
ng, etc.)
VOTE:
4bnormal noise will develop and finally it
Mill become impossible to continue to run
h e to broken pieces obstructing the gear
,evolution.
I
GENERAL DIAGNOSTIC
MANUAL TRANSMISSION AND DIFFERENTIAL
Possible cause
(a) Insufficient or improper oil
(b)
use
of vehicle under Severe con&
tions such as
load and
improper use of clutch
2. DIFFERENTIAL
2. Differential and hypoid gear noises
b u b l e s of the differential and hYPoid
p a r always appear as nOiSe problems.
(a) Insufficient oil
(b) Improper adjustment of hypoid driven
sear
and drive Dinion
(c) Improper adjustment of taper roller
bearing
(d) Improper adjustment of drive pinion
and hvlsoid driven aear
(e) Excessive backlash due to worn dif-
ferential side gear, washer or differential
pinion vehicle under severe operating
conditions
(f) Loose hypoid driven gear clamping
I
bolts
jifferential noise. Pay special attention to
:he hypoid gear noise because it is easily
:onfused with other gear noises. There
we the following four kinds of noises.
1
Gear noise when driving: If noise
ncreases as vehicle speed increases it
nay be due to insufficient gear oil, incor-
O e c t gear engagement, damaged gears,
2tc.
1
Gear noise when coasting: Damaged
jears due to maladjusted bearings and
ncorrect shim adjustment
1
Bearing noise when driving or when
:oasting: Cracked, broken or damaged
3earings
1
Noise which mainly occurs when turn-
ng: Unusual noise from differential side
jear, differential pinion, differential pinion
;haft. etc.
I
vi
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iypuiu
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rherefore noise is the first indication of
:he trouble. However noises from the
mgine, muffler, tire, exhaust gas, bear-
ng, body, etc. are easily mistaken for the
,e roller bearing
(e) Distorted hypoid driven gear or differ-
ential case
(f) Worn washer and differential pinion
shaft
Remedy
3isassemble differential and replace bro-
ten components and at the same time
:heck other components for any trouble,
3nd replace if necessary.
Readjust bearing preload and backlash
m d face contact of gears.
4djust.
4djust.
4dd recommended oil to specified level.
Do not use vehicle under severe operat-
ng conditions.
Tighten.
-ubricate.
:heck tooth contact.
Replace as a set.
Readjust bearing preload.
Readjust hypoid driven gear to drive pin-
on backlash and check tooth contact.
Replace.
Replace.
MT-85