Pontiac FIREBIRD 1972 Service Manual page 991

7F-4
1972 PONTIAC SERVICE MANUAL
1. Stuck low and drive valve.
2. Defective governor.
3. Stuck or maladjusted throttle valve.
4. Maladjusted manual valve lever.
NO DOWNSHIFT
1. Low TV pressure.
2. High governor pressure.
3. Sticking low and drive shift plug.
4. Sticking low and drive shift valve.
HARSH UPSHIFT
1. Improper carburetor-to-transmission TV rod adjust-
ment.
2.
Improper band adjustment.
3. Broken or disconnected vacuum modulator line.
4. Leaking vacuum modulator diaphragm.
5. Sticking vacuum modulator valve.
6. Sticking booster valve in valve body.
HARSH CLOSED THROTTLE (COAST)
DOWNSHIFT
1. High engine idle speed.
2. Improper band adjustment.
3. Malfunction of downshift timing valve.
4. High mainline pressure, probably due to:
a. Vacuum modulator line broken or disconnected.
b. Modulator diaphragm ruptured.
c. Sticking vacuum modulator valve, pressure
regulator valve or booster valve.
NO DRIVE IN REVERSE
1. Improper manual valve lever adjustment.
2. Stuck reverse clutch piston.
3. Worn out reverse clutch plates.
4. Reverse clutch leaking excessively.
5. Blocked reverse clutch apply orifice.
IMPROPER SHIFT POINTS
1. Improper carburetor-to-transmission linkage adjust-
ment.
2.
Improper throttle valve (TV) adjustment.
3. Defective governor.
BURNED CLUTCH PLATES
1. Band adjusting screw backed off more than specified.
2.. Improper order of clutch plate assembly.
3. Extended operation with low oil level.
4. Stuck relief ball in clutch drum.
5. Abnormally high speed upshift, probably due to:
a. Improper governor action.
b. Transmission operated at high speed in manual
"low".
CAR CREEPS EXCESSIVELY IN DRIVE
RANGE
Idle speed set too high.
CAR CREEPS IN NEUTRAL RANGE
1. Improper manual valve lever adjustment.
2. High clutch or low band not released.
OIL LEAKS
1. Transmission case and extension housing: