Pontiac tempest 1968 Service Manual page 497

7E-62
1968 P O N T I A C SERVICE M A N U A L
f . Line pressure tap plug—stripped, shy sealer
compound.
g. Parking pawl shaft cup plug—damaged, im­
properly installed.
h. Vent pipe (refer to item 5).
I . Porous case.
4. FRONT END L E A K
a. Front seal - damaged (check converter neck
for nicks, etc., also for pump bushing moved
forward); garter spring missing from pump to
converter hub seal.
b. Pump attaching bolts and seals—damaged,
missing, bolts loose.
c. Converter—leak in weld.
d. Pump O-ring seal—damaged. Also check
pump groove and case bore.
e. Porous casting (pump or case).
5. OIL COMES OUT VENT P I P E
a. Transmission over-filled.
b. Water in oil.
c. Pump to case gasket mispositioned.
d. Foreign material between pump and case,
or between pump cover and body.
e. Case—porous, pump face i m p r o p e r l y
machined.
f. Pump— shy of stock on mounting faces, por­
ous casting, breather hole plugged in pump cover.
g. Incorrect dipstick.
h. Cut O-ring or grommet on strainer.
TURBO HYDRA-MATIC TRANSMISSION-
VACUUM MODULATOR CHECK
1. Vacuum Diaphragm Leak Check
Insert a pipe cleaner into the vacuum connector
pipe as far as possible and check for the presence
of transmission oil. If oil is found, replace the
modulator.
NOTE: Gasoline or water vapor may settle in the
vacuum side of the modulator. If this is found with­
out the presence of oil, the modulator should not
be changed.
2. Atmospheric Leak Check
Apply a liberal coating of soap bubble solution
(obtainable at a 5f-10£ store) to the vacuum con­
nector pipe seam, the crimped upper to lower hous­
ing seam and the threaded screw seal (Fig. 7E-174).
Using a short piece of rubber tubing, apply air pres­
sure to the vacuum pipe by blowing into the tube and
observe for leak bubbles. If bubbles appear, replace
the modulator.
NOTE: Do not use any method other than human
lung power for applying air pressure, as pressures
over 6 psi may damage the modulator.
3. Bellows Comparison Check
Using a comparison gauge (Fig. 7E-175), compare
the load of a known good Hydra-Matic modulator
with the assembly in question:
a. Install the modulator that is known to be
acceptable on either end of the gauge.
b. Install the modulator in question on the op­
posite end of the gauge.
c. Holding the modulators in a horizontal po­
sition, bring them together under pressure until
either modulator sleeve end just touches the line in
the center of the gauge. The tap between the op­
posite modulator sleeve end and the gauge line
i — T H R E A D E D S C R E W S E A L
S U P P E R T O L O W E R
H O U S I N G S E A M
- V A C U U M C O N N E C T O R
S E A M
• E N D S T O B E S Q U A R E
W I T H I N 1 / 6 4 "
- 1 / 2 ' ^
- S C R I B E D L I N E
32
. 3 " R O U N D O R
8 F L A T S T O C K -
F i g . 7 E - 1 7 4 Cross Section of Vacuum Modulator
F i g . 7 E - 1 7 5 Comparison G a u g e