Chevrolet 10 Series 1968, Service Manual

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LUBRICATION 0-15
if needed to bring level to full mark. DO NOT OVERFILL.
General Motors DEXRON Automatic Transmission
Fluid, Part numbers 1050568, 1050569, 1050570 which has
been especially formulated and tested for use in your
automatic transmission is recommended. Other Auto­
matic Transmission Fluids identified with the mark
DEXRON are also recommended.
EVERY 24,000 MILES, (**) more frequently if vehicle
is used to pull trailers, remove fluid from drain plug hole
and add approximately two (2) quarts U.S. Measure,
(1-2/3 quarts Imperial Measure) of new fluid. Operate
transmission through all shift ranges and recheck fluid
level as described above.
A drain plug is provided. It is not necessary to remove
the pan unless the fluid has a ‘ 'burnt" odor or appears
dark in color.
Lubricate shift linkage with water resistant EP chassis
lubricant which meets General Motors specification
GM 6041-M.
Powerglide Low Band Adjustment—At the first trans­
mission fluid change, have your Chevrolet dealer adjust
the Powerglide low band.
TURBO HYDRA-MATIC
Lubrication of your Turbo Hydra-Matic will, except
for fluid capacity and filter change listed below, follow
the Powerglide transmission recommendations. After
checking transmission fluid level it is important that the
dip stick be pushed all the way into the fill tube.
Every 24,000 Miles
After removing fluid from the transmission sump,
approximately 7.5 pints U.S. measure (6.25 pints Imperial
measure) of fresh fluid will be required to return level
to proper mark on the dip stick.
Every 24,000 Miles
The transmission sump strainer should be replaced.
SYNCHROMESH
The lubricant level in the housing should be checked
every 6,000 miles with unit at operating temperatures.
Lubricant should be level with bottom of fille r plug hole.
“ Multi-Purpose" gear lubricant meeting U.S. Army
Ord. Spec. MIL-L-2105B is recommended if additions
are required to bring up the lubricant level. The “ Gear
Lubricant Viscosity Table” on the following page shows
the proper viscosity lubricant to be used during vehicle
operation.
TRANSMISSION CONTROLS
The steering column manual shift mechanism on 1/2
Ton and 3/4 Ton models equipped with 3 speed trans­
mission is factory lubricated and should not require
periodic lubrication. However, should the shifting effort
become noticeably greater, lubricate all linkage points
with engine oil.
40-80 SERIES
ALLISON AUTOMATIC TRANSMISSION
Every 2,000 miles the fluid level should be checked
and fluid added as described below when necessary.
**This recommendation applies only to 10 Series Models.
For 20-30 Series Models drain period should be every
12,000 miles.
"U se only General Motors Automatic Transmission Fluid
or DEXRON Automatic Transmission Fluid.”
A good grade of 10W engine oil may be used tem­
porarily in emergencies, but must be replaced with
Automatic Transmission Fluid as soon as possible.
Checking Fluid
1. Start engine, set parking brake and move control
lever into (" 3 - HI” ) position. Run engine at 1,000
rpm until engine and transmission have reached
normal operating temperature.
2. Remove any dirt or gravel from area around in­
dicator in right side of engine compartment. With
engine running at 1,000 rpm remove indicator from
case, wipe clean, reinsert and carefully withdraw
again.
C A U TIO N :
Exercise care to prevent dirt from
entering fille r tube when checking fluid level.
Add fluid only when level reaches L mark (1 qt. low)
on the indicator.
3. With engine operating at 1,000 rpm add sufficient
"Automatic Transmission Fluid-Type A ” or “ Type
C” —to bring level to full mark on indicator.
CA U TIO N :
Fluid level should never be higher
than “ F ” mark on indicator when fluid is
at operating temperature. An excessively full
transmission will result in aeration of the fluid.
The expanding fluid may then be forced out of
the fille r tube. Sufficient fluid may be lost to
seriously damage the transmission.
4. Reinstall indicator and turn the cap 1/4 turn to lock.
Draining and Refilling
Transmission lubricant should be changed and the
filter replaced after the first 6,000 miles of operation.
Drain, replace the filter, and refill the transmission
every 12,000 miles thereafter if used in normal highway
operation; every 12,000 miles, or oftener, if used for
off highway operation, city stop-and-go service, or other
severe service. Approximately 9 qts. of fluid are re ­
quired to refill the transmission after the pan has been
drained. Drain immediately after operation—while fluid
is still warm. Do not flush transmission after draining.
SYNCHROMESH (INCL. AUX. 4-SPEED)
The lubricant level in the housing should be checked
every 6,000 miles or oftener under severe operating
conditions and with unit at operating temperatures, lu­
bricant should be level with bottom of fille r plug hole.
The following Table shows the proper viscosity “ Multi-
Purpose” gear lubricant to be used during vehicle
operation.
GEAR LUBRICANT VISCOSITY TABLE
Outside Temperature Viscosity Lubricant To Be Used
Below 10°F
SAE 80
Up to 100°F
SAE 90
Above 100°F
Consistently
SAE 140
Either SAE 90 “ Multi-Purpose” gear lubricant or
SAE 90 Straight Mineral Oil may be used. It is recom­
mended that any additions required to bring up the
CHEVROLET TRUCK SERVICE MANUAL