Chevrolet 10 Series 1970 Service Manual page 465

P ro p e r operation of the P o w e rg lid e transm ission may
be affected by a number of fa c to rs , a ll of which must be
considered when trouble in the unit is diagnosed.
P ro p e r trouble diagnosis can only be accom plished
when p e rfo rm e d in a thorough step by step procedure.
The fo llo w in g p rocedu re has been devised and tested and
is recom m ended fo r a ll trouble diagnosis com plaints and
if the s e r v ic e man w ill fo llo w this checking procedu re,
accurate and dependable diagnosis m ay be accom plished.
T his w ill resu lt in a savings of tim e, not only to the s e r v ­
ic e man, but to the custom er as w ell.
W A R M IN G UP TRANSM ISSIO N
B e fo re attem pting to check and/or c o r r e c t any com ­
plaints on the P o w e rg lid e tran sm ission it is absolutely
essen tial that the o il le v e l be checked and co rre c te d if
n ecessary. An o il le v e l which is eith er too high or too
low can be the cause of a number of abnormal conditions
fro m e x c e s s iv e noise to slippage in a ll ranges.
It must be rem em b ered that cold o il w ill slow up the
action of the hydraulic con trols in the transm ission. F or
this reason a trouble o r o il leak diagnosis should not be
attem pted until the tran sm ission has been w arm ed up by
eith er of the fo llow in g procedu res:
Shop W arm Up
1. Connect tachom eter to engine.
2. Set parking brake tight and start engine.
3. P la c e s e le c to r le v e r in " D" (d riv e ) range.
4. Adjust carb u retor id le speed adjusting screw to run
engine at approxim ately 750 rpm and operate in this
manner fo r two minutes. At the end of two minutes
o f operation, the tran sm ission w ill be su fficien tly
w arm ed up fo r diagnosis purposes.
NOTE: A t this point, readjust the engine idle
speed to 450-475 rpm in " D " range.
Road W a rm Up
D riv e the v e h ic le approxim ately 5 m iles with frequent
sta rts and stops.
NOTE: A t this point, make sure the engine idle
speed is set to 450-475 rpm in " D"
CHECKING FLUID LEVEL A N D C O N D IT IO N
Transmission a t O perating Tem perature
W ith the tran sm ission hot (a fte r veh icle has been driven
at least 15 m ile s ), the fluid le v e l should be between the
" F U L L " m ark and 1/4 inch below F U L L .
should be le v e l with the engine idling and the tran s­
m ission in P A R K .
Transmission at Room Tem perature (8 0 °F )
If the veh icle has not been driven su fficiently to brin g
the tran sm ission up to operating tem peratu re, the fluid
le v e l should be checked as follow s:
1. Apply the parking brake, put the s e le c to r le v e r in
P A R K , and start the engine. Note: Do Not Race the
Engine. M ove the s e le c to r le v e r through each range.
2. Im m ed iately check the flu id le v e l with the s e le c to r
le v e r in the P A R K position.
DIAGNOSIS
range.
The veh icle
The engine should be
CLUTCHES AND TRANSMISSIONS 7-35
running at a slow idle and the veh icle should be le v e l.
The fluid le v e l on the dipstick should be between the
" A D D " m ark and 1/4 inch below.
3. If additional fluid is required, add su fficien t fluid to
bring the le v e l to 1/4 inch below the "A D D " m ark on
the dipstick.
If the tran sm ission fluid le v e l can be c o r r e c tly estab­
lish ed at room tem perature (80°F) as described, when the
tran sm ission reaches norm al operating tem peratu re, the
flu id le v e l w ill appear at the " F U L L "
le v e l is set at 1/4 inch below the "A D D " m ark on the
dipstick to allow fo r expansion of the flu id which occurs
as the transm ission tem perature ris e s to its norm al op­
eratin g point of 180°F. DO N O T O V E R F IL L .
C A UTIO N: If flu id le v e l is too high, flu id may
be aerated by the planet c a r r ie r .
w ill cause turbulence in the con verter which w ill
resu lt in lost pow er, lo w er stall speed and lo w er
p ressu res in control circu its. L ow er flu id le v e l
to fu ll mark, then shut off engine to allow a ir
bubbles to w ork out of fluid.
When checking o il le v e l, a burned sm e ll and d is c o lo ra ­
tion indicate burned clutches or bands and the tra n sm is­
sion w ill have to be rem oved.
M A N U A L LINKAGE
Manual linkage adjustment and the associated neutral
safety switch are im portant fro m a safety standpoint. The
neutral safety switch should be adjusted so that the engine
w ill start in the Pa rk and Neutral positions only.
With the s e le c to r le v e r in the P a rk position, the parking
pawl should fr e e ly engage and prevent the veh icle fro m
F ig . 5 P G —Pressure Test Plug
m ark. The fluid
A era ted fluid
CHEVROLET TRUCK SERVICE MANUAL