Jeep Cherokee 1999 Electronic Service Manual page 1403

21 - 80 TRANSMISSION AND TRANSFER CASE
DI AGN OSI S AN D T EST I N G (Cont inue d)
Th is pr ocess of elim in a t ion ca n be u sed t o iden t ify
a slippin g u n it a n d ch eck oper a t ion . P r oper u se of
t h e Clu t ch a n d Ba n d Applica t ion Ch a r t is t h e key.
Alt h ou gh r oa d t est a n a lysis will h elp det er m in e t h e
slippin g u n it , t h e a ct u a l ca u se of a m a lfu n ct ion u su -
a lly ca n n ot be det er m in ed u n t il h ydr a u lic a n d a ir
pr essu r e t est s a r e per for m ed. P r a ct ica lly a n y con di-
t ion ca n be ca u sed by lea kin g h ydr a u lic cir cu it s or
st ickin g va lves.
Un less a m a lfu n ct ion is obviou s, su ch a s n o dr ive
in D r a n ge fir st gea r, do n ot disa ssem ble t h e t r a n s-
m ission . P er for m t h e h ydr a u lic a n d a ir pr essu r e t est s
t o h elp det er m in e t h e pr oba ble ca u se.
HYDRAULIC PRESSURE TEST
H ydr a u lic t est pr essu r es r a n ge fr om a low of on e
psi (6.895 kP a ) gover n or pr essu r e, t o 300 psi (2068
kP a ) a t t h e r ea r ser vo pr essu r e por t in r ever se.
An a ccu r a t e t a ch om et er a n d t wo t est ga u ges a r e
r equ ir ed for t h e pr essu r e t est . Test Ga u ge C-3292
h a s a 100 psi r a n ge a n d is u sed a t t h e a ccu m u la t or,
gover n or, a n d fr on t ser vo pr essu r e por t s. Test Ga u ge
C-3293-SP h a s a 300 psi r a n ge a n d is u sed a t t h e
r ea r ser vo por t a n d over dr ive t est por t s wh er e pr es-
su r es a r e h igh er. In ca ses wh er e t wo t est ga u ges a r e
r equ ir ed, t h e 300 psi ga u ge ca n be u sed a t a n y of t h e
ot h er t est por t s.
Pressure Test Port Locations
P r essu r e t est por t s loca t ion s a r e pr ovided a t t h e
a ccu m u la t or, fr on t ser vo, a n d r ea r ser vo, gover n or
pa ssa ge, a n d over dr ive clu t ch pr essu r e pa ssa ge (F ig.
6), (F ig. 7) a n d (F ig. 8).
Lin e pr essu r e is ch ecked a t t h e a ccu m u la t or por t
on t h e r igh t side of t h e ca se. Th e fr on t ser vo pr essu r e
por t is a t t h e r igh t side of t h e ca se ju st beh in d t h e
filler t u be open in g.
Fig. 6 Pressure Test Ports At Side Of Case
Con n ect a t a ch om et er t o t h e en gin e. P osit ion t h e
t a ch om et er so it ca n be obser ved fr om u n der t h e
veh icle. Ra ise t h e veh icle on a h oist t h a t will a llow
t h e wh eels t o r ot a t e fr eely.
Fig. 7 Pressure Test Ports At Rear Of Case—2WD
Fig. 8 Pressure Test Ports At Rear Of Case—4WD
PRESSURE TEST PROCEDURE
Test One - Transmission In 1 Range
Th is t est ch ecks pu m p ou t pu t , pr essu r e r egu la t ion ,
a n d con dit ion of t h e r ea r clu t ch a n d ser vo cir cu it .
Test Ga u ges C-3292 a n d C-3293-SP a r e r equ ir ed for
t h is t est . Ga u ge C-3292 h a s a 100 psi r a n ge. Ga u ge
C-3293-SP h a s a 300 psi r a n ge.
(1) Con n ect 100 psi Ga u ge C-3292 t o a ccu m u la t or
por t .
(2) Con n ect 300 psi Ga u ge C-3293-SP t o r ea r ser vo
por t (F ig. 6) a n d (F ig. 7).
(3) Discon n ect t h r ot t le a n d gea r sh ift r ods fr om
m a n u a l a n d t h r ot t le lever s.
(4) St a r t a n d r u n en gin e a t 1000 r pm .
(5) Move sh ift lever (on m a n u a l lever sh a ft ) a ll t h e
wa y for wa r d in t o 1 r a n ge.
(6) Move t r a n sm ission t h r ot t le lever fr om fu ll for-
wa r d t o fu ll r ea r wa r d posit ion a n d n ot e pr essu r es on
bot h ga u ges.
(7) Lin e pr essu r e a t a ccu m u la t or por t sh ou ld be
54-60 psi (372-414 kP a ) wit h t h r ot t le lever for wa r d
a n d gr a du a lly in cr ea se t o 90-96 psi (621-662 kP a ) a s
lever is m oved r ea r wa r d.
(8) Rea r ser vo pr essu r e sh ou ld be sa m e a s lin e
pr essu r e wit h in 3 psi (20.68 kP a ).
Test Two - Transmission In 2 Range
Th is t est ch ecks pu m p ou t pu t a n d pr essu r e r egu la -
t ion . Use 100 psi Test Ga u ge C-3292 for t h is t est .
(1) Con n ect t est ga u ge t o a ccu m u la t or pr essu r e
por t (F ig. 6) a n d (F ig. 7).
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