A U T O M A T IC T R A N S M IS S IO N
7 A -3 5
5. Road test vehicle.
a. Install oil pressure gauge.
b. Road test using all selective ranges, noting when
discrepancies in operation or oil pressure occur.
c. Attempt to isolate the unit or circuit involved in
the malfunction.
d. If engine performances indicates an engine
tune-up is required, this should be performed
before road testing is completed or transmission
correction attempted. Poor engine performance
can result in rough shifting or other
malfunctions.
OIL CHECKING PROCEDURES
Before diagnosis of any transmission complaint is
attempted, there must be understanding of oil checking
procedure and what appearance the oil should have.
Many times a transmission malfunction can be traced to
low oil level, improper reading of dipstick, or oil
appearance; therefore, a careful analysis of the
condition of oil and the level may eliminate needless
repairs.
When checking oil level, proceed as follows:
1. Engine Running.
2. Vehicle on level surface.
3. Brakes applied.
4. Move lever through all ranges.
5. Place transmission in "PARK".
6. Check oil level.
7. If oil is low, check for possible causes. Level should
be between the "Add" and "Full" marks at normal
operating temperature (180°F.) This temperature is
obtained after at least 15 miles of expressway
driving or equivalent city driving.
If the transmission is not at operating temperature,
the oil level should be approximately 1 /4" below the
"Add" mark with the oil at approximately 70°F.
(Room temperature.) If the oil level is correctly
established at room temperature (70°F.), it should be
at the "Full" mark on the dip stick when the
transmission reaches normal operating temperature
(180°F.).
When the dipstick is removed, it should be noted
whether the oil is devoid of air bubbles or not. Oil with
air bubbles gives an indication of an air leak in the
suction lines, which can cause erratic operation and
slippage. Water in the oil imparts a milky, pink cast to
the oil and can cause spewing.
CAUTION:
Do not overfill transmission
,
as this
will cause foaming and loss of oil through the
vent pipe.
OIL LEAK DIAGNOSIS
Determining Source of Oil Leak
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 locate the point at which
the oil is leaking is 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 - engine or transmission.
Oil leaks around the engine and transmission are
generally carried toward the rear of the vehicle by 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 a leak,
proceed as follows:
1. Degrease underside of transmission.
2. Road test to get unit at operating temperature.
3. Inspect for leak with engine running.
4. With engine off, check for oil leaks due to the
raised oil level caused by drain back.
Possible Points of Oil Leak
1. Transmission Oil Pan Leak.
a. Attaching bolts not correctly torqued.
b. Improperly installed or damaged pan gasket.
c. Oil pan gasket mounting face not flat.
2. Extension Housing.
a. Attaching bolts not correctly torqued.
b. Rear seal assembly damaged or improperly
installed.
c. Square seal, extension to case, damaged or
improperly installed.
d. Porous casting. See subparagraph C.
3. Case Leak.
a. Filler pipe "O " ring seal damaged or missing;
misposition of filler pipe bracket to engine.
b. Modulator assembly "O " ring seal damaged or
improperly installed.
c. Detent cable connector "O " ring seal damaged
or improperly installed.
d. Governor cover not tight, gasket damaged or
leak between case face and gasket.
e. Speedometer gear "O" ring damaged.
f. Manual shaft seal damaged or improperly
installed.
g. Line pressure tap plug loose.
LIGHT DUTY TRUCK SERVICE MANUAL
Summary of Contents for Light Duty Truck 1973
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Page 53: ...HEATER AND AIR CONDITIONING 1A 27 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 115: ...LIGHT DUTY TRUCK SERVICE M A N U A L HEATER AND AIR CONDITIONING 1A 89...
Page 123: ...BODY 1B 3 Fig 6 Typical 06 Van LIGHT DUTY TRUCK SERVICE MANUAL...
Page 149: ...BODY 1B 29 Fig 84 Body Mounting 06 Fig 85 Body Mounting 14 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 171: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 2 Frame Horizontal Checking Typical FRAME 2 3...
Page 173: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 4 10 30 Series Truck Frame FRAME 2 5...
Page 174: ...2 6 FRAME LIGHT DUTY TRUCK SERVICE MANUAL Fig 5 Underbody Reference Points G Van...
Page 185: ...FRONT SUSPENSION 3 11 Fig 16 Toe out on Turns LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 351: ...ENGINE 6 15 Fig ID Sectional View of Eight Cylinder Engine LIGHT DUTY TRUCK SERVICE MANUAL...
Page 375: ...EN G IN E 6 39 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 376: ...6 4 0 ENGINE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 377: ...ENG IN E 6 41 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 378: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 37L K Series Engine Front Mount 6 42 ENG INE...
Page 400: ...6 6 4 ENG INE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 401: ...ENG IN E 6 65 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 402: ...6 6 6 ENGINE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 403: ...E NG IN E 6 67 Fig 36V C Series Engine Mounts LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 423: ...EN G IN E C OOLING 6K 13 Fig 16 Overheating Chart LIGHT DUTY TRUCK SERVICE MANUAL...
Page 424: ...6 K 1 4 ENG INE COOLING Fig 17 Coolant Loss Chart LIGHT DUTY TRUCK SERVICE MANUAL...
Page 456: ...6M 32 ENGINE FUEL Fig K15 Accelerator Controls G Van L 6 LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 512: ...Fig 18e Vacuum Advance Diagram V8 Engine...
Page 516: ...6 T 2 4 E M IS S IO N CONTROL SYSTEMS LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 593: ...CLUTCHES MANUAL TRANSMISSIONS 7M 3 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 598: ...7M 8 CLUTCHES MANUAL TRANSMISSIONS LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 743: ...FUEL TANKS AND EXHAUST 8 13 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 744: ...8 14 FUEL TANKS AND EXHAUST LIGHT DUTY TRUCK SERVICE MANUAL...
Page 760: ...8 30 FUEL TANKS AND EXHAUST Fig 40 Exhaust Pipe P Models LIGHT DUTY TRUCK SERVICE MANUAL...
Page 761: ...FUEL TANKS AND EXHAUST 8 31 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 763: ...FUEL TANKS AND EXHAUST 8 33 LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 832: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 106 Power Steering Pump Mounting Typical 9 66 STEERING...
Page 833: ...PUMP ASSEMBLY STEERING GEAR TYPICAL SMALL V8 TYPICAL LARGE V8 STEERING 9 67...
Page 861: ...STEERING 9 95 Fig 134 Power Steering Pump Leakage LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 886: ...11 10 CHASSIS SHEET METAL LIGHT DUTY TRUCK SERVICE MANUAL...
Page 891: ...ELECTRICAL BODY AND CHASSIS 12 5 LIGHT DUTY TRUCK SERVICE MANUAL...
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