Chevrolet 10 Series 1970 Service Manual page 473

fr o m ro llin g . The pointer
should line up p ro p e rly with the range indicators in all
ranges.
OIL LEAKS
B e fo re attem pting to c o r r e c t an o il leak, the actual
sou rce of the leak must be determ ined.
the sou rce o f the leak can be d eceivin g due to "w in d
flo w " around the engine and transm ission.
The suspected a rea should be wiped clean of all o il b e­
fo r e inspecting fo r the source of the leak.
used in the tran sm ission oil at the assem bly plant and
w ill indicate if the o il leak is fro m the transm ission.
The use of a "b la c k light"
source of leak is also helpful.
the leak to that on the engine or tran sm ission dip stick
(when view ed by black light) w ill determ ine the source
of the leak.
O il leaks around the engine and transm ission are gen­
e r a lly c a rr ie d toward the r e a r of the car by the a ir
stream . F o r exam ple, a transm ission
case leak" w ill som etim es appear as a leak at the r e a r
of the transm ission. In determ ining the source of an oil
leak it is most helpful to keep the engine running.
POSSIBLE POINTS OF OIL LEAKS
1. TRANSM ISSION O IL P A N L E A K
a. Attaching bolts not c o r r e c tly torqued.
b. Im p ro p erly in stalled
c. O il pan gasket mounting face not flat.
2. R E AR E XTEN SIO N L E A K
a. Attaching bolts not c o r r e c tly torqued.
b. R ea r seal assem bly -
installed.
c. Gasket sea l - (extension to case) damaged or
im p ro p erly installed.
d. Porou s casting.
3. CASE L E A K
a. F ille r pipe " O " ring seal damaged or m issing;
m isposition o f f i l l e r
" load in g'' one side of " O " ring.
b. M odulator assem bly " O "
im p ro p e rly installed.
c. G overn or c over, and " O "
loose; case face leak.
d. Speedo gea r - " O " rin g damaged.
e. Manual shaft seal-dam aged, im p ro p e rly installed.
f . Line p ressu re tap plug -
compound.
g. P ark in g pawl shaft cup plug - damaged, im prop­
e r ly installed.
h. Vent pipe (r e fe r to Item 5).
i . Porou s case.
4. F R O N T END L E A K
a. Front seal - damaged (check con verter neck fo r
nicks, e tc .,a ls o fo r pump bushing moved forw ard ).
b. Pump attaching bolts and seals - damaged, m is s ­
ing, bolts loose.
c. C on verter - leak in weld.
d. Pump " O " rin g sea l -
pump gro o ve and case b o re .)
e. Porou s casting (pump or case).
5. O IL COMES OUT V E N T P IP E
a. T ra n sm ission o v e r -fille d .
on the indicator quadrant
In many cases,
Red dye is
to identify the o il at the
Com paring the oil from
" o i l f i l l e r tube to
o r damaged pan gasket.
damaged o r im p rop erly
pipe bracket to engine -
ring seal - damaged or
rin g seal - damaged,
stripped, shy se a le r
damaged. (A ls o check
CLUTCHES AND TRANSMISSIONS 7-43
b. W a ter in oil,
c. Pump to case gasket m ispositioned.
d. F oreign m a teria l between pump and case, o r b e­
tween pump co ver and body.
e. Case - porous, pump fa ce im p ro p erly machined.
f . Pump - shy of stock on mounting fa ces, porous
casting.
CASE POROSITY—REPAIR
T ran sm ission leaks caused by aluminum case po ro sity
have been su ccessfu lly re p a ired with the transm ission in
the veh icle by using the follow in g procedure.
1. Road test and b rin g the transm ission to operating
tem perature.
2. R aise the car and, with the engine running, locate the
source of the leak.
ing positions.
NOTE: The use of a m ir r o r w ill be helpful in
finding leaks.
3. Shut off engine and thoroughly clean area with a s o l­
vent and a ir dry.
4. Using the instruction of the m anufacturer, m ix a suf­
ficien t amount of epoxy cement, part #1360016, to
make the rep a ir.
5. W hile the tran sm ission is s till hot, apply the epoxy
to the area, making certain that the area is fu lly
covered.
6. A llo w epoxy cement to d ry fo r three hours and r e ­
test fo r leaks, as outlined in Steps 1 and 2.
OIL PRESSURE CHECK
W ith Car Stationary
Tran sm ission o il p ressu re gauge and engine tachom e­
te r should be connected and the o il p ressu res should
check as follow s:
1. P re s s u re s (P S I) indicated
speed with the vacuum modulator tube disconnected
and with engine at 1200 rpm.
Approxim ate
D rive
Altitude of Check
Neutral
(F t. Above
Park
Sea L e v e l)
139
0
2000 139
4000 139
6000 132
8000 125
117
10000
12000 110
14000 104
2. P re s s u re s (P S I) indicated
speed with the vacuum modulator tube connected,
and with sufficient engine speed to maintain 16 inches
Hg absolute m anifold p ressu re.
Check fo r leaks in a ll operat­
below are at 0 output
L -6 and
V -8 R ev e rs e
L I or L2
139 250
139 235
221
139
134 203
129 195
184
123
118 173
113 163
below are at 0 output
CHEVROLET TRUCK SERVICE MANUAL