Shop Warm Up; Road Warm Up; Checking Fluid Level And Condition - Chevrolet 10 1971 Series Chassis Service Manual

Proper operation of the Powerglide transmission may
be affected by a number of factors, all of which must be
considered when trouble in the unit is diagnosed.
Proper trouble diagnosis can only be accomplished
when performed in a thorough step by step procedure.
The following procedure has been devised and tested and
is recommended for all trouble diagnosis complaints and
if the service man will follow this checking procedure,
accurate and dependable diagnosis may be accomplished.
This will result in a savings of time, not only to the serv­
ice man, but to the customer as well.
W A R M IN G UP TR A N SM ISSIO N
Before attempting to check and/or correct any com­
plaints on the Powerglide transmission it is absolutely
essential that the oil level be checked and corrected if
necessary. An oil level which is either too high or too
low can be the cause of a number of abnormal conditions
from excessive noise to slippage in all ranges.
It must be remembered that cold oil will slow up the
action of the hydraulic controls in the transmission. For
this reason a trouble or oil leak diagnosis should not be
attempted until the transmission has been warmed up by
either of the following procedures:

Shop Warm Up

1. Connect tachometer to engine.
2. Set parking brake tight and start engine.
3. Place selector lever in "D " (drive) range.
4. Adjust carburetor idle speed adjusting screw to run
engine at approximately 750 rpm and operate in this
manner for two minutes. At the end of two minutes
of operation, the transmission will be sufficiently
warmed up for diagnosis purposes.
At this point, readjust the engine idle
NOTE:
speed to 450-475 rpm in "D " range.

Road Warm Up

Drive the vehicle approximately 5 miles with frequent
starts and stops.
At this point, make sure the engine idle
NOTE:
speed is set to 450-475 rpm in "D " range.
CHECKING FLUID LEVEL A N D CO N DITIO N
Transmission at Operating Temperature
With the transmission hot (after vehicle has been driven
at least 15 miles), the fluid level should be between the
"FU LL" mark and 1/4 inch below FULL. The vehicle
should be level with the engine idling and the trans­
mission in PARK.
Transmission at Room Temperature (80°F)
If the vehicle has not been driven sufficiently to bring
the transmission up to operating temperature, the fluid
level should be checked as follows:
1. Apply the parking brake, put the selector lever in
PARK, and start the engine. Note: Do Not Race the
Engine. Move the selector lever through each range.
2. Immediately check the fluid level with the selector
lever in the PARK position. The engine should be
DIAG NOSIS
running at a slow idle and the vehicle should be level.
The fluid level on the dipstick should be between the
"ADD" mark and 1/4 inch below.
3. If additional fluid is required, add sufficient fluid to
bring the level to 1/4 inch below the "ADD" mark on
the dipstick.
If the transmission fluid level can be correctly estab­
lished at room temperature (80°F) as described, when the
transmission reaches normal operating temperature, the
fluid level will appear at the "FULL" mark. The fluid
level is set at 1/4 inch below the "ADD" mark on the
dipstick to allow for expansion of the fluid which occurs
as the transmission temperature rises to its normal op­
erating point of 180°F. DO NOT OVERFILL.
CAUTION:
be aerated by the planet carrier. Aerated fluid
will cause turbulence in the converter which will
result in lost power, lower stall speed and lower
pressures in control circuits. Lower fluid level
to full mark, then shut off engine to allow air
bubbles to work out of fluid.
When checking oil level, a burned smell and discolora­
tion indicate burned clutches or bands and the transmis­
sion will have to be removed.
M A N U A L LINKAGE
Manual linkage adjustment and the associated neutral
safety switch are important from a safety standpoint. The
neutral safety switch should be adjusted so that the engine
will start in the Park and Neutral positions only.
With the selector lever in the Park position, the parking
pawl should freely engage and prevent the vehicle from
CLUTCHES AND TRANSMISSIONS 7-17
If fluid level is too high, fluid may
SERVO APPLY
PRESSURE
Fig. 5 P G — Pressure Test Plug
10-30 CHEVROLET TRUCK SERVICE MANUAL