GMC 1976 ZEO 6083 Maintenance Manual page 459

When installing a new pump oil seal, make cer-
tain that bore is free from foreign material and that
garter spring on seal is correctly positioned . Check
finish of converter neck and bearing surface in pump
body .
2. Pump assembly-to-case O-ring damaged. Also
check case bore .
3. Converter - Inspect converter for indications
of leakage.
4. Vent fitting damaged.
5. Pump attaching bolts loose.
6. Porous casting (pump or case).
7. Pump drainback hole not open .
COVER AND PLATE ASSEMBLY
SPROCKET HOUSING LEAK
1 . Attaching bolts not correctly torqued.
2. Housing to case gasket improperly installed or
damaged.
3 . Housing to case gasket face not flat .
FINAL DRIVE TO TRANSMISSION LEAK
1 . Attaching bolts not correctly torqued.
2 . Final drive to transmission gasket improperly
installed or damaged.
3 . Mounting surfaces not flat .
TRANSMISSION CASE
1 . Speedometer driven gear housing retainer at-
taching screw loose. Tighten to 18 foot-pounds.
2. Speedometer
driven gear housing O-ring or lip
seal damaged. Leak at speedo hole .
3 . Governor cover bale-type attaching retainer
not tight.
4. Damaged governor O-ring .
5 . Governor drainback in case not open .
6. Solenoid connector terminal O-ring damaged
or improperly installed.
7. Manual shaft O-ring damaged or improperly
installed.
chined .
8 . Vacuum modulator damaged.
12 . Bottom pan gasket damaged.
16 . Vent pipe .
a. Transmission over-filled .
b. Water in oil.
h. Hole in intake pipe.
TRANSMISSION 7- 11
9 . Vacuum modulator retainer screw loose.
Tighten to 18 foot-pounds.
10 . Vacuum modulator diaphragm damaged,
(not an external oil leak).
NOTE :
A ruptured diaphragm would allow
transmission oil to be drawn into intake mani-
fold and vacuum line . Usually the exhaust will
be excessively smoky due to transmission oil ad-
ded to the combustion . Oil level of transmission
will also be low.
11 . Modulator assembly O-ring seal damaged or
improperly installed.
13 . Bottom pan attaching screws loose. Tighten
to 12 foot-pounds.
14 . Line pressure plug not tight. Tighten to 10
foot-pounds. Also, plug stripped, shy sealer com-
pound.
15 . Porous or cracked casting. Case cracked at
pressure plug boss .
c. Pump to case gasket mispositioned .
d. Foreigh material between pump and case,
or between pump cover and body .
e. Case - Porous, pump face improperly ma-
f. Pump - Shy of stock, porous .
g. Filter O-ring damaged or improperly as-
sembled causing oil to foam .
i. Drainback hole in case plugged or re-
stricted . See Figure 6 for location .
OIL COOLER PIPE CONNECTIONS
1 . Outside oil cooler pipe connections improperly
installed or damaged. Also connectors in radiator
and transmission .