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AUTOMATIC TRANSMISSION
21 - 51
I f the transmission slips i n t h i r d gear, either t h e
front clutch or t h e rear clutch i s slipping. B y select-
i n g another gear w h i c h does n o t use one of these
units, t h e s l i p p i n g c l u t c h can be determined. For ex-
ample, i f t h e transmission also slips i n Reverse, the
front clutch is s l i p p i n g . I f the transmission does n o t
slip i n Reverse, t h e r e a r clutch is slipping.
This process o f e l i m i n a t i o n can be used to deter-
mine t h e s l i p p i n g u n i t a n d check operation. Proper
use of the C l u t c h a n d B a n d A p p l i c a t i o n C h a r t is t h e
key.
A l t h o u g h road test analysis w i l l help determine
the s l i p p i n g u n i t , t h e actual cause of a malfunction
usually cannot be determined u n t i l h y d r a u l i c and a i r
pressure tests are performed. Practically a n y condi-
t i o n can be caused b y l e a k i n g hydraulic circuits or
sticking valves.
U n l e s s t h e c o n d i t i o n i s o b v i o u s , s u c h as n o
d r i v e i n D r a n g e ,
first
g e a r o n l y , t h e t r a n s m i s -
s i o n s h o u l d n o t b e d i s a s s e m b l e d u n t i l h y d r a u l i c
a n d a i r p r e s s u r e t e s t s h a v e b e e n p e r f o r m e d .
HYDRAULIC PRESSURE TEST
H y d r a u l i c test pressures range f r o m a l o w of one
psi (6.895 k P a ) governor pressure, to 300 p s i (2068
kPa) a t t h e rear servo pressure port i n reverse. Use
100 psi test gauge C-3292 to check pressure a t t h e
accumulator, f r o n t servo, governor a n d fluid cooler
line. Use 300 p s i gauge C-3293 t o check pressure a t
the rear servo.
PRESSURE
TEST PORT
LOCATIONS
There are pressure test ports a t t h e accumulator,
front servo, rear servo and governor.
Line pressure i s checked a t t h e accumulator port
on the r i g h t side o f t h e case (Fig. 2). The front servo
release pressure p o r t is a t t h e r i g h t side o f the case
j u s t behind t h e filler tube opening (Fig. 2).
The rear servo pressure port is a t t h e r i g h t rear of
the transmission case (Fig. 3). The governor pressure
port is a t t h e left side of case a t t h e transmission
rear (Fig. 3).
PRESSURE
TEST
PROCEDURE
Connect a tachometer to t h e engine. Position t h e
tachometer so i t can be observed f r o m under t h e ve-
hicle. Raise t h e vehicle on a hoist t h a t w i l l allow the
wheels to rotate
freely.
Test One-Transmission In 1 Range
T h i s t e s t c h e c k s p u m p o u t p u t , p r e s s u r e r e g u l a -
t i o n , a n d c o n d i t i o n o f t h e r e a r c l u t c h a n d r e a r
s e r v o c i r c u i t s .
A P P L Y
P O R T
F R O N T
S E R V O
R E L E A S E
P O R T
R H 2 5 0
Fig. 2 Pressure Test Ports At Side Of Transmission
L U B R I C A T I O N
P R E S S U R E
P O R T
( C O O L E R
R E T U R N
G O V E R N O R
Fig. 3 Pressure Test Ports At Rear Of Transmission
(1) Connect test gauges to t h e l i n e pressure a n d
rear servo ports (Figs. 2, 3). B e s u r e t h e 300 p s i
g a u g e i s c o n n e c t e d t o t h e r e a r s e r v o p o r t .
(2) Disconnect the t h r o t t l e and gearshift rods a t t h e
transmission.
(3) S t a r t a n d r u n t h e engine a t 1000 r p m .
(4) Move t h e valve body selector lever a l l t h e w a y
f o r w a r d i n t o 1 range.
(5) Read pressures on both gauges as t h e transmis-
sion t h r o t t l e lever is i s moved f r o m f u l l forward t o
f u l l r e a r w a r d position.
(6) L i n e pressure should be 54-60 psi (372-414 kPa)
w i t h t h r o t t l e lever f o r w a r d and g r a d u a l l y increase t o
90-96 p s i (621-662 kPa) as lever is moved r e a r w a r d .
(7) Rear servo pressure should be t h e same as l i n e
pressure w i t h i n 3 psi.
Test Two-Transmission In 2 Range
T h i s t e s t c h e c k s p u m p o u t p u t a n d p r e s s u r e
r e g u l a t i o n .
(1) Connect a test gauge to t h e l i n e pressure port
(Fig. 2).
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