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1977 PONTIAC SERVICE MANUAL
I
TORQUE CONVERTER DIAGNOSIS
CONDITION: Contaminated Oil
1.
If oil in the converter i s
discolored but does not contain
metal particles, the converter is not
damaged internally and need not be
replaced. Remove as much of the
discolored
oil
as
possible
by
draining through the hub.
2.
I f
oil
in the converter
contains
metal
particles,
the
converter i s damaged internally and
must be replaced. The oil may have
an "aluminum paint" appearance.
3.
If
the
cause
of
the
transmission failure was
due to
engine
coolant
(cooler
leak)
contamination, the converter must
be replaced.
4.
I f the pump gears or cover
show signs of damage or are broken,
the converter will contain metal
particles and must be replaced.
(NOTE: After failure that generates
sludge, metal particles or converter
replacement, it i s recommended that
the transmission be properly cleaned
and the cooler lines be flushed.
Refer to the Cooler and Cooler
Lines Flushing Procedure.)
CONDITION:
Stripped Converter
Bolt Holes
1.
lnspect for cause, such as
damaged bolt threads. To repair
stripped bolt holes, use heli-coils or
equivalent.
CONDITION: Noisy or Slips
(NOTE: Most converter noise occurs
under light throttle in "Drive" range
with brakes applied.)
1.
Check for loose or missing
flywheel
to
converter
bolts,
a
cracked
flywheel,
a
broken
converter pilot,
or other engine
parts that may be vibrating. I f any
of
these
conditions are found,
correct a s required.
2.
lnspect the converter for
damage to the roller bearing, thrust
races and roller clutch. The thrust
roller bearing and thrust races can
be checked by viewing them when
looking into the converter neck or
feeling through the opening to make
sure they are not cracked, broken
or mispositioned.
The stator roller clutch can be
checked by inserting a finger into
the splined inner race of the roller
clutch and trying to turn the race in
both directions. The inner race
should turn freely in the clockwise
direction, but not turn or be very
d i f f i c u l t
t o
turn
in
the
counterclockwise direction.
(NOTE: Do not use such items a s
the pump cover or stator shaft to
turn the race a s the results may be
misleading.)
The converter must be replaced
if the roller bearing, thrust races or
roller clutch are damaged.
3.
Inspect for excessive end
play. (Refer to Procedure) Repl ce
clearance exceeds .050".
I
the converter if turbine end pay
CONDITION: Vibration
1.
Isolate
the
cause
of
vibration
by
disconnecting other
engine driven parts one at a time. If
the converter i s determined to be
the cause of vibration, check for
loss of balance weights and replace
converter if weights are missing. If
weights are not missing, re-index
converter 120 degrees at a time to
cancel out engine and converter
unbalance conditions. Washers may
be
used
on
the
converter
to
flywheel bolts to isolate area of
unbalance.
CONDITION: Leak
1.
l nspect
converter
hub
surface for roughness, scoring or
wear that could damage seal or
bushing. I f roughness can be felt
with a fingernail, front seal could be
damaged. Repair the converter hub
with crocus cloth i f possible and
replace the front seal.
2.
lnspect the inside of the
bell housing. I f covered with oil, a
converter leak i s indicated and the
converter should be leak tested.
(Refer t o Procedure) Replace the
converter is leaks are found.
Fig. 7A1-6 Torque Convener Diagnosis Chart
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