Possible Points Of Oil Leaks; Transmission Oil Pan Leak; Rear Extension Leak; Case Leak - Pontiac Grand Prix Service Manual

TURBO HYDRA-MATIC-M-40
7E-61
the vacuum modulator tube connected for normal
modulator operation, the transmission pressures should
check approximately as shown in Fig. 7E-184.
NOTE:
Pressures are not signifcantly affected by
altitude or barometric pressure when the vacuum
modulator tube is connected.
OIL LEAKS
Before attempting to correct an oil leak, the actual
source of the leak must be determined. In many cases,
the source of the leak can be deceiving due to wind
flow around the engine and transmission.
The suspected area should be wiped clean of all oil
before inspecting for the source of the leak. Red dye is
used in the transmission oil at the assembly plant and
will indicate if the oil leak is from the transmission.
The use of a black light to identify the oil at the source
of leak is also helpful. Comparing the oil from the leak
to that on the engine or transmission dipstick (when
viewed by black Light) will determine the source of the
leak.
Oil leaks around the engine and transmission are
generally carried toward the rear of the car by the air
stream. For example, a transmission oil filler tube to
case leak will sometimes appear as a leak at the rear of
the transmission. In determining the source of an oil
leak, it is most helpful to keep the engine running.
POSSIBLE POINTS OF OIL LEAKS
b. Modulator O-ring seal-damaged or improperly
installed.
c. Governor cover, gasket and bolts-damaged, loose;
case face leak.
d. Speedo gear O-ring damaged.
e. Manual shaft seal-damaged, improperly installed.
f. Line pressure tap plug-stripped, shy sealer com-
pound.
g. Parking pawl shaft cup plug-damaged, improperly
installed.
h. Vent pipe (refer to item 5).
i. Porous case.*
4. FRONT END LEAK
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 PIPE
a. Transmission over-filled.
1. TRANSMISSION OIL PAN LEAK
b. Water in oil.
a. Attaching bolts not correctly torqued.
b. Improperly installed or damaged pan gasket.
c. Oil pan gasket mounting face not flat.
2. REAR EXTENSION LEAK
a. Attaching bolts not correctly torqued.
b. Rear seal assembly
-
damaged or imporperly
installed.
c. Extension to case gasket-damaged or improperly
installed.
c. Pump to case gasket mispositioned.
d. Foreign material between pump and case, or
between pump cover and body.
e. Case-porous, pump face improperly machined.*
f. Pump-shy of stock on mounting faces, porous
casting, breather hole plugged in pump cover.
g. Incorrect dipstick.
h. Cut O-ring or grommet on strainer.
d. Porous casting.*
*CASE POROSITY REPAIR
3. CASE LEAK
Turbo Hydra-Matic transmission leaks caused by case
a. Filler pipe O-ring seal-damaged or missing; misposi-
porosity. (not cracks) may be repaired w[th the
tion of filler pipe bracket to engine-loading one side of
transmission
in
the car by using epoxy cement and
O-ring. following this recommended procedure: