Chevrolet 1974 Light Duty Truck User manual

FOREWORD
This manual includes theory of operation and procedures
for diagnosis, maintenance and adjustments, minor service
operations, and removal and installation for components of
Chevrolet Light Duty Trucks. Procedures involving dis
assembly and assembly of major components for these
vehicles are contained in the 1974 Chevrolet Passenger Car
and Light Duty Truck Overhaul Manual. Wiring diagrams for
1974 trucks are contained in a separate Wiring Diagram
Booklet.
The Section Index on the contents page enables the user to
quickly locate any desired section. At the beginning of each
section containing more than one major subject is a Table of
Contents, which gives the page number on which each major
subject begins. An Index is placed at the beginning of each
major subject within the section.
Summaries of Special Tools, when required, are found at
the end of major sections while specifications covering
vehicle components are presented at the rear of the manual.
This manual should be kept in a handy place for ready
reference. If properly used, it will enable the technician to
better serve the owners of Chevrolet built vehicles.
All information, illustrations and specifications contained
in this literature are based on the latest product information
available at the time of publication approval. The right is
reserved to make changes at any time without notice.

SECTION INDEX
1974
LIGHT DUTY
TRUCK
(SERIES 10-30)
CHASSIS SERVICE
MANUAL
SECTION NAME
0
GENERAL INFORMATION
AND LUBRICATION
1A
HEATER AND
AIR CONDITIONING
IB
BODY
2
FRAME
3
FRONT SUSPENSION
4-WHEEL DRIVE
4
REAR SUSPENSION
AND DRIVELINE
5
BRAKES
6
ENGINE
6K
ENGINE COOLING
6M
FUEL SYSTEM
6T
1MISSION CONTROL
SYSTEMS
6Y
ENGINE ELECTRICAL
7M
CLUTCH AND
MANUAL TRANSMISSION
7A
AUTOMATIC
TRANSMISSION
8
FUEL TANK AND
EXHAUST SYSTEM
9
STEERING
10
WHEELS AND TIRES
11
CHASSIS SHEET METAL
12
ELECTRICAL— BODY
AND CHASSIS
13
RADIATOR AND GRILLE
14
BUMPERS
15
ACCESSORIES
SPECIFICATIONS

#
SECTION 0
GENERAL INFORMATION AND LUBRICATION
CONTENTS OF THIS SECTION
General Information .................................................................. 0-1
Lubrication.................................................................................... 0-5
GENERAL INFORMATION
INDEX
Model Line Up............................................................... 0-1
Truck Model De ignation............................................. 0-1
Vehicle Identification Number and Rating Plate .... 0-1
Engine Number............................................................... 0-2
Unit and Serial Number Location ........................... 0-2
Service Part Identification Plate................................. 0-3
Key and Lock ............................................................... 0-3
Emergency Starting........................................................ 0-3
Towing............................................................................... 0-4
MODEL LINE UP
The 10 through 35 Serie truck model line-up for 1974
con i t of the model hown in the Chart in thi
ection.
Truck Model Design tion
A five digit number preceded by a letter i u ed to
de ignate truck model . For example, vehicle C 10703
would be: Conventional C, 4900 lb .-6800 lb . GVW 1,
42 in. -47 in. Cab-to-Axle dimen ion 07, Cha i cab 03,
a li ted below.
First Letter - Ch ssis
C - Conventional (Conventional Cab, Suburban)
G - Light Duty Forward Control
K - Four-Wheel Drive
P - Forward Control
First Number-GVW R nge
1 - 4500-7150 lb .
2 - 5500-8200 lb .
3 - 6200-14000 lb .
Second nd Third Numbers-
C b-To-Axle Dimension
05 - 30-35 in.
07 - 42-47 in.
08 - 48-53 in.
09 - 54-59 in.
10 - 60-65 in.
14 - 84-89 in.
Fourth nd Fifth Numbers-Body Styles
Pickup boxe , tailgate and drop gla , van bodie , and
trim are option .
03 - Cab
05 - Van (windowle )
06 - Suburban and Van (with window )
14 - Utility
32 - Motor Home Cha i
42 - Forward Control Cha i
63 - Four-Door Crew Cab
VEHICLE IDENTIFICATION NUMBER
AND RATING PLATE
A combination vehicle identification number and rating
plate u ed on all model (fig. 1) i located on the left
door pillar of CK model . On Forward Control model
(except P30 Motor Home Cha i ) it i attached to the
da h and toe panel.
The vehicle identification number tamped on the plate
decode into the information hown in Figure 2.
LIGHT DUTY TRUCK SERVICE MANUAL

0-2 GENERAL INFORMATION AND LUBRICATION
Fig. 1— Vehicle Identific tion Number nd R ting
Pl te Inform tion
Fig. 2— Vehicle Identific tion Number
ENGINE NUMBER
The engine number indicate manufacturing plant,
month and day of manufacture, and tran mi ion type.
A typical engine number would be F1210TFA, which
would breakdown thu :
F - Manufacturing Plant (F-Flint, T-Tonawanda)
12 - Month of Manufacture (December)
10 - Day of Manufacture (tenth)
T - Truck
FA - Tran mi ion and engine type
UNIT AND SERIAL NUMBER LOCATIONS
For the convenience of ervice technician and engineer
when writing up certain bu ine paper uch a
Warranty Report , Product Information Report , or
reporting product failure in any way, the location of the
variou unit number have been indicated. The e unit
number and their prefix or uffix are nece ary on the e
paper for variou rea on - uch a accounting, follow-
up on production, etc.
The prefixe on certain unit identify the plant in which
the unit wa manufactured and thereby permit proper
follow-up of the plant involved to get correction made
when nece ary.
Alway include the prefix in the number.
Axles
• Serie 10, 20 and P30 Code i tamped on Front of
Right Rear Axle Tube Inboard of Upper Control
Arm Bracket.
• Serie CG30 (except dual wheel) code i tamped at
the Forward Upper Surface of Carrier.
• Dual Wheel Part Number and Production Code i
tamped on Front of Right Axle Tube.
Tr nsmissions
• 3-Speed Tran mi ion Unit Number Located on
Lower Left Side of Ca e Adjacent to Rear of Cover.
• 4-Speed Tran mi ion Unit Number Stamped on
Rear of Ca e, Above Output.
• Turbo Hydra-Matic 350 Tran mi ion Unit Number
Located on Right Rear Vertical Surface of Oil Pan.
• The Turbo Hydra-Matic Tran mi ion 400 Serial
Number i Located on the Light Blue Plate on the
Right Side of the Tran mi ion.
Engines
• 6-Cylinder Engine Unit Number Located on Pad at
Right Hand Side of Cylinder Block at Rear of
Di tributor.
• 8-Cylinder Engine Unit Number Located on Pad at
Front, Right Hand Side of Cylinder Block.
Delcotrons
Delcotron Unit Serial Number Located at Top of
Rear Hou ing.
B tteries
Battery Code Number Located on Cell Cover Top of
Battery.
St rters
Starter Serial Number and Production Date
Stamped on Outer Ca e, Toward Rear.
DIVISION
C = CHEVROLET
T = GMT
ENGINE
DESIGNATION
Q = L6-250-1
T= L6-292-1
V = V8-
Y = V8-
Z = V8-
Q 1
CHASSIS TYPE
C = 2 WHEEL DRIVE
G=LIGHT DUTY
FORWARD CONTROL
K=4 WHEEL DRIVE
P =FORWARD CONTROL
BODY STYLE
2-Forw rd Control
ch ssis only
3-C b-ch ssis (Cut w y)
4-C b nd pickup box
5-Forw rd Control
ch ssis only
(Steel-Aluminum Body)
6-Suburb n body
7-Forw rd Control
(Rec. Vehicle Ch ssis)
8-Utility (Bl zer)
MODEL YEAR
4 = 1974 for ll
Series.
SEQUENTIAL NUMBER
ASSEMBLY PLANT
A-L kewood
B-B ltimore
C-Southg te
D-Dor ville
F-Flint <—
G-Fr mingh m
J-J nesville
K-Leeds
L-V n Nuys
N-Norwood
V-GM Truck-Ponti c
R-Arlington
S-St. Louis
T-T rrytown
U-Lordstown
W-Willow Run
Y-Wilmington
Z-Fremont
1-Osh w
2-Ste. Therese
LIGHT DUTY TRUCK SERVICE MANUAL

GENERAL INFORMATION AND LUBRICATION 0-3
SERVICE PARTS IDENTIFICATION
v .i.N .^ ^ ^ ^ H H H jw /B A S E H H H se|
V I N — VEHICLE IDENTIFICATION NUMBER
NO TE: TH E S PE CIA L EQ UIP MEN T LISTED BEL O W H AS BEEN IN STALLED ON
IMPORTANT: RETAIN THIS PLATE AS A PERMANENT RECORD
Fig. 3— Service P rts Identific tion Pl te
SERVICE PARTS IDENTIFICATION PLATE
The Service Part Identification Plate (fig. 3) i provided
on all Truck model . On mo t erie it will be located on
the in ide of the glove box door, or, on Forward Control
erie , it will be located on an inner body panel. The
plate li t the vehicle erial number, wheelba e, and all
Production option or Special Equipment on the vehicle
when it wa hipped from the factory including paint
information. ALWAYS REFER TO THIS INFORMATION
WHEN ORDERING PARTS.
KEYS AND LOCKS
Two key are provided with each vehicle. Different lock
cylinder operated by a eparate key are available a an
option for the liding ide load door and rear load door .
EMERGENCY STARTING
• Engine in vehicle with automatic tran mi ion
cannot be tarted by pu hing or towing the vehicle.
• Never tow a manual tran mi ion - equipped vehicle
to tart becau e the urge forward when the engine
tart could cau e a colli ion with the tow vehicle.
• A car with a di charged battery may be tarted by
tran ferring electrical power from a battery in
another car - called "jump tarting".
Jump St rting
The following procedure i for u e ONLY under the
following condition . Departure from the e condition
and procedure , could re ult in: (1) eriou per onal
injury (particularly to eye ) or property damage from
uch thing a battery explo ion, battery acid or electrical
burn , or (2) damage to electronic component in either
vehicle. If all the condition cannot be met, or if you are
uncertain about them, we trongly recommend for your
afety and that of your vehicle that you leave the tarting
to a competent mechanic.
• The battery in the other vehicle mu t be of the s me
nomin l volt ge, 12 volt , and mu t be neg tively
grounded. (All General Motor car , light truck
(10,000 GVWR and under), and motor home u e
12-volt, negatively grounded electrical y tem and
c n be u ed to jump tart one another.) The
nominal voltage and grounding of the other
vehicle’ battery may be determined by checking the
pecification in it owner’ manual. U e of a
boo ter battery of a higher nominal voltage, or
which i po itively grounded may re ult in eriou
per onal injury or property damage.
CAUTION: Never expose battery to open flame
or electric spark - battery action generates
hydrogen gas which is flammable and explo
sive. Don’t allow battery fl id to contact eyes,
skin, fabrics, or painted s rfaces - fl id is a
s lf ric acid sol tion which co ld ca se serio s
personal inj ry or property damage. Fl sh any
contacted area immediately with water. We r
eye protection such s industri l s fety
spect cles or goggles when working on or
ne r b ttery. Remove ring , metal watch
band and other metal jewelry before jump
tarting or working around a battery. Be
careful in u ing metal tool and equipment.
If uch metal hould contact the po itive
battery terminal (or metal in contact with it)
and any other metal on the vehicle, a hort
circuit may occur which could cau e per onal
injury. Batterie and battery acid hould
alway be kept out of reach of children.
Fig. 4— Booster B ttery C ble Ground Connection
L 6 ENGINE
V 8 ENGINE
LIGHT DUTY TRUCK SERVICE MANUAL

0-4 GENERAL INFORMATION AND LUBRICATION
To Jump St rt:
1. Po ition the two vehicle o they are not touching.
Set parking brake and place automatic tran mi ion
in "PARK" (neutral for manual tran mi ion) in
each vehicle. Al o turn off light , heater and all
other unnece ary electrical load .
2. Remove vent cap from both the boo ter and the
di charged batterie . Lay a cloth over the open vent
well of each battery. The e two action help reduce
the explo ion hazard alway pre ent in either
battery when connecting "live" boo ter batterie to
"dead" batterie .
3. Attach one end of one jumper cable to the po itive
terminal of the booster b ttery (identified by a red
color, " + " or "P" on the battery ca e, po t or
clamp) and the other end of ame cable to po itive
terminal of disch rged b ttery.
4. Attach one end of the remaining negative cable to
the negative terminal (black color, " or "N" of
the booster b ttery, and the other end to the engine
lift bracket on 6 cylinder model or the delcotron
mounting bracket on 8 cylinder model (do not
connect directly to neg tive post of dead battery) -
taking care that clamp from one cable do not
inadvertently touch the clamp on the other cable.
Do not lean over the battery when making thi
connection.
5. Start the engine in the vehicle that i providing the
jump tart (if it wa not running). Let run a few
minute , then tart the engine in the vehicle with
the di charged battery.
6. Rever e the above equence exactly when removing
the jumper cable . Rein tall vent cap and di po e
in a afe manner any cloth u ed to cover vent
well , a the cloth may have corro ive acid on
them.
PUSH STARTING
If your truck i equipped with a manual 3- peed or
4- peed tran mi ion, it can be tarted in an emergency
by pu hing. When being pu hed to tart the engine, turn
off all unnece ary electrical load , turn ignition to
"ON," depre the clutch pedal and place the hift lever
in high gear. Relea e the clutch pedal when peed
reache 10 to 15 mile per hour. Bumper and other part
contacted by the pu hing vehicle hould be protected
from damage during pu hing. Never tow the truck to
tart.
TOWING
All Except Four Wheel Drive Trucks
Normally your vehicle may be towed with all four wheel
on the ground for di tance up to 50 mile at peed of
le than 35 MPH. The engine hould be off and the
tran mi ion in neutral.
However, the rear wheel mu t be rai ed off the ground
or the drive haft di connected when the tran mi ion i
not operating properly or when a peed of 35 MPH or
di tance of 50 mile will be exceeded.
CAUTION: If a tr ck is towed on its front
wheels only, the steering wheel m st be sec red
with the wheels in a straight ahead position.
Four Wheel Drive Trucks
It i recommended that the truck be towed with the front
wheel off the ground. The truck can be towed, however,
with the rear wheel off the ground if there i damage in
the rear wheel area. In thi event, the tran mi ion
elector lever hould be placed in the "N" (neutral)
po ition and with conventional four wheel drive the
front drive di engaged. With Full Time four wheel drive
the tran fer ca e hould be in high. Towing peed
hould not exceed 35 MPH for di tance up to 50 mile .
If truck i towed on it front wheel , the teering wheel
hould be ecured to keep the front wheel in a traight
ahead po ition.
When towing the vehicle at low peed (approx. 20
MPH), for a very hort di tance only, the tran mi ion
mu t be in NEUTRAL and with conventional four wheel
drive the tran fer ca e MUST be in "TWO WHEEL
HIGH." With Full Time four wheel drive the tran fer
ca e hould be in high.
When towing the vehicle at fa ter peed for greater
di tance , the following tep MUST be taken:
• If front wheel are on the road, di connect the front
drive haft.
• If rear wheel are on the road, di connect the rear
drive haft.
STEEL TUBING REPLACEMENT
In the event that replacement of teel tubing i required
on brake line, fuel line, evaporative emi ion, and
tran mi ion cooling line , only the recommended teel
replacement tubing hould be u ed.
Only pecial teel tubing hould be u ed to replace brake
line. That i , a double wrapped and brazed teel tubing
meeting G.M. Specification 123 M. Further, any other
teel tubing hould be replaced only with the relea ed
teel tubing or it equivalent. Under no condition hould
copper or aluminum tubing be u ed to replace teel
tubing. Tho e material do not have ati factory fatigue
durability to with tand normal vehicle vibration .
All teel tubing hould be flared u ing the up et (double
lap) flare method which i detailed in Section 5 of thi
Manual.
LIGHT DUTY TRUCK SERVICE MANUAL

GENERAL INFORMATION AND LUBRICATION 0-5
VEHICLE LOADING
Vehicle loading 4mu t be controlled o weight do not
exceed the number hown on the Vehicle Identification
Number and Rating Plate for the vehicle.
In trailer hauling application , the vehicle rear end
weight at the ground with trailer attached mu t not
exceed the "Maximum Rear End Weight at Ground"
rating of the vehicle.
A typical example of a truck in a loaded condition i
hown in Figure 5. Note that the axle or GVW
capabilitie are not exceeded.
LOADED-MAXIMUM GVWR: 6000-LBS.
FRONT GAWR: 3250 LBS. REAR GAWR: 3582 LBS.
‘Front Curb 2100 lbs.
Front C rgo &
P ss. Lo d 400 lbs.
2500 lbs.
‘Re r Curb 1585 lbs.
Re r C rgo &
P ss. Lo d 1915 lbs-
3500 lbs.
TOTAL WEIGHT AT GROUND: 6000 lbs.
"Curb weight equ ls the weight of the vehicle without driver,
p ssenger or c rgo, but including fuel nd cool nt.
Fig. 5— Typic l Vehicle Lo ded Condition
LUBRICATION
INDEX
Maintenance Schedule ................................................. . 0-5
Engine.............................................................................. . 0-6
Oil and Filter Recommendation ............................ . 0-6
Drive Belt .................................................................... . 0-7
Po itive Crankca e Ventilation ................................ . 0-7
Air Injection Reactor Sy tem .................................. . 0-7
Controlled Combu tion Sy tem ............................... . 0-7
GM Evaporation Control Sy tem ........................... . 0-7
Manifold Heat Control Valve ................................. . 0-7
Air Cleaner................................................................... . 0-7
Fuel Filter..................................................................... . 0-7
Di tributor..................................................................... . 0-7
Governor....................................................................... . 0-7
Accelerator Linkage .................................................... . 0-7
Automatic Tran mi ion Fluid Recommendation . 0-7
Manual Tran mi ion
................................................... . 0-8
Tran mi ion Shift Linkage ....................................... . 0-8
Clutch...............................................................................
. 0-8
Rear Axle
Standard........................................................................ . 0-8
Propeller Shaft Slip Joint ......................................... . 0-8
Univer al Joint ............................................................. . 0-8
MAINTENANCE SCHEDULE
A eparate maintenance folder ha been provided with
each vehicle which contain a complete chedule and
brief explanation of the afety, emi ion control,
lubrication and general maintenance it require . The
Wheel Bearing
Front................................................................................ . 0-8
Rear.................................................................................
. 0-8
Brake Ma ter Cylinder................................................. . 0-9
Brake and Clutch Pedal Spring ............................... . 0-9
Parking Brake................................................................. . 0-9
Steering
Manual Steering Gear................................................ . 0-9
Steering Linkage and Su pen ion ........................... . 0-9
Hood Latch and Hood Hinge .................................... 0-9
Body Lubrication............................................................ 0-9
Four Wheel Drive
Propeller Shaft Centering Ball................................. . 0-10
Front Axle..................................................................... . 0-10
Air Vent Ho e.............................................................. . 0-10
Tran fer Ca e................................................................ . 0-10
Control Lever and Linkage...................................... . 0-10
Speedometer Adapter.................................................... . 0-10
Extended Vehicle Storage............................................ . 0-10
Lubrication Diagram
Conventional and Forward Control Model ......... . 0-17
Four Wheel Drive Model ........................................ . 0-18
1/2, 3/4 and 1 ton G Model
................................. . 0-19
maintenance folder information i upplemented by thi
ection of thi manual, a well a the eparate emi ion
control y tem folder al o furni hed with each vehicle.
Read all three publication for a full under tanding of
vehicle maintenance requirement .
LIGHT DUTY TRUCK SERVICE MANUAL

0-6 GENERAL INFORMATION AND LUBRICATION
The time or mileage interval for lubrication and
maintenance ervice outlined in thi ection are
intended a a general guide for e tabli hing regular
maintenance and lubrication period . Su tained heavy
duty and high peed operation or operation under
adver e condition may require more frequent ervicing.
ENGINE
Oil & Filter Recommend tions
The letter de ignation "SE" ha been e tabli hed to
corre pond with the requirement of GM 6136-M. "SE"
engine oil will be better quality and perform better than
tho e identified with "SA" through "SD" de ignation
and are recommended for all light-duty ga oline truck
regardle of model year and previou engine oil quality
recommendation .
Oil Ch nge Period
• U e only SE engine oil.
• Change oil each 4 month or 6,000 mile . If more
than 6,000 mile are driven in a 4-month period,
change oil each 6,000 mile .
• Change oil each 2 month or 3,000 mile , whichever
occur fir t, under the following condition :
—Driving in du ty condition
—Trailer pulling or camper u e.
—Frequent long run at high peed and high
ambient temperature .
—Motor Home u e.
—Stop and go type ervice uch a delivery truck ,
etc.
—Exten ive idling
—Short-trip operation at freezing temperature
(engine not thoroughly warmed-up).
• Operation in du t torm may require an immediate
oil change.
• Replace the oil filter at the fir t oil change, and
every econd oil change thereafter. AC oil filter
provide excellent engine protection.
The above recommendation apply to the fir t
change a well a ub equent oil change . The oil
change interval for the engine i ba ed on the u e of
SE oil and quality oil filter . Oil change interval
longer than tho e li ted above will eriou ly reduce
engine life and may affect the manufacturer’
obligation under the provi ion of the New Vehicle
Warranty.
A high quality SE oil wa in talled in the engine at
the factory. It i not nece ary to change thi
factory-in talled oil prior to the recommended
normal change period. However, check the oil level
more frequently during the break-in period ince
higher oil con umption i normal until the pi ton
ring become eated.
NOTE: Non-detergent and other low quality
oil are pecifically not recommended.
Oil Filter Type nd C p city
• Throwaway type, 1 quart U.S. mea ure, .75 quart
Imperial mea ure.
• 250 cu. in., 292 cu. in., AC Type PF-25. 350 cu. in.
454 cu. in., AC Type PF-35.
Cr nkc se C p city (Does Not Include Filter)
• 292 L6 Engine; 5 quart U.S. mea ure, 4.25 quart
Imperial mea ure.
• All other engine ; 4 quart U.S. mea ure, 3.25 quart
Imperial mea ure.
Recommended Viscosity
Select the proper oil vi co ity from the following chart:
RECOMMENDED SAE VISCOSITY NUMBER
10W, 5W-30, 10W-30, 10W-40
- 3 0 - 2 0 0 20 40 60 80 100
TEMPERATURE RANGE ANTICIPATED BEFORE NEXT OIL CHANGE, °F.
NOTE: SAE 5W-20 oil are not recommen
ded for u tained high- peed driving. SAE 30
oil may be u ed at temperature above 40°F.
SAE 5W-30 oil are recommended for all
ea on in vehicle normally operated in
Canada.
The proper oil vi co ity help a ure good cold and hot
tarting.
Checking Oil Level
The engine oil hould be maintained at proper level. The
be t time to check it i before operating the engine or a
the la t tep in a fuel top. Thi will allow the oil
accumulation in the engine to drain back in the
crankca e. To check the level, remove the oil gauge rod
(dip tick), wipe it clean and rein ert it firmly for an
accurate reading. The oil gauge rod i marked "FULL"
and "ADD OIL". If the oil i at or below the "ADD"
mark on the dip tick, oil hould be added a nece ary.
The oil level hould be maintained in the afety margin,
neither going above the "FULL" line nor below "ADD
OIL" line.
NOTE: The oil gauge rod i al o marked
"U e SE Engine Oil" a a reminder to u e
only SE oil .
Supplement l Engine Oil Additives
The regular u e of upplemental additive i pecifically
not recommended and will increa e operating co t .
However, upplemental additive are available that can
LIGHT DUTY TRUCK SERVICE MANUAL

GENERAL INFORMATION AND LUBRICATION 0-7
effectively and economically olve certain pecific
problem without cau ing other difficultie . For example,
if higher detergency i required to reduce varni h and
ludge depo it re ulting from ome unu ual operational
difficulty, a thoroughly te ted and approved additive -
"Super Engine Oil Supplement"- i available.
D ive Belts
Drive belt hould be checked every 6,000 mile or 4
month for proper ten ion. A loo e belt will affect water
pump and generator operation.
POSITIVE CRANKCASE VENTILATION
VALVE
Every 24,000 mile or 24 month the valve hould be
replaced. Connecting ho e , fitting and flame arre tor
hould be cleaned. At every oil change the y tem hould
be te ted for proper function and erviced, if nece ary.
AIR INJECTION REACTOR SYSTEM (A.I.R.)
CONTROLLED COMBUSTION SYSTEM
(C.C.S.)
The Air Injection Reactor y tem hould have the drive
belt in pected for wear and ten ion every 4 month or
6,000 mile , whichever occur fir t. In addition,
complete effectivene of either y tem, a well a full
power and performance, depend upon idle peed,
ignition timing, and idle fuel mixture being et
according to pecification. A quality tune-up which
include the e adju tment hould be performed
periodically to a ure normal engine efficiency, operation
and performance.
EXHAUST GAS RECIRCULATION SYSTEM
(EGR) -
At 12-month/12,000 mile interval when operating with
leaded fuel or at 24-month/24,000 mile interval when
u ing unleaded fuel remove, in pect, and if depo it
exi t, clean the EGR valve. In pect the EGR pa age in
the inlet manifold and clean a required. A damaged
EGR valve mu t be repaired or replaced.
GM EVAPORATION CONTROL SYSTEM
Every 24 month or 24,000 mile (more often under
du ty condition ) the filter in the ba e of the cani ter
mu t be replaced and the cani ter in pected.
MANIFOLD HEAT CONTROL VALVE
Fir t 6,000 mile and every 12,000 mile or 12 month
thereafter check valve for freedom of operation. If valve
haft i ticking, free it up with GM Manifold Heat Con
trol Solvent or it equivalent.
AIR CLEANER
CAUTION: Do not remove the engine air
cleaner nless temporary removal is necessary
d ring repair or maintenance of the vehicle.
When the air cleaner is removed backfiring can
ca se fire in the engine compartment.
NOTE: Under prolonged du ty driving
condition , it i recommended that the e
operation be performed more often.
011 Wetted P per Element Type
L-6 engine, replace every 12,000 mile . V-8 engine, every
12,000 mile in pect element for du t leak , hole or
other damage. Replace if nece ary. If ati factory,
rotate element 180° from originally in talled po ition.
Replace at 24,000 mile . Element mu t not be wa hed,
oiled, tapped or cleaned with an air ho e.
Cr nkc se Ventil tion Filter
(Loc ted Within Air Cle ner)
If o equipped, in pect every oil change and replace if
nece ary. Replace at lea t every 24,000 mile ; more
often under du ty driving condition .
FUEL FILTER
Replace filter element located in carburetor inlet every
12 month or 12,000 mile whichever occur fir t, or, if
an in-line filter i al o u ed, every 24,000 mile . Replace
in-line filter every 24,000 mile .
DISTRIBUTOR
Replace cam lubricator at 24,000 mile interval .
GOVERNOR
The attaching bolt hould be kept tight, the optionally
available governor hould be kept clean externally and
the filter element hould be replaced every 12,000 mile .
ACCELERATOR LINKAGE
Lubricate with engine oil every 24,000 mile a follow :
1. On V8 engine, lubricate the ball tud at the
carburetor lever.
2. On L6 engine, lubricate the two ball tud at the
carburetor lever and lubricate the lever mounting
tud. Do not lubricate the accelerator cable.
AUTOMATIC TRANSMISSION
FLUID RECOMMENDATION
U e only automatic tran mi ion fluid identified with
the mark DEXRON®—II or DEXRON®(or equivalent).
Check the fluid level at each engine oil change period.
To make an accurate fluid level check:
1. Drive vehicle everal mile , making frequent tart
and top , to bring tran mi ion up to normal
operating temperature (approximately 180-190°F).
2. Park vehicle on a level urface.
3. Place elector lever in "Park" and leave engine
running.
LIGHT DUTY TRUCK SERVICE MANUAL

0-8 GENERAL INFORMATION AND LUBRICATION
4. Remove dip tick and wipe clean.
5. Rein ert dip tick until cap eat .
6. Remove dip tick and note reading.
If oil level i at or below the ADD mark on the dip tick,
oil hould be added a nece ary. One pint rai e the
level from ADD to FULL. Do not overfill.
Under normal driving condition , the tran mi ion fluid
hould be changed every 24,000 mile . If the vehicle i
driven exten ively in heavy city traffic during hot
weather, or i u ed to pull a trailer, change fluid every
12,000 mile . Likewi e, operator of truck in commercial
u e where the engine idle for long period , hould
change fluid every 12,000 mile .
To Ch nge Turbo Hydr -M tic 400 nd Turbo Hydr -
M tic 350 fluid, remove fluid from the tran mi ion
ump, add approximately 7.5 pint U.S. mea ure (6.25
pint Imperial mea ure) for the Turbo Hydra-Matic 400
and 2 1/2 qt . U.S. mea ure (2 qt . Imperial mea ure) for
the Turbo Hydra-Matic 350 of fre h fluid, to return level
to proper mark on the dip tick.
Every 24,000 Miles— the Turbo Hydra-Matic 400
tran mi ion ump filter hould be replaced.
3-AND 4-SPEED MANUAL TRANSMISSION
LUBRICANT
Every 4 month or 6,000 mile , whichever occur fir t,
check lubricant level and add lubricant, if nece ary, to
fill to level of filler plug hole with SAE 80 or SAE 90 GL-
5 Gear Lubricant. If temperature below +32°F are
expected, u e SAE 80 GL-5 Gear Lubricant only.
For tho e vehicle normally operated in Canada, u e
SAE 80 GL-5 Gear Lubricant.
TRANSMISSION SHIFT LINKAGE
(MANUAL AND AUTOMATIC)
Every 6,000 mile or 4 month -lubricate hift linkage
and, on Manual tran mi ion floor control, lever
contacting face with water re i tant EP cha i lubricant
which meet General Motor Specification GM6031-M.
Clutch
The clutch pedal free travel hould be checked at regular
interval .
Lubricate the clutch cro - haft at fitting (on Serie 10
Forward Control model al o lubricate the clutch linkage
idler lever at fitting) every 6,000 mile or 4 month with
water re i tant EP cha i lubricant which meet General
Motor Specification GM 6031-M.
REAR AXLES
St nd rd
Every 4 month or 6,000 mile , whichever occur fir t,
check lubricant level and add lubricant, if nece ary, to
fill to level of filler plug hole. U e GL-5 Gear Lubricant
a hown in the following table. (For vehicle normally
operated in Canada, u e SAE 80 GL-5 Gear Lubricant.)
Outside Tempe atu e Viscosity Lub icant To Be Used
BELOW 10°F SAE 80
UP TO 100°F SAE 90
ABOVE 100°F
CONSISTENTLY SAE 140
On 20 or 30 Serie truck , drain lubricant every 24,000
mile . If vehicle i operated in exceptionally heavy work
or at continuou high peed , the lubricant hould be
changed every 12,000 mile . It may be nece ary to
change lubricant more often if vehicle i u ed off road in
du ty area .
PROPELLER SHAFT SLIP JOINTS
Propeller haft lip joint hould be lubricated every
6.000 mile or 4 month with water re i tant EP cha i
lubricant which meet General Motor Specification GM
6031-M.
UNIVERSAL JOINTS
All univer al joint are the needle bearing type.
Lubricate tho e univer al joint (depending on truck
model) equipped with lube fitting every 6,000 mile or 4
month with water re i tant EP cha i lubricant which
meet General Motor Specification GM 6031-M. More
frequent lube may be required on heavy duty or "Off
the Road" operation .
WHEEL BEARINGS
FrontNOTE: U e wheel bearing lubricant GM
Part No. 1051344 or equivalent. Thi i a
premium high melting point lubricant which
meet all requirement of General Motor
Specification GM 6031-M.
Due to the weight of the tire and wheel a embly it i
recommended that they be removed from hub before
lubricating bearing to prevent damage to oil eal. Then
remove the front wheel hub to lubricate the bearing .
The bearing hould be thoroughly cleaned before
repacking with lubricant.
Front wheel are equipped with tapered roller bearing
on all truck . Wheel bearing hould be lubricated every
24.000 mile . Do not mix wheel bearing lubricant .
CAUTION: " Long fibre" type greases sho ld
not be sed on roller bearing front wheels.
Re r
The rear wheel bearing receive their lubrication from
the rear axle. When in talling bearing which have been
cleaned, prelube with wheel bearing grea e.
LIGHT DUTY TRUCK SERVICE MANUAL

GENERAL INFORMATION AND LUBRICATION 0-9
BRAKE MASTER CYLINDER
Check ma ter cylinder fluid level in both re ervoir every
6,000 mile or 4 month . If the fluid i low in the
re ervoir, it hould be filled to a point about 1/4" from
the top rear of each re ervoir with Delco Supreme No.
11 Hydraulic Brake Fluid or equivalent.
BRAKE AND CLUTCH PEDAL SPRINGS
Lubricate brake and clutch pedal pring every 6,000
mile or 4 month with engine oil for all model .
PARKING BRAKE
Every 6,000 mile or 4 month clean and lubricate all
parking brake pivot point with water re i tant EP
cha i lubricant which meet General Motor Specifica
tion GM 6031-M.
STEERING
M nu l Steering Ge r
The teering gear i factory-filled with teering gear
lubricant. Sea onal change of thi lubricant hould not
be performed and the hou ing hould not be drained-no
lubrication i required for the life of the teering gear.
Every 36,000 mile , the gear hould be in pected for eal
leakage (actual olid grea e-not ju t oily film). If a eal i
replaced or the gear i overhauled, the gear hou ing
hould be refilled with No. 1051052 (13 oz. container)
Steering Gear Lubricant which meet GM Specification
GM 4673-M, or it equivalent.
NOTE: Do not u e EP Cha i Lube, which
meet GM Specification GM 6031-M, to
lubricate the gear. DO NOT OVER-FILL the
gear hou ing.
NOTE: Lubricate intermediate teering haft
with water re i tant EP cha i lubricant
which meet General Motor Specification
GM 6031-M every 6,000 mile or 4 month
on P-10 model only.
Power Steering System
Check the fluid level in-the pump re ervoir at each oil
change period. Add GM Power Steering Fluid or
DEXRON® automaticTran mi ion Fluid or equivalent a
nece ary to bring level into proper range on filler cap
indicator depending upon fluid temperature.
If at operating temperature (approximately 150°F—hot to
the touch), fluid hould be between "HOT" and
"COLD" mark .
If at room temperature (approximately 70°F), fluid
hould be between "ADD" and "COLD" mark . Fluid
doe not require periodic changing.
STEERING LINKAGE AND SUSPENSION
Maintain correct front end alignment to provide ea y
teering, longer tire life, and driving tability.
Fig. 6— Power Steering Fluid Level
Check control arm bu hing and ball joint for wear.
Lubricate tie rod , upper and lower control arm , and
ball joint at fitting with water re i tant EP cha i
lubricant which meet General Motor Specification GM
6031-M every 6,000 mile or 4 month .
Lubricate every 3,000 mile or 2 month whichever
occur fir t under the following condition :
• Driving in du ty or muddy condition .
• Exten ive off-road u e.
NOTE: Ball joint mu t be at + 10°F. or
more before lubricating.
Keep pring to axle U bolt and hackle bolt properly
tightened ( ee Specification Section for torque recom
mendation ). Check U bolt nut after the fir t 1,000 mile
of operation if the U bolt or U bolt nut are changed in
ervice.
HOOD LATCH AND HOOD HINGE
Every 6,000 mile or 4 month , whichever occur fir t,
lubricate hood latch a embly and hood hinge a embly
a follow :
1. Wipe off any accumulation of dirt or contamination
on latch part .
2. Apply Lubriplate or equivalent to latch pilot bolt
and latch locking plate.
3. Apply light engine oil to all pivot point in relea e
mechani m, a well a primary and econdary latch
mechani m .
4. Lubricate hood hinge .
5. Make hood hinge and latch mechani m functional
check to a ure the a embly i working correctly.
BODY LUBRICATION
Normal u e of a truck cau e metal-to-metal movement
at certain point in the cab or body. Noi e, wear and
improper operation at the e point will re ult when a
protective film of lubricant i not provided.
LIGHT DUTY TRUCK SERVICE MANUAL

0-10 GENERAL INFORMATION AND LUBRICATION
For expo ed urface , uch a door check , door lock
bolt , lock triker plate , dovetail bumper wedge , etc.,
apply a thin film of light engine oil.
Where oil hole are provided in body part a driple oil
can be afely u ed, but any lubricant hould be u ed
paringly, and after application all exce hould be
carefully wiped off.
The eat adju ter and eat track, ordinarily overlooked,
hould be lubricated with water re i tant EP cha i
lubricant which meet General Motor Specification GM
6031-M.
There are other point on bodie which may occa ionally
require lubrication and which are difficult to ervice.
Window regulator and control are confined in the
pace between the uphol tery and the out ide door panel.
Ea y acce to the working part may be made by
removing the trim. Door weather trip and rubber hood
bumper hould be lightly coated with a rubber
lubricant.
UNDERBODY MAINTENANCE
The effect of alt and other corro ive material u ed for
ice and now removal and du t control can re ult in
accelerated ru ting and deterioration of underbody
component uch a brake and fuel line , frame,
underbody floor pan, exhau t y tem, bracket , parking
brake cable . The e corro ive effect , however, can be
reduced by periodic flu hing of the underbody with plain
water. In geographic area having a heavy concentration
of uch corro ive material , it i recommended that the
complete underbody be in pected and flu hed at lea t
once a year, preferably after a winter’ expo ure.
Particular attention hould be given to cleaning out
underbody member where dirt and other foreign
material may have collected.
FOUR WHEEL DRIVE
Mo t lubrication recommendation and procedure for 4
wheel drive-equipped truck are the ame for corre
ponding component of conventional drive truck .
In addition, the following item require lubrication at the
interval mentioned.
Propeller Sh ft Centering B ll
A centering ball at the tran fer ca e end of the front
propeller haft on Four Wheel Drive Model hould be
lubricated every 6,000 mile with water re i tant EP
cha i lubricant which meet General Motor Specifica
tion GM 6031-M. More frequent lubrication may be
required on heavy duty off the road operation .
NOTE: A pecial needle no e grea e gun
adapter for flu h type grea e fitting i
required to lubricate the centering ball.
Front Axle
The front axle hould be checked every 6,000 mile or 4
month and refilled with SAE 90 GL-5 Gear Lubricant
when nece ary. With the differential at operating
temperature, fill to the level of filler plug hole. If
differential i cold, fill to level of 1/2" below the filler
plug hole. For vehicle normally operated in Canada u e
SAE 80 GL-5 Gear Lubricant.
Air Vent Hoses
Check vent ho e at front axle and at tran fer ca e for
kink and proper in tallation every 6,000 mile or 4
month .
Tr nsfer C se
Check the tran fer ca e level every 6,000 mile or 4
month and, if nece ary, add lubricant a follow :
Conventional Four Wheel Drive
Add SAE 80 or SAE 90 GL-5 Gear Lubricant to bring to
level of filler plug hole.
Full Time Four Wheel Drive
Add SAE 10W-30 or SAE 10W-40 engine oil to bring to
level 1 /2" below filler plug hole.
Control Lever nd Link ge
Since no grea e fitting i provided in the control lever it
i nece ary to bru h or pray engine oil on the lever
pivot point and on all expo ed control linkage every
6,000 mile or 4 month .
SPEEDOMETER ADAPTER
On vehicle o equipped, lubricate adapter at fitting with
water re i tant EP cha i grea e which meet General
Motor Specification GM 6031-M every 6,000 mile .
LIGHT DUTY TRUCK SERVICE MANUAL

GENERAL INFORMATION AND LUBRICATION 0-11
COMPLETE VEHICLE MAINTENANCE SCHEDULE
When To Perform Services
(Months o Miles, Whicheve Occu s Fi st)
Item
No Services
(Fo Details, See Numbe ed Pa ag aphs)
Every 4 months or 6,000 miles 1 Ch ssis Lubric tion
2*AFluid Levels
3 'Engine Oil
4Air Conditioning System
Every 6,000 miles 5 Tire Rot tion
At 1st oil ch nge— then every 2nd 6 *Engine Oil Filter
Every 12,000 miles 7 Re r Axle
Every 12 months or 12,000 miles 8‘ Cooling System
Every 24,000 miles 9Wheel Be rings
10 “Autom tic Tr nsmission
Every 36,000 miles 11 M nu l Steering Ge r
Every 4 months or 6,000 miles 12 Owner S fety Checks
13 Tires nd Wheels
14 Exh ust System
15 ‘ Drive Belts
16 Suspension nd Steering
17 Br kes nd Power Steering
Every 6,000 miles 18 Disc Br kes
Every 12 months or 12,000 miles 19 Drum Br kes nd P rking Br ke
20 Throttle Link ge
21 He dlights
22 Underbody
At 1st 4 months or 6,000 miles—
then t 12 month/12,000 mile
interv ls
23 Thermost tic lly Controlled Air Cle ner
24 C rburetor Choke
25 Timing, Dwell, C rb. Idle, Distr. nd Coil
26 M nifold He t V lve
At 1st 4 months or 6,000 miles 27 C rburetor Mounting
Every 6,000 miles 28 Sp rk Plugs (Vehicles using le ded fuels)
Every 12 months or
12,000 miles 29 EGR System (Vehicles using le ded fuels)
30 C rburetor Fuel Inlet Filter
31 Therm l V cuum Switch nd Hoses
32 V cuum Adv nce Solenoid nd Hoses
33 Tr nsmission Control Switch
34 Idle Stop Solenoid
35 PCV System
Every 24 months or
24,000 miles 36 Engine Compression
37 ECS System
38 Fuel C p, T nk nd Lines
39 AIR System
Every 24,000 miles 40 Air Cle ner Element
At 1st 24/24— then every 12/12 41 Sp rk Plug nd Ignition Coil Wires
*Also n Emission Control Service AAlso S fety Service
LIGHT DUTY TRUCK SERVICE MANUAL

0-12 GENERAL INFORMATION AND LUBRICATION
EXPLANATION OF COMPLETE
VEHICLE MAINTENANCE
SCHEDULE
Pre ented below i a brief explanation of each of the
ervice li ted in the preceding Complete Vehicle
Maintenance Schedule.
Vehicle operation under condition uch a heavy du t,
continuou hort trip , u e of other than unleaded or low
lead fuel or pulling trailer , i not con idered normal
u e and therefore more frequent maintenance will be
required. Such additional maintenance requirement are
included where applicable. Refer to the appropriate
ection of thi manual for additional detail on pecific
ervice . A li ting of recommended lubricant and fluid
i included at the end of thi li ting.
LUBE AND GENERAL MAINTENANCE
1. CHASSIS—Lubricate all grea e fitting in front
u pen ion, teering linkage, and con tant velocity
univer al joint. Al o lubricate tran mi ion hift
linkage, hood latch, hood hinge , and parking brake
cable guide and linkage, clutch linkage, propeller
haft lip joint, univer al joint and brake and
clutch pedal pring . Lubricate u pen ion and
teering linkage every 2 month or 3,000 mile
when operating under du ty or muddy condition
and in exten ive off-road u e. (See el ewhere in thi
ection for additional ervice required on four
wheel drive model .)
2. FLUID LEVELS—Check level of fluid in brake
ma ter cylinder*, power teering pump*, battery,
engine**, axle , tran mi ion** tran fer ca e and
wind hield wa her*. Engine coolant hould be
checked for proper level and freeze protection to at
lea t —20°F or to the lowe t temperature expected
during the period of vehicle operation.** Proper
engine coolant al o provide corro ion protection.
Any ignificant fluid lo in any of the e y tem or
unit could mean that a malfunction i developing and
corrective action hould be taken immediately. On
vehicle with di c brake , low fluid level in the brake
ma ter cylinder front re ervoir could al o be an
indicator that the di c brake pad need replacing.
3. ENGINE OIL**—Change each 4 month or 6,000
mile , whichever occur fir t, or each 2 month or
3,000 mile when the vehicle i operated under the
following condition : (a) driving in du ty condi
tion , (b) trailer pulling, (c) exten ive idling or (d)
hort-trip operation at freezing temperature (with
engine not thoroughly warmed-up). See el ewhere
in thi ection for additional detail on engine oil.
*Al o a afety Service
**Al o an Emi ion Control Service
4. AIR CONDITIONING—Check condition of air
conditioning y tem ho e and refrigerant charge at
ight gla (if o equipped). Replace ho e and/or
refrigerant if need i indicated.
5. TIRES—To equalize wear, rotate tire and adju t
tire pre ure a outlined in Section 10 of thi
manual.
6. ENGINE OIL FILTER*—Replace at the fir t oil
change and every other oil change thereafter.
7. REAR AXLE—Change lubricant at fir t 12,000 mile
on Po itraction axle . On 20 30 Serie truck ,
change lubricant every 24,000 mile . Change
lubricant every 12,000 mile on all type rear axle
under evere operating condition .
8. COOLING SYSTEM—At 12-month or 12,000 mile
interval , wa h radiator cap and filler neck with
clean water, pre ure te t y tem and radiator cap
for proper pre ure holding capacity, (tighten ho e
clamp and in pect condition of all cooling and
heater ho e **). Replace ho e every 24 month or
24,000 mile or earlier if checked, wollen or
otherwi e deteriorated.
Al o each 12 month or 12,000 mile , clean exterior of
radiator core and air conditioning conden er.** Every
24 month or 24,000 mile , drain, flu h, and refill the
cooling y tem with a new coolant olution.**
WHEEL BEARINGS — Clean and repack front wheel
bearing with a lubricant a pecified in the
"Recommended Fluid and Lubricant " ection in thi
ection.
10. AUTOMATIC TRANSMISSION FLUID**-Under
normal driving condition , change the tran mi ion
fluid and ervice the ump filter every 24,000 mile .
Under unu ual condition uch a con tant driving
in heavy city traffic during hot weather, trailer
pulling, etc., the e ervice hould be performed at
12,000-mile interval . See el ewhere in thi manual
for further detail on tran mi ion care.
11. MANUAL STEERING GEAR-Check for eal leakage
around the pitman haft and hou ing. If leakage i
evident ( olid grea e oozing out—not ju t oily film),
it hould be corrected immediately.
SAFETY MAINTENANCE
12. SAFETY CHECKS TO BE PERFORMED BY
OWNER—Li ted below are the afety check that
LIGHT DUTY TRUCK SERVICE MANUAL

GENERAL INFORMATION AND LUBRICATION 0-13
hould be made by the owner (item a thru u).
The e check hould be made regularly during
operation, at no greater interval than 4 month or
6,000 mile , whichever occur fir t, and more often
when the need i indicated. Any deficiencie hould
be brought to the attention of the dealer or another
ervice outlet, a oon a po ible.
a. STEERING COLUMN LOCK (if o equipped)-
Check for proper operation by attempting to
turn key to LOCK po ition in the variou
tran mi ion gear with vehicle tationary. Key
hould turn to LOCK po ition only when
tran mi ion control i in PARK on automatic
tran mi ion model or in rever e on manual
tran mi ion model . Key hould be removable
only in LOCK po ition.
b. PARKING BRAKE AND TRANSMISSION
"PARK" MECHANISM—Check parking brake
holding ability by parking on a fairly teep hill
and re training the vehicle with the parking
brake only. On vehicle with automatic tran 
mi ion , check the holding ability of the
"PARK" mechani m by relea ing all brake
after the tran mi ion elector lever ha been
placed in the "P" po ition.
CAUTION: Before making the two checks
below, be s re to have a clear distance ahead
and behind the vehicle, set the parking brake
and firmly apply the foot brake. Do not depress
accelerator pedal. Be prepared to t rn off
ignition switch immediately if engine sho ld
start.
c. STARTER SAFETY SWITCH (AUTOMATIC
TRANSMISSION) —Check tarter afety witch
by placing the tran mi ion in each of the
driving gear while attempting to tart the
engine. The tarter hould operate only in the
Park ("P") or Neutral ("N") po ition .
d. STARTER SAFETY SWITCH (MANUAL TRANS
MISSION) — To check, place the hift lever in
neutral, depre the clutch halfway, and attempt to
tart. The tarter hould operate only when clutch i
fully depre ed.
e. TRANSMISSION SHIFT INDICATOR—Check to
be ure automatic tran mi ion hift indicator
accurately indicate the hift po ition elected.
f. STEERING—Be alert to any change in teering
action. The need for in pection or ervicing may
be indicated by "hard" teering, exce ive free
play or unu ual ound when turning or parking.
g. WHEEL ALIGNMENT AND BALANCE—In addi
tion to abnormal tire wear, the need for wheel
alignment ervice may be indicated by a pull to
the right or left when driving on a traight and
level road. The need for wheel balancing i
u ually indicated by a vibration of the teering
*Al o a afety Service
**Al o an Emi ion Control Service
wheel or eat while driving at normal highway
peed .
h. BRAKES—Be alert to illumination of the brake
warning light or change in braking action, uch
a repeated pulling to one ide, unu ual ound
when braking or increa ed brake pedal travel.
Any of the e could indicate the need for brake
y tem in pection and/or ervice.
i. EXHAUST SYSTEM—Be alert to any change in
the ound of the exhau t y tem or a mell of
fume which may indicate a leak.
j. WINDSHIELD WIPERS AND WASHERS-Check
operation of wiper , a well a condition and
alignment of wiper blade . Check amount and
direction of fluid prayed by wa her during u e.
k. DEFROSTERS—Check performance by moving
control to "DEF" and noting amount of air
directed again t the wind hield.
1. REARVIEW MIRRORS AND SUN VISORS-
Check that friction joint are properly adju ted
o mirror and un vi or tay in the elected
po ition.
m. HORN—Blow the horn occa ionally to be ure
that it work .
n. LAP AND SHOULDER BELTS-Check belt ,
buckle , retractor , and anchor for cut , fraying
or weakened portion , loo e connection , dam
age, and for proper operation. Check to make
certain that anchor mounting bolt are tight.
o. HEAD RESTRAINTS—Check that head re
traint , if pre ent, adju t properly in the up
detent po ition , and that no component are
mi ing, damaged or loo e.
p. SEAT BACK LATCHES (if so equipped)— Check
to ee that eat back latche are holding by
pulling forward on the top of each folding eat
back.
q. LIGHTS AND BUZZERS—Check all in trument
panel illuminating and warning light , interior
light , licen e plate light , ide marker light ,
headlamp , parking lamp , tail lamp , brake
light , turn ignal , backup lamp , and hazard
warning fla her . Have omeone ob erve opera
tion of each exterior light while you activate the
control .
r. GLASS—Check for broken, cratched, dirty or
damaged gla on vehicle that could ob cure
vi ion or become an injury hazard.
. DOOR LATCHES — Check for po itive clo ing,
latching and locking.
t. HOOD LATCHES—Check to make ure hood
clo e firmly by lifting on the hood after each
clo ing. Check al o for broken, damaged or
mi ing part which might prevent ecure
latching.
LIGHT DUTY TRUCK SERVICE MANUAL

0-14 GENERAL INFORMATION AND LUBRICATION
u. FLUID LEAKS—Check for fuel, water, oil or
other fluid leak by ob erving the ground
beneath the vehicle after it ha been parked for
a while. (Water dripping from air conditioning
y tem after u e i normal.) If ga oline fume or
fluid are noticed at any time, the cau e hould
be determined and corrected without delay
becau e of the po ibility of fire.
13. TIRES AND WHEELS-Check tire for exce ive
wear, nail , gla , cut or other damage. Make
certain wheel are not bent or cracked and wheel
nut are tight. Uneven or abnormal tire wear may
indicate the need for alignment ervice. Tire
inflation pre ure hould be checked by the owner
at lea t monthly, or more often if daily vi ual
in pection indicate the need. Refer to Section 10 in
thi manual for information on tire tread wear
indicator .
14. EXHAUST SYSTEM—Check complete exhau t y 
tem and nearby body area for broken, damaged,
mi ing or mi po itioned part , open eam , hole ,
loo e connection or other deterioration which could
permit exhau t fume to eep into the pa enger
compartment. Du t or water in the pa enger
compartment may be an indication of a problem in
one of the e area . Any defect hould be corrected
immediately. To help in ure continued integrity,
exhau t y tem pipe and re onator rearward of
the muffler mu t be replaced whenever a new
muffler i in talled.
15. ENGINE DRIVE BELTS**— Check belt driving fan,
AIR pump, Delcotron, power teering pump and air
conditioning compre or for crack , fraying, wear
and ten ion.** Adju t or replace a nece ary.
It i recommended that belt be replaced every 24
month or 24,000 mile , whichever occur fir t.
16. SUSPENSION AND STEERING—Check for dam
aged, loo e or mi ing part , or part howing
vi ible ign of exce ive wear or lack of lubrication
in front and rear u pen ion and teering y tem.
Que tionable part noted hould be replaced
without delay.
17. BRAKES AND POWER STEERING—Check line and
ho e for proper attachment, leak , crack , chafing,
deterioration, etc. Any que tionable part noted
hould be replaced or repaired immediately. When
abra ion or wear i evident on line or ho e , the
cau e mu t be corrected.
18. DISC BRAKES— Be alert for di c brake wear
indicator ound ( ee Section 5 in thi manual for
de criptive detail ). Check brake pad and condi
tion of rotor while wheel are removed during tire
rotation. (Note below regarding more frequent
check al o applie to di c brake .)
19. DRUM BRAKES AND PARKING BRAKE-Check
drum brake lining and other internal brake
component at each wheel (drum , wheel cylinder ,
*Al o a afety Service
**Al o an Emi ion Control Service
etc.). Parking brake adju tment al o hould be
checked for drag and lubricated at every cha i
lube period.
NOTE: More frequent check hould be
made if driving condition and habit re ult
in frequent brake application.
20. THROTTLE LINKAGE— Check for damaged or
mi ing part , interference or binding. Any
deficiencie hould be corrected without delay.
21. HEADLIGHTS— Check for proper aim. Correct a
nece ary. More frequent check hould be made if
oncoming motori t ignal when light are already
on low beam, or if illumination of the area ahead
eem inadequate.
22. UNDERBODY—In geographic area u ing a heavy
concentration of road alt or other corro ive
material for now removal or road du t control,
flu h and in pect the complete under ide of the car
at lea t once each year, preferably after a winter’
expo ure. Particular attention hould be given to
cleaning out underbody member where dirt and
other foreign material may have collected.
EMISSION CONTROL MAINTENANCE
23. THERMOSTATICALLY CONTROLLED AIR
CLEANER—In pect in tallation to make certain that
all ho e and duct are connected and correctly
in talled. Al o check valve for proper operation.
24. CARBURETOR CHOKE—Check choke mechani m
for free operation. Any binding condition which
may have developed due to petroleum gum
formation on the choke haft or from damage
hould be corrected.
25. TIMING, DWELL, CARBURETOR IDLE, DISTRIBU
TOR AND COIL—Adju t ignition timing, dwell and
carburetor idle peed accurately (following the
pecification hown on the label under the hood) at
the fir t 4 month or 6,000 mile of operation then
at 12-month or 12,000-mile interval . Adju tment
mu t be made with te t equipment known to be
accurate.
Replace di tributor point every 12 month or 12,000
mile and replace cam lubricator every 24 month or
24,000 mile . In addition, carefully in pect the interior
and exterior of the di tributor cap, di tributor rotor and
coil for crack , carbon tracking, and terminal corro ion.
Clean or replace a nece ary at 12-month/12,000-mile
interval to prevent mi firing and/or deterioration.
Proper functioning of the carburetor i particularly
e ential to control of emi ion . Correct mixture for
emi ion compliance and idle quality have been pre et
by Chevrolet. Pla tic idle mixture limiter have been
in talled on the idle mixture crew to preclude
unauthorized adju tment. The e idle limiter are not to
be removed unle ome major carburetor repair or
replacement which affect the idle crew adju tment, ha
been nece ary.
LIGHT DUTY TRUCK SERVICE MANUAL

GENERAL INFORMATION AND LUBRICATION 0-15
At 24 month or 24,000 mile interval on all 10 Serie
vehicle , and on 20 Serie Suburban, Chevy Van and
Sportvan, and 30 Serie Sportvan vehicle (12 month or
12,000 mile interval on all other 20 and 30 Serie
vehicle ) or in ca e of a major carburetor overhaul, or
when poor idle quality exi t , idle mixture hould be
adju ted by a mechanical method (lean drop). The
alternate method for adju ting idle mixture i by CO
meter if accurate meter i available.
26. MANIFOLD HEAT VALVE-Some engine are
equipped with a manifold heat valve which hould
be in pected and repaired a nece ary to in ure
free operation.
27. CARBURETOR MOUNTING—Torque carburetor
attaching bolt and/or nut to compen ate for
compre ion of ga ket at fir t 4 month or 6,000
mile of vehicle operation, then at every 12,000
mile thereafter.
28. SPARK PLUGS—Replace at 6,000-mile interval
when operating with leaded fuel or at 12,000-mile
interval when u ing unleaded fuel . U e of leaded
fuel re ult in lead depo it on park plug and can
cau e mi firing at mileage le than 12,000 mile .
Where mi firing occur prior to 6,000 mile , park
plug in good condition can often be cleaned, te ted
and rein talled in an engine with acceptable re ult .
29. EXHAUST GAS RECIRCULATION SYSTEM (EGR)-
At 12-month/12,000 mile interval when operating
with leaded fuel or at 24-month/24,000 mile
interval when u ing unleaded fuel remove,
in pect, and if depo it exi t, clean the EGR valve.
In pect the EGR pa age in the inlet manifold and
clean a required. A damaged EGR valve mu t be
repaired or replaced.
30. CARBURETOR FUEL INLET FILTER—Replace filter
at 12-month/ 12,000-mile interval or more fre
quently if clogged.
31. THERMAL VACUUM SWITCH AND HOSES-Check
for proper operation. A malfunctioning witch mu t
be replaced. Check ho e for proper connection,
cracking, abra ion or deterioration and replace a
nece ary.
32. VACUUM ADVANCE SOLENOID AND HOSES-
Check both the vacuum and electrical function of
thi valve. An inoperative or leaking valve hould
be replaced. Check condition of wire and
connection . Check ho e for proper connection,
cracking, abra ion or deterioration and replace a
nece ary.
33. TRANSMISSION CONTROL SWITCH-Check the
electrical function of thi witch. An inoperative
witch hould be replaced. Check condition of wire
and connection .
34. IDLE STOP SOLENOID—Check for proper opera
tion. An inoperative olenoid mu t be replaced.
35. POSITIVE CRANKCASE VENTILATION SYSTEM
(PCV) —Check the PCV y tem for ati factory
operation at 12-month or 12,000-mile interval
*Al o a afety Service
**Al o an Emi ion Control Service
u ing a te ter. Replace the PCV valve at 24-month
or 24,000 mile interval , blow out PCV valve ho e
with compre ed air and replace the filter. The PCV
valve hould be replaced at 12-month or 12,000
mile interval when the vehicle i u ed in operation
involving heavy du t, exten ive idling, trailer
pulling, and hort trip u e at freezing temperature
where engine doe not become thoroughly warmed-
up.
The PCV filter hould be replaced at 12-month/12,000-
mile interval under du ty driving condition .
36. ENGINE COMPRESSION—Te t engine cranking
compre ion. If a problem exi t , have correction
made. Minimum compre ion recorded in any one
cylinder hould not be le than 70% of highe t
cylinder. For example, if the highe t pre ure in
any one cylinder i 150 pound , the lowe t allowable
pre ure for any other cylinder would be 105
pound (150 x 70% = 105).
37. EVAPORATION CONTROL SYSTEM (ECS)-Check
all fuel and vapor line and ho e for proper
connection and correct routing a well a condition.
Remove cani ter and check for crack or damage.
Replace damaged or deteriorated part a nece 
ary. Replace filter in lower ection of cani ter.
38. FUEL CAP, FUEL LINES AND FUEL TANK—In pect
the fuel tank, cap and line for damage which could
cau e leakage. In pect fuel cap for correct ealing
ability and indication of phy ical damage. Replace
any damaged or malfunctioning part .
39. AIR INJECTION REACTOR (AIR) SYSTEM HOSES
AND CONNECTIONS—Check AIR y tem ho e
and fitting for loo e connection and deterioration.
Te t diverter valve for proper operation. Malfunc
tioning diverter valve and deteriorated ho e mu t
be replaced.
40. AIR CLEANER ELEMENT—Replace the engine air
cleaner element under normal operating condition
every 12,000 mile (24,000 mile in V-8 engine
equipped 10 Serie vehicle, 20 Serie Suburban,
Chevy Van and Sportvan vehicle , and 30 Serie
Sportvan vehicle ). Operation of vehicle in du ty
area will nece itate more frequent element
replacement.
CAUTION: Do not operate the engine witho t
the air cleaner nless temporary removal is
necessary d ring repair or maintenance of the
vehicle. When the air cleaner is removed,
backfiring can ca se fire in the engine
compartment.
41. SPARK PLUG AND IGNITION COIL WIRES-
In pect park plug and ignition coil wire for
evidence of checking, burning, or cracking of
exterior in ulation and tight fit at di tributor cap,
coil, and park plug . Exterior of wire hould be
cleaned; any evidence of corro ion on end
terminal removed and wire replaced a nece ary
to prevent mi firing and/or deterioration.
LIGHT DUTY TRUCK SERVICE MANUAL

r
0-16 GENERAL INFORMATION AND LUBRICATION
RECOMMENDED FLUIDS b LUBRICANTS
USAGE FLUID/LUBRICANT
Powe stee ing system and GM powe stee ing fluid Pa t No.
pump ese voi 1050017 o equivalent— if not avail
able use DEXRON ® o
DEXRO N ® II automatic t ansmis
sion fluid
Diffe ential— standa d SAE-80 o SAE-90 GL-5 gea
lub icant (SAE-80 in Canada)
Diffe ential— Posit action Lub icant GM Pa t No. 1051022 o
equivalent
Manual stee ing gea Lub icant GM Pa t No. 1051052 o
equivalent
Manual t ansmission SAE-80 o SAE-90 GL-5 gea
lub icant (SAE-80 in Canada)
B ake system and maste cylinde Delco Sup eme 11 fluid o DOT-3
Clutch linkage (Man. t ans. only)
a. Pivot points Engine oil
b. Push od to clutch fo k joint, Chassis g ease meeting equi ements
and c oss shaft p essu e fitting of GM 6031-M
Manual t ansmission shift linkage. Engine oil
column shift
Shift linkage, floo shift Engine oil
Hood Latch assembly
a. Pivots and sp ing ancho Engine oil
b. Release pawl Chassis g ease
USAGE FLUID/LUBRICANT
Hood hinges Engine oil
Automatic t ansmission shift Engine oil
linkage
Chassis lub ication Chassis g ease meeting equi ements
of G M 6031-M
Constant Velocity Unive sal Joint G M Lub icant Pa t No. 1050679 o
C ease meeting equi ements of
GM 6040-M
Automatic t ansmission DEXRO N ®
o D EXRO N® II auto
matic t ansmission fluid
Pa king b ake cables Chassis g ease
F ont wheel bea ings Chassis g ease meeting equi ements
of GM 6031-M
Body doo hinge pins, station wagon Engine oil
tailgate hinge and linkage, station
wagon folding seat, fuel doo hinge,
ea compa tment lid hinges
Conve tible doo to lock wedge plates Stick-type lub icant
Windshield washe solvent GM Optikleen washe solvent
Pa t No. 1050001 o equivalent
Ene gize (Batte y) Colo less, odo less, d inking wate
Engine coolant Mixtu e of wate and a high quality
Ethylene Glycol base type
anti-f eeze confo ming to GM
Spec. 1899-M
Fig. 7— G Model Lifting Points
LIGHT DUTY TRUCK SERVICE MANUAL