Aluminum Powerglide; Oil Level Check; Periodic Oil Change - Chevrolet 10 1971 Series Chassis Service Manual

General D escription................................................................................ ..... 7-13
Maintenance and A djustm ents................................................................... 7-13
O il Level Check ........................................................................................ 7-13
Periodic O il Change ................................................................................. 7-13
Periodic Low Band A d ju s tm e n t....................................................... ..... 7-14
Manual Shift Linkage Check and A d ju s t .......................................... 7-14
Throttle Valve L in k a g e .................................................................. ......7-15
Neutral Safety S w itc h .......................................................................... 7-15
Throttle Return Check Valve (Dashpot) .......................................... 7-15
Component Parts R e p lac e m e nt....................................... .................... ..... 7-16
Transmission Replacem ent................................................................ ..... 7-16
Other Service Operations....................... ..................................................... 7-16
Diagnosis .............................................................................................. ..... 7-17
The case and converter housing of the two speed alumi­
num Powerglide Transmission is a single case aluminum
unit. When the manual control is placed in the drive po­
sition, the transmission automatically shifts to low gear
for initial vehicle movement. As the truck gains speed
and depending on load and throttle position, an automatic
shift is made to high gear. A forced downshift feature
provides a passing gear by returning the transmission to
low range.
The oil pump assembly is a conventional gear type and
the oil pump housing is of the large diameter type acting
as the front bulkhead of the transmission. The torque
converter is a conventional three element welded design
bolted to the engine flywheel which drives through a two-
speed planetary gearset. The high clutch assembly is
typical of the designs used in this type transmission. The
aluminum Powerglide uses an output shaft mounted gov­

OIL LEVEL CHECK

The transmission oil level should be checked periodi­
cally as recommended in Section 0. Oil should be added
only when level is on or below the " ADD" mark on the
dip stick with oil hot or at operating temperature. The oil
level dip stick is located at the right rear of the engine
compartment. Fill with oil specified in Section 0.
In order to check oil level accurately, the engine should
be idled with the transmission oil hot and the control
lever in neutral (N) position.
It is important that the level be maintained no higher
than the " FULL" mark on the transmission oil level
gauge. DO NOT OVERFILL, for when the oil level is
at the full mark on the dip stick, it is just slightly be­
low the planetary gear unit. If additional oil is added,
bringing the oil level above the full mark, the planetary
unit will run in the oil, foaming and aerating the oil. This
aerated oil carried through the various oil pressure pas­
sages (low servo, reverse servo, clutch apply, converter,
etc.) may cause malfunction of the transmission assem­
bly, resulting in cavitation noise in the converter and
improper band or clutch application. Overheating may
also occur.
If the transmission is found consistently low on oil, a

ALUMINUM POWERGLIDE

GENERAL DESCRIPTION
MAINTENANCE A N D ADJUSTMENTS
INDEX
Warming Up Transmission . . . ..............................................................
Shop Warm U p .....................................................................................
Road Warm U p ................................................................ ....................
Checking Fluid Level and C o n d itio n ..................................................
Manual L inkage .......................................................................................
Oil L e ak s..................................................................................................
Basic Pressure Checks ............................................................................
Wide Open Throttle Upshift Pressure C h e ck..................................
Idle Pressure in Drive R a n g e ...................... .......................................
Manual " Low " Range Pressure Check .....................................
Drive Range Overrun (Coast) Pressure ............................................
Powerglide Shift P o in ts .........................................................................
ernor which requires a hole through the output shaft.
The reverse clutch assembly is a multiple disc type
clutch. The steel plates are splined directly to the case
while the face plates are splined to the internal or ring
gear. The clutch piston operates within the rear portion
of the case. The internal diameter of the piston is sealed
to an integral hub portion of the case rear bulkhead. The
outside diameter is sealed to a machined portion of the
case. The piston is hydraulically applied and is released
by separate coil springs. The valve body assembly is
bolted to the bottom of the transmission case and is ac­
cessible for service by removing the oil pan assembly.
The valve body consists of an upper and lower body lo­
cated on either side of a transfer plate. The vacuum
modulator is located on the left rear face of the trans­
mission case. The modulator valve bore is located in the
upper valve body.
thorough inspection should be made to find and correct all
external oil leaks.

PERIODIC OIL CHANGE

The transmission oil should be changed periodically as
recommended in Section 0, and whenever transmission is
to be removed from the vehicle for repairs.
1. Run engine for one minute in neutral prior to
changing.
2. Be sure vehicle is level or raise from the rear only.
3. Remove the oil pan drain plug and allow oil to drain
thoroughly into a pan or can.
4. Replace drain plug and refill with approximately two
quarts of oil specified in Section 0.
To refill the transmission, remove dip
NOTE:
stick from oil filler tube and refill transmission
with oil specified in Section 0. Then, a f t e r
shifting into all ranges at idle speed to fill all
oil passages, the engine should be run at 800-
1000 rpm with the transmission in Neutral until
the oil warms up, then add oil as required to
raise the fluid level to the full mark on the dip
stick. Refill capacity is approximately 2 qts.
(U.S. measure 1-3/4 qts. Imperial measure).
CLUTCHES AND TRANSMISSIONS 7-13
10-30 CHEVROLET TRUCK SERVICE MANUAL
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