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7A2-8
1977 PONTIAC SERVICE MANUAL
c.
Intermediate
Band
burned
(see
BURNED
INTERMEDIATE BAND above).
Case
-
porosity between channels.
Slipping 2-3 Shift
(Install pressure gage)
Low Fluid Level
-
add fluid.
Low Oil Pressure
-
refer to Low Line Pressure above.
Direct Clutch:
a. Piston seals leak, damaged or missing.
b. Clutch plates burned (see BURNED CLUTCH
PLATES above).
c. Inspect for proper number and type of clutch plates.
Case
-
refer to case porosity repair.
Rough 1-2 Shift
(Install pressure gage)
High Fluid Pressure
-
refer to High Line Pressure
above.
1-2 Accumulator:
a. Oil rings damaged.
b. Piston stuck.
c. Broken or improper spring.
d. Bore damaged.
Case:
a. Check for correct number and location of check balls.
b. Porosity between channels.
Intermediate Band:
a. Improper adjustment.
b. Improper or broken servo spring.
Rough 2-3 Shift
Low and Reverse Clutch
-
piston inner seal damaged
or missing.
No Part Throttle Downshift
(Install pressure gage)
Fluid Pressure
-
vacuum modulator assembly,
modulator valve or pressure regulator valve train (other
malfunctions may also be noticed).
Detent Valve and Linkage
-
sticks, disconnected or
broken.
2-3 shift valve
-
stuck.
No Detent (Wide Open Throttle) Downshift
Detent cable or retainer not adjusted properly.
Detent cable disconnected at transmission or throttle
linkage.
Valve Body:
a. Detent valve sticks.
b. Detent regulator valve sticks.
c. Incorrect spacer plate or gasket.
High or Low Shift Points
(Install pressure gage)
Fluid Pressure:
a. Engine Vacuum
-
check at transmission end of
modulator pipe.
b. Check vacuum line connections at engine and
transmission.
c. Vacuum modulator assembly and valve and pressure
regulator valve train.
Governor:
a. Valve sticking.
b. Feed holes restricted or leaking.
(Install pressure gage)
High Fluid Pressure
-
above
2-3 Accumulator:
a. Oil ring damaged.
b. Piston stuck.
Detent Valve and Linkage
-
stuck open (will cause high
shift points).
refer to High Line Pressure
Control Valve Assembly:
a. 1-2 shift valve train sticking.
b. 2-3 shift valve train sticking.
Case
-
refer to case porosity repair.
c. Broken or missing spring.
d. Piston bore damaged.
No Engine Braking in L2 Range
(Install pressure gage)
Low Fluid Pressure
-
pressure regulator and/or boost
valve stuck.
Intermediate Servo:
a. Servo oil rings or bores leaking or damaged.
b. Servo piston stuck or cocked.
Intermediate Band
-
intermediate band broken or
burned (look for cause), not engaged on servo pin or improper
adjustment.
Won't Hold in Park
Manual Linkage
-
misadjusted (correct alignment in
manual lever shift quadrant is essential).
Internal Linkage:
a. Inner lever and actuating rod assembly
-
defective or
improperly installed.
b. Parking pawl
-
broken or inoperative.
c.
Parking lock bracket loose, burred or rough edges or
incorrectly installed.
d. Parking pawl disengaging spring missing, broken or
incorrectly hooked.
TRANSMISSION NOISY
No Engine Braking on
L1
Range
CA UT I0 N
:
Before checking transmission, make
certah that noise is not coming fiom water pump,
(Install pressure gage)
generator, power steering, etc. These components
Low Fluid Pressure
-
pressure regulator and/or boost
can be isolated by removing proper belt and
valves stuck.
running engine not more than two minutes at one
Manual Low Control Valve Assembly
-
stuck.
time.
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