Copyright by Goodheart-Willcox Co., Inc.
Chapter 15 Transmission and Transaxle In-Vehicle Service 381
Manual shaft seal
Figure 15-28. Manual shaft seals can be carefully pried from
the case with a screwdriver. Special tools are available to
remove the seal without removing the manual valve shaft.
(General Motors)
O-ring
Electrical
connector
Figure 15-29. An O-ring is commonly used to seal electrical
connectors to the case. O-rings can be removed by prying them
off with a pointed tool or by carefully pulling them from their
grooves. Carefully clean the groove before installing the new
O-rings. (General Motors)
Seal Replacement
Metal clad seals are used whenever a rotating part must
be sealed in relation to a stationary part. Seals such as the
manual shaft seal can be pried out of the case once the shaft
has been removed, Figure 15-28. Clean the area where the
seal was installed. Then install a new seal into the case. Most
seals can be gently tapped into place using a socket and
hammer. If necessary, use sealer on the outer part of the seal
housing. Once the seal is in place, lightly lubricate the seal
lip. Then reinstall the shaft and check for leaks.
O-Ring Replacement
Many case electrical connectors have O-rings that seal
the connector to the case, as shown in Figure 15-29.
To change the O-ring, remove the external electrical con-
nector and depress the internal locking tabs to remove the
case connector. In many cases, the oil pan must be
removed to depress the locking tabs. After depressing the
tabs, pull the case connector from the case. Remove the
O-ring and clean the sealing area. Lightly lubricate the new
O-ring and install it on the case connector. Then reinstall
the case connector by pressing it into the case. Make sure
the locking tabs engage to hold the connector in place.
Then reinstall other parts as necessary, refill the transmis-
sion or transaxle, and check for leaks. Road test the vehicle
if necessary.
Gasket Replacement
Gaskets are commonly used on transmission/transaxle
oil pans, side covers, timing gear and differential covers,
tailshaft housings, governor covers, and other places where
two flat surfaces must be sealed. To replace a gasket,
remove the pan or cover by removing the attaching bolts.
Have a drain pan handy in case of oil leakage. Once the
parts are separated, remove all old gasket material from the
pan/cover and the case. Be careful not to scratch the sealing
surfaces. Some technicians use solvents to dissolve the gas-
ket material. Thoroughly clean the pan or cover and case to
remove all particles of gasket material. Check the pan or
cover for warping and damage at the sealing area. If the pan
or cover cannot be straightened, it should be replaced.
Install the new gasket using the proper sealant. If the
pan/cover uses a gasket-making compound, apply it accord-
ing to manufacturer’s directions. In most cases, the sealant
is applied to only one of the mating surfaces. Then reas-
semble the parts, carefully tightening the attaching fasten-
ers. Begin by slightly tightening the fasteners. Alternately
tighten the fasteners on opposite sides of the part. If you are
installing a part with many fasteners, such as an oil pan,
begin tightening the center fasteners, slowly working out-
ward. See Figure 15-30. Repeat the tightening sequence,
gradually increasing the torque. Whenever possible, use a
torque wrench to make the final tightening sequence. Then
refill the transmission/transaxle if necessary and road test.
Finally, recheck for leaks.
Adding an Auxiliary Oil Cooler
You may be asked to install an auxiliary, or external,
oil cooler to a vehicle that will be used for towing or other
severe service. Start by determining what size cooler is
needed. For instance, towing a small boat would require a
smaller cooler than towing a large travel trailer. Cooler
manufacturers provide charts detailing what size cooler is
appropriate for different situations. After obtaining the
cooler, make sure that it is the correct size and that all hoses
and attaching hardware are included.
Next, determine the best place to install the cooler.
Coolers should be installed ahead of the radiator and air