Chevrolet 10 Series 1970 Service Manual page 461

General D e s c rip tio n ..............................................................................
Maintenance and A d ju stm e n ts............................................................
O il Level Check ................................................................................
Periodic O il Change .........................................................................
Periodic L o w Band A d ju s t m e n t .....................................................
Manual Shift Linkage Check and A d j u s t ....................................
Th ro ttle V alve L in k a g e ................................................................
Neutral Safety S w it c h ...................................................................
Th ro ttle Return Check Valve (D a s h p o t )....................................
Com ponent Parts R e p la c e m e n t..........................................................
Transmission R e p la ce m e n t..............................................................
Other Service O p e ra tio n s.....................................................................
Diagnosis ...........................................................................................
The case and con verte r housing of the two speed alum i­
num P o w e rg lid e T ran sm ission is a sin gle case aluminum
unit. When the manual con trol is placed in the d rive po­
sition, the tran sm ission autom atically shifts to low gea r
fo r in itia l veh icle m ovem ent. A s the truck gains speed
and depending on load and throttle position, an automatic
sh ift is made to high gear.
p rovid es a passing g e a r by returning the transm ission to
low range.
The o il pump assem bly is a conventional gear type and
the o il pump housing is of the la rg e diam eter type acting
as the fron t bulkhead of the tran sm ission .
con verter is a conventional three elem ent welded design
bolted to the engine flyw h eel which d riv e s through a two-
speed planetary gearset.
typical of the designs used in this type transm ission. The
aluminum P o w e rg lid e uses an output shaft mounted gov­
OIL LEVEL CHECK
The tran sm ission o il le v e l should be checked p e rio d i­
ca lly as recom m ended in Section 0. O il should be added
only when le v e l is on or below the " ADD" m ark on the
dip stick with o il hot o r at operating tem peratu re. The o il
le v e l dip stick is located at the righ t re a r of the engine
com partm ent. F ill with o il s p e c ified in Section 0.
In o rd er to check o il le v e l accu rately, the engine should
be id led with the tran sm ission o il hot and the control
le v e r in neutral (N ) position.
It is im portant that the le v e l be maintained no higher
than the " F U L L " m ark on the tran sm ission o il le v e l
gauge. DO N O T O V E R F IL L ,
at the fu ll m ark on the dip stick, it is just slig h tly be­
low the plan etary gear unit. If additional o il is added,
bringin g the o il le v e l above the fu ll m ark, the planetary
unit w ill run in the oil, foam ing and aerating the oil. This
aera ted o il c a rr ie d through the variou s o il p ressu re pas­
sages (low se rv o , r e v e r s e s ervo, clutch apply, con verter,
e tc .) may cause malfunction of the transm ission a ssem ­
bly, resu lting in cavitation noise in the con verter and
im p ro p er band o r clutch application. Overheating may
also occur.
If the tran sm ission is found consistently low on oil, a
ALUMINUM POWERGLIDE
Page
7-32
7-32
7-34
7-34
7-34
GENERAL DESCRIPTION
A fo r c e d downshift feature
The torque
The high clutch assem bly is
MAINTENANCE AND ADJUSTMENTS
fo r when the o il le v e l is
INDEX
7-31 Warming Up Transm ission........ ................................................................
7-31 Shop Warm U p .................................................................................. ......
Road Warm U p .................................................................................. ......
7-31
Checking Fluid Level and C o n d it io n .......................................................
7-31
Manual L in k a g e .................................................................................... ......
O il L e a k s ............................................................................................... ......
Basic Pressure Checks ......................................................................... ......
7-33
Wide O pen T h ro ttle Upshift Pressure C h e c k ................................. ......
7-33
Idle Pressure in Drive R a n g e ............. .............................. ............... ......
7-33
Manual " L o w " Range Pressure Check
D rive Range Overrun (C oast) Pressure .......................................... ......
Powerglide Shift P o i n t s ....................................................................... ......
7-35
ern o r which req u ires
The re v e r s e clutch assem bly is a m ultiple disc type
clutch. The steel p lates a re splined d ir e c tly to the case
w hile the fa ce plates are splined to the intern al o r rin g
gea r. The clutch piston operates within the re a r portion
of the case. The internal diam eter of the piston is sealed
to an in tegral hub portion of the case re a r bulkhead. The
outside dia m eter is sealed to a machined portion o f the
case. The piston is hydrau lically applied and is relea sed
by separate c o il springs.
bolted to the bottom o f the transm ission case and is ac­
cessib le fo r s e r v ic e by rem ovin g the o il pan assem bly.
The va lve body consists o f an upper and lo w e r body lo ­
cated on eith er side of a tran sfer plate.
m odulator is located on the le ft r e a r face of the tran s­
m ission case. The modulator va lve b ore is located in the
upper va lve body.
thorough inspection should be made to find and c o rre c t a ll
extern a l o il leaks.
PERIODIC OIL C H AN G E
The transm ission o il should be changed p e rio d ic a lly as
recom m ended in Section 0, and whenever tran sm ission is
to be rem oved fro m the veh icle fo r rep a irs.
1. Run engine
changing.
2. Be sure veh icle is le v e l o r ra ise fro m the re a r only.
3. Rem ove the o il pan drain plug and allow o il to drain
thoroughly into a pan or can.
4. Replace drain plug and r e f ill with approxim ately two
quarts of o il s p ecified in Section 0.
NOTE: T o r e f ill the transm ission, rem ove dip
stick fro m o il f i l l e r tube and r e fill transm ission
with o il sp ecified in Section 0.
shifting into a ll ranges at id le speed to f i l l a ll
o il passages, the engine should be run at 800-
1000 rpm with the transm ission in N eu tral until
the o il w arm s up, then add o il as requ ired to
ra is e the flu id le v e l to the fu ll mark on the dip
stick. R e fill capacity is
(U.S. m easure 1-3/4 qts. Im p eria l m easu re).
CLUTCHES AND TRANSMISSIONS 7-31
.......................................... ......
a hole through the output shaft.
The va lve body assem bly is
fo r one minute in neutral
Then, a f t e r
approxim ately 2 qts.
CHEVROLET TRUCK SERVICE MANUAL
7-35
7.35
7.35
7.35
7.35
7.36
7.36
7.35
7.36
7.36
7.35
7.37
The vacuum
p r io r to