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AUTOMATIC TRANSMISSION
21 - 113
Fig. 3 A-518 Valve
TORQUE
CONVERTER
APPLICATION
Lockup a n d nonlockup torque converters are used.
A lockup converter is used w i t h t h e A-500. A-518
models are equipped w i t h a nonlockup converter.
RECOMMENDED
FLUID
Recommended fluid for use i n A-500/518 overdrive
transmissions is Mopar A T F Plus, Type 7176. Mopar
Dexron II™ can be used i f A T F Plus is not available.
Mercon™ fluid is not recommended for use i n A -
500/518 transmissions for r e f i l l i n g after
filter/fluid
changes, or after overhaul. I t can only be used for
topping off t h e fluid level d u r i n g periodic checks.
SERVICE DIAGNOSIS
GENERAL
DIAGNOSIS
INFORMATION
A-500/518 automatic transmission problems can be
a result of: poor engine performance; incorrect
fluid
level; incorrect linkage adjustment; electronic compo-
nent shorts-grounds-opens; band or h y d r a u l i c control
pressure
adjustments; h y d r a u l i c system
malfunc-
tions; or mechanical component malfunctions.
Begin diagnosis by checking the easily accessible
items such as fluid level and condition, l i n k a g e ad-
j u s t m e n t s a n d overdrive fuse, solenoid and w i r e con-
d i t i o n . A road test w i l l determine i f f u r t h e r diagnosis
>dy Lower Housing
is necessary. The overdrive u n i t should not be r e -
moved unless diagnosis reveals a n actual overdrive
fault.
ROAD
TESTING
Before road testing, be sure fluid level and linkage
adjustments are correct and t h a t t h e overdrive cir-
cuit fuse and electrical connections are O K .
Observe engine performance d u r i n g the road test.
A poorly t u n e d engine w i l l not allow a n accurate
analysis o f transmission operation.
Operate the transmission i n a l l gear ranges. Check
for slippage and shift variations. Note whether t h e
shifts are h a r s h , spongy, delayed, early, or i f down-
shifts are sensitive.
W a t c h closely for slippage or engine flare w h i c h
u s u a l l y indicates clutch, band or o v e r r u n n i n g c l u t c h
problems. I f the condition is advanced, a n overhaul
m a y be necessary to restore n o r m a l operation.
A s l i p p i n g clutch or band can often be determined
by comparing w h i c h i n t e r n a l u n i t s are applied i n the
various gear ranges. The clutch and band application
chart (Fig. 1) provides a basis for analyzing road test
results.
For example: I f slippage occurs d u r i n g the 3-4 shift
or i n f o u r t h gear, t h e overdrive clutch is slipping.
S i m i l a r l y , i f the direct clutch were t o f a i l , the t r a n s -
mission w o u l d lose reverse gear and overrun b r a k i n g
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