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7-37
PART
7-2
C4 AUTOMATIC TRANSMISSION
DIAGNOSIS AND TESTING
When diagnosing transmission
problems, first refer to the diagnosis
guide for detailed information on
the items that could be causing the
problem. The following preliminary
checks should be made in the order
given:
1. Check the fluid level. Check
the fluid for a burnt clutch plate
odor.
1. Check the engine idle speed
and dashpot adjustments.
3. Check the manual linkage
adjustment.
4. Check the accelerator pedal
height and downshift linkage.
S. Check the throttle linkage to
assure wide open throttle operation.
6. Check the engine for proper
operation.
TRANSMISSION FLUID
LEVEL CHECK
1. Make sure that the vehicle is
standing level. Then firmly apply
the parking brake.
2. Run the engine at normal idle
speed. If the transmission fluid is
cold, run the engine at fast idle
speed (about 1200 rpm) until the
ftuid reaches its normal operating
temperature. When the ftuid is
warm, slow the engine down to
normal idle speed.
3. Shift the selector lever through
all positions, and place the lever at
P. Do not turn off the engine during
the fluid level checks.
4. Clean all dirt from the trans-
mission fluid dipstick cap before
removing the dipstick from the
filler tube.
S. Pull the dipstick out of the
tube, wipe it clean, and push it all
the way back into the tube.
6. Pull the dipstick out of the
tube again, and check the fluid level.
If necessary, add enough fluid to
the transmission through the filler
tube to raise the fluid level to the
F (full) mark on the
dipstick.
Do
not overfill the traasmission.
FLUID AERATION CHECK
A fluid level that is too high will
cause the fluid to become aerated.
Aerated fluid will cause low control
pressure, and the aerated fluid may
be forced out the vent.
Check the transmission fluid level.
Low fluid level can affect the opera-
tion of the transmission, and may
indicate fluid leaks that could cause
transmission damage.
TRANSMISSION FLUID
LEAKAGE CHECKS
Check the speedometer cable con-
nection at the transmission. Leak-
age at the oil pan gasket often can
be
stopped by tightening the attach-
ing bolts to the proper torque. If
necessary, replace the gasket. Check
the fluid filler tube connection at
the transmission. If the filler tube
0-ring seal is leaking, replace the
seal.
The transmission fluid is water
cooled; check the fluid lines and fit-
tings between the transmission and
the cooler in the radiator tank for
looseness, wear, or damage. If leak-
age cannot
be
stopped by tightening
a fitting, replace the defective parts.
Check the engine coolant in the
radiator. If transmission ftuid is
present in the coolant, the cooler
in the radiator tank is probably
leaking.
The cooler can
be
further checked
for leaks by disconnecting the lines
at the cooler fittings and applying
5 psi air pressure to the
fittings.
The
radiator cap must be removed when
making this check to relieve the
pres~re
on the exterior side of the
cooler. If the cooler is leaking and
will not hold this pressure, the
radiator must
be
replaced.
The
cooler cannot be replaced separately.
If leakage is found at either the
throttle lever shaft or the manual
lever shaft, replace either or both
seals.
Inspect the pipe plug in the
case.
If the plug shows leakage, torque
the plug to specification. If tighten-
ing does not stop the leaks, replace
the plug.
When converter drain plugs leak,
remove the two drain plugs with a
six-point wrench. Coat the threads
with a sealing compound, and in-
stall the plugs. Torque the drain
plugs to specification. Fluid leakage
from the converter housing may be
caused by engine oil leaking past
the rear main bearing or from oil
gallery plugs.
Be
sure to determine
the exact cause of the leak.
Oil-soluble aniline or fluorescent
dyes premixed at the ratio of
l
teaspoon of dye powder to
t
pint
of transmission fluid have proved
helpful in locating the source of
the fluid
leakage.
Such dyes may
be
used to determine whether an
engine oil or transmission fluid leak
is present, or if the fluid in the oil
cooler leaks into the engine coolant
system. A black light, however,
must be used with the fluorescent
dye solution.
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