Chevrolet 1977 light duty truck, Service Manual

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be tested for p ro p e r function and serviced, if necessary
(Also see m ain ten an ce schedule at end o f this section.)
Air Injection R eactor System
(A .I.R .)--C o n tro lled Com bustion
System (E.C.S.)
T h e Air Injection Reactor system should have the
drive belt inspected for w ear and tension every 24
m onths o r 30,000 miles (4 m o n th s or 6,000 miles Heavy
D uty Emission Vehicles), whichever occurs first. In
addition, complete effectiveness o f either system, as well
as full power an d p e rform ance, depends upon idle speed,
ig nition tim ing, an d idle fuel mixture being set
according to specification. A quality tune-up which
in clu d es these a d ju s tm e n ts should be p e r f o r m e d
periodically to assure norm al engine efficiency, operation
and p e rfo rm a n c e.
Evaporation C ontrol S ystem (E.C.S.)
Every 30,000 miles (24,000 miles Heavy Duty
Emission Vehicles) or 24 m onths, (more often under
dusty conditions) the filter in the base o f the canister
must be replaced and the canister inspected.
Early Fuel Evaporation (E.F.E.) System
First 7,500 miles or 12 m onths check valve for
freedom o f operation. A b in d in g condition must be
corrected. Check hoses for cracking, abrasion or
deterioration. Replace parts as necessary.
Air C leaner
CAUTION:
Do not remove the engine air
cleaner unless temporary removal is necessary
during repair or maintenance o f the vehicle.
When the air cleaner is removed backfiring can
cause fire in the engine compartment.
N O T E : U n d e r prolonged dusty driving conditions,
it is reco m m en d ed that these operations be
p e rfo rm e d more often.
Replace the engine air cleaner ele m ent und er
n o rm al o p e ra tin g conditions every 30,000 miles (12,000
miles Heavy D uty Emission Vehicles except C alifornia
350-400 engines, replace every 24,000 miles).
Fuel Filter
L ig h t D u ty E m ission V eh icles -R ep lac e
filter element
located in c a rb u re to r inlet every 12 m onths or 15,000
miles whichever occurs first, or, if an in-line filter is also
used, replace both filters every 30,000 miles.
Heavy Duty
E m ission V eh icles -R ep lac e
filter ele­
m ent in carb u reto r inlet every 12 m onths or 12,000 miles,
w hichever comes first, except C alifo rn ia 350-400 engines
should be replaced every 24 m onths or 24,000 miles.
A c c ele rato r Linkage
Lubricate with engine oil every 15,000 miles (12,000
miles Heavy D u ty Emission Vehicles) as follows:
1. On V8 engine, lubricate the ball stud at the
c arburetor lever.
2. On L6 engine, lubricate the two ball studs at the
carburetor lever and lubricate the lever m ou n tin g stud.
Do not lubricate the accelerator cable.
A U T O M A T IC T R A N S M IS S IO N
Fluid R ecom m endations
Use autom atic transmission fluids identified with the
m ark D E X R O N ® II.
Check the fluid level at each engine oil change
period.
Autom atic transmissions are frequently overfilled
because the fluid level is checked w hen the fluid is cold
and the dipstick indicates fluid should be added.
However, the low read in g is n o rm al since the level will
rise as the fluid tem perature increases. A level change o f
over 3 / 4 inch will occur as fluid tem perature rises from
60 F to 180°F.
Overfilling can cause fo am in g and loss o f fluid
through the vent. Slippage and transm ission failure can
result.
Fluid level too low can cause slipping, particularly,
w hen the transm ission is cold or the vehicle is on a hill.
Check the transmission fluid level with engine
running, the shift lever in PARK and the vehicle level.
N OTE: If the vehicle has recently been operated
for an extended period at high speed o r in city
traffic in hot w e ath er or the vehicle is being used to
pull a trailer, an accurate fluid level cannot be
d eterm ined until the fluid has cooled down -
usually about 30 minutes after the vehicle has been
parked.
Remove the dipstick and touch the transmission end
o f the dipstick cautiously to find out if the fluid is cool,
w arm or hot.
W ipe it clean an d re-insert until cap seats. Remove
dipstick and note readings.
• I f the fluid feels cool, about room tem perature
65 °F to 8 5 °F the level should be 1/8 to 3 /8 inch below
the ADD mark. The dipstick has two dim ples below the
"A D D ' mark to show this range (fig. 0B-1).
• If it feels w arm , the level should be close to the
ADD m a rk (either above or below).
( 6 5 8 5 F .) ( 1 8 ? 9 C . )
C O O L H O T
i - r ^ A D D 1 H O T '
\ ____
I
__ S ______________
W A R M
NOTE: DO NOT OVERFILL. It takes only one pint to raise
level from ADD to FULL with a hot transmission.