Chevrolet CHEVY VAN G10 SERIES Service Manual page 250

CLUTCHES & TRANSM ISSIO NS 7-14
With the selector lever in the Park position, the parking
paw l should freely engage and prevent the vehicle from rolling.
The p o inter on the ind icator q u adrant should line up properly
w ith the range indicators in all ranges.
O IL LEAKS
Before attem ptin g to correct an oil leak, the actual source
o f the leak m ust be determ ined. In m any cases the source o f
the leak can be deceiving due to "wind flow " around the
engine and transm ission.
The suspected area should be wiped clean o f all oil before
inspecting for the source o f the leak. Red dye is used in the
transm ission oil at the assembly plant and will indicate if the
oil leak is from the transm ission.
The use o f a "black lig h t" to identify the oil at the source
o f leak is also helpful. Com paring the oil from the leak to th at
on the engine or transm ission dip stick (w hen viewed by black
light) will determ ine the source o f the leak.
Oil leaks around the engine and transm ission are generally
carried tow ard the rear o f the car by the air stream . For
exam ple, a transm ission " oil filler tube to case leak" will
som etim es appear as a leak at the rear o f the transm ission. In
determ ining the source o f an oil leak it is m ost helpful to keep
the engine running.
POSSIBLE POINTS OF O IL LEAKS
1. TRANSMISSION O IL PAN LEAK
a. A ttaching bolts n o t correctly torqued.
b . Im properly installed or dam aged pan gasket.
c. Oil pan gasket m ounting face not flat.
2. R E A R EXTENSION LEAK
a. A ttaching bolts n o t correctly torqued.
b . Rear seal assem bly— dam aged or im properly in ­
stalled.
c. Gasket seal— (extension to case) damaged or im­
properly installed.
d. Porous casting.
3. CASE LEAK
a. Filler pipe " 0 " ring seal damaged or missing; mis-
position o f filler pipe bracket to engine—" loading"
0
one side of " " ring.
b . M odulator asssem by " O " ring seal-dam ages or im ­
properly installed.
c. G overnor cover, and " 0 " ring seal— dam aged, loose;
case face leak.
d. Speedo gear- " 0 " ring damaged.
e. M anual shaft seal— dam aged, im properly installed.
f. Line pressure tap plug— stripped, shy sealer com ­
pound.
g. Parking pawl shaft cup plug— dam aged, im properly
installed.
h. V ent pipe (refer to Item 5).
i. Porous case.
4. FRO N T END LEAK
a. F ront seal— dam aged
nicks, etc., also for pum p bushing moved forw ard).
b. Pum p attaching bolts and seals— dam aged, missing,
bolts loose.
(check converter neck for
c. C o n v erter-leak in weld.
d. Pum p " 0 " ring seal— dam aged. (Also check pum p
groove and case bore.)
e. Porous casting (pum p or case).
5. OIL COMES OUT VENT PIPE
a. Transmission over-filled.
b. Water in oil.
c. Pum p to case gasket m ispositioned.
d. Foreign material betw een pum p and case, or be­
tween pum p cover and body.
e. C a se-p o ro u s, pum p face im properly machined.
f. P u m p -s h y o f stock on m ounting faces, porous
casting.
CASE POROSITY—REPAIR
Transmission leaks caused by alum inum case porosity have
been successfully repaired w ith the transmission in the vehicle
by using the following procedure.
1. Road test and bring the transm ission to operating tem per­
ature.
2. Raise the car and. w ith the engine running, locate the
source of the leak. Check for leaks in all operating
positions.
N O T E : The use of a m irror will be helpful in
finding leaks.
3. Shut o ff engine and thoroughly clean area witli a solvent
and air dry.
4. Using the instruction o f the m anufacturer, m ix a su f­
ficient am ount o f epoxy cem ent, part
make the repair.
5. While the transm ission is still h o t, apply the epoxy to the
area, making certain that the area is fully covered.
Fig. 3 —Pressure Tap Locations
?1360016. to
t
C H E V Y V A N SHOP M A N U A L