Chevrolet 1980 Light Duty Truck User manual

FOREWORD
This manual includes procedures for diagnosis, maintenance and adjust
ments, minor service operations, and removal and installation for com
ponents of hevrolet Light Duty Trucks. Procedures involving disassembly
and assembly of major components for these vehicles are contained in the
1980 hevrolet Passenger ar and Light Duty Truck Unit Repair (Overhaul)
Manual. Wiring diagrams for 1980 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 ontents, 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, and specifications are found
at end of major sections.
When reference is made in this manual to a brand name, number, or
specific tool, an equivalent product may be used in place of the recom
mended item.
This manual should be kept in a handy place for ready reference. If pro
perly used, it will enable the technician to better serve the owners of hev
rolet built vehicles.
All information, illustrations and specifications contained in this literature
are based on the latest product information available at the time of publi
cation approval. The right is reserved to make changes at any time without
notice.

IMPORTANT SAFETY NOTICE
Proper service and repair is important to the safe, reliable operation of all
motor vehicles. The service procedures recommended and described in this
service manual are effective methods for performing service operations.
Some of these service operations require the use of tools specially designed
for the purpose. The special tools should be used when and as recommended.
It is important to note that this manual contains various autions and
Notices which should be carefully read in order to minimize the risk of
personal injury to service personnel or the possibility that improper service
methods will be followed which may damage the vehicle or render it unsafe.
It also is important to understand that these autions and Notices are not
exhaustive. The manufacturer could not possibly know, evaluate and advise
the service trade of all conceivable ways in which service might be done
or of the possible hazardous consequences of each way. onsequently,
the manufacturer has not undertaken any such broad evaluation. Accord
ingly, anyone who uses a service procedure or tool which is not recommend
ed must first satisfy himself thoroughly that neither his safety nor vehicle
safety will be jeopardized by the service method he selects.

TABLE OF CONTENTS SECTION
1980
LIGHT DUTY
TRU K
(SERIES 10-35)
HASSIS SERVI E
MANUAL
AUTION
These vehicles contains some parts dimensioned in the metric
system as well as in the customary system. Some fasteners are
metric and are very close in dimension to familiar customary fast
eners in the inch system. It is important to note that, during any
vehicle maintenance procedures, replacement fasteners must
have the same measurements and strength as those removed,
whether metric or customary. (Num ers on the heads of metric
olts and on surfaces of metric nuts indicate their strength.
Customary olts use radial lines for this purpose, while most
customary nuts do not have strength markings.) Mismatched or
incorrect fasteners can result in vehicle damage or malfunction, or
possi ly personal injury. Therefore, fasteners removed from the
vehicle should e saved for re-use in the same locations whenever
possi le. Where the fasteners are not satisfactory for re-use, care
should e taken to select a replacement that matches the original.
For information and assistance, see your dealer.
GENERAL INFORMATION
General Information
Maintenance and Lubrication
HEATING AND AIR CONDITIONING
Heating and Ventilation
Air Conditioning
FRAME AND BUMPERS
Frame and Body Mounts
Bumpers
heet Metal
Body
STEERING, SUSPENSION, WHEELS
AND TIRES
Front Alignment
teering Linkage
Manual teering
Power teering
teering Column
Front uspension
Rear uspension
Wheel and Tires
AXLEPropeller haft and Universal Joint
Rear Axle
Front Wheel Drive
BRAKES
ENGINE
Engine Mechanical
In-Line 6
mall Block
Mark IV
5.7L(Z) 350 Diesel
Engine Cooling
Fuel ystem - Diagnosis
Model 1ME
Model 2 E
Model M2MC
Model M4MC
Fuel upply
Engine Electrical
Emission Control ystems
Engine Exhaust
TRANSMISSION
Automatic
Manual
Clutch
Transfer Case
ELECTRICAL — BODY AND CHASSIS
Lamps and Lighting
Electrical and Wiring
Instrument Panel and Gages
ACCESSORIES
METRIC AND FASTENER INFORMATION
INDEX
OA
OB
1A
IB
2A
2B
2C
2D
3A
3B1
3B2
3B3
3B4
3C
3D
3E
4A
4B
4C
A
A1
A4
A5
A
B
C
C1
C2
C3
C4
C5
D
E
F
7A
7B
7C
7E
8A
8B
8C
10
11
© 1979 General Motors Corporation Printed in U. .A.

GENERAL INFORMATION OA-1
SE TION OA
GENERAL INFORMATION
ONTENTS OF THIS SE TION
General................................................................................................... . 0-1
Vehicle Identification Number ............................................................ . 0-1
Service Parts Identification Sticker..................................................... . 0-1
Vehicle Loading .................................................................................... . 0-1
Engine ode Number........................................................................... . 0-1
Unit and Serial Number Locations..................................................... . 0-3
GENERAL
Information to identify the vehicle and vehicle
components appears in this section. Detailed specifications
on major units are given at the end of each respective section
in this manual.
VEHI LE IDENTIFI ATION NUMBER (VIN)
This is the legal identification of the vehicle. It appears
on a plate which is attached to the left top of the instrument
panel on K and G truck and can be easily seen through
the windshield from outside the vehicle (fig. OA-1). On P10-
20-30 models, the plate is attached to the front of the dash
and toe panel to the left of steering column (fig. 0A-2). The
VIN also appears on the Vehicle ertificates of Title and
Registration.
SERVI E PARTS IDENTIFI ATION STI KER
The Service Parts Identification Sticker (fig. 0A-6) is
provided on all Truck models. On and K models, the
identification sticker be located on the inside of the glove
box door or on G model, the sticker will be located on an
inner hood panel surface. On P models, the sticker is located
on a inner body panel.
OCCL24AF153278] O
ENGINE ODE TYPI AL VIN
The plate lists the vehicle identification number,
wheelbase, and all Production options or Special Equipment
on the vehicle when it was shipped from the factory
including paint information. ALWAYS REFER TO
THIS INFORMATION WHEN ORDERING PARTS.
VEHI LE LOADING
Vehicle loading must be controlled so weights do not
exceed the numbers shown on the Vehicle Identification
Number and/or Rating Plate for the vehicle.
A typical example of a truck in a loaded condition is
shown in Figure 0A-7. Note that the axle or GVW
capabilities are not exceeded.
ENGINE ODE NUMBER
The engine code number indicates manufacturing
plant, month and day of manufacture, and transmission
type. A typical engine number would be F1210TTBB, which
would breakdown thus:
F - Manufacturing Plant (F-Flint, T-Tonawanda)
12 - Month of Manufacture (December)
10 - Day of Manufacture (tenth)
T - Truck
TBB - Transmission and engine type
oMFD. BY GENERAL MOTORS CORPORATION
G V W R f ^ ^ l
GAWR F R O N T ^ ^ ^ GAWR REAR
VIN
o
INFLATION DATA FOR TIRES FURNISHED WITH VEHICLE
SHOWN ON VEHICLE CERTIFICATIO N LABEL
WARRANTY VOIDED If LOADED IN EXCESS OF RATINGS
SEE OWNERS MANUAL FOR OTHER LOADING AND INFLATION DATA O
EXAMPLE ONLY
Fig. 0A-1-Vehicle Identification Number Location ( K and G) Fig. OA-2-V.I.N. Rating Plate (P Model)
LIGHT TRUCK SERVICE MANUAL

OA-2 GENERAL INFORMATION
LIGHT DUTY TRU K
(EX EPT EL AMINO)
VIN SYSTEM IDENTIFI ATION
D13AF100007
DIVISION
- hevrolet
T-GM
HASSIS TYPE
conventional ab
Ghevy Van & Sport Van
onventional ab 4 x 4
PForward ontrol
ODE
ENGINE
DISPLA EMENT TYPE ARB.
D 4.1 L 250 c d L62B
G5.0L 305 c d V82B
L5.7L 350 c d V84B
M5.7L 350 c d V84B
P 5.7L 350 c dV82B
R6.6L400 c d V84B
S7.4L 454 c dV84B
T 4.8 L 292 c d L61B
W7.4L 454 c dV84B
X6.6L 400 c d V84B
z5.7L 350 c d V8Diesel
PLANT SEQUENTIAL NUMBER
ASSEMBLY PLANT
“A' GMAD-Lakewood GA.
"B' GMAD-Baltimore MD.
"F' HEVROLET-Flint Ml.
"J" GMAD-Janesville Wl.
"S' GMAD-St. Louis MO.
"T GMAD-Fremont A.
"O GM Truck-Pontiac Ml.
“ V GM of anada-Oshawa Ont.
"3' HEVROLET-Detroit Ml.
“4'GM of anada-Scarborough Ont.
GMAD-Lordstown OH.
MODEL YEAR
A for 1980
BODY STYLE
2 hassis owl 81 Forward ontrol hassis
3 hassis ab
4 ab & Pick-Up Box or Hi- ube Van
5 hevy Van & Step Van
6 Sport Van & Suburban
7 Motor Home hassis
8 Blazer
MODEL
1-1/2 Ton
2-3/4 Ton
3-1 Ton
4-1/2 Ton (W/HDSusp)
Fig. 0A-3-Vehicle Identification Number
LIGHT TRUCK SERVICE MANUAL

GENERAL INFORMATION OA-3
IMPORTANT: RETAIN THIS PLATE AS A PERMANENT RECORD
Fig. 0A-4- ervice Parts Identification Plate
UNIT AND SERIAL NUMBER LO ATIONS
For the convenience of service technicians and
engineers when writing up certain business papers such as
Warranty Reports, Product Information Reports, or
reporting product failures in any way, the location of the
various unit numbers have been indicated. These unit
numbers and their prefix or suffix are necessary on these
papers for various reasons - such as accounting, follow-up
on production, etc.
The prefixes on certain units identify the plant in which
the unit was manufactured and thereby -permits proper
follow-up of the plant involved to get corrections made
when necessary.
Fig. 0A-5--Typical Vehicle Loading Condition
Always include the prefix in the number.
Axles
hevrolet Built
• On 10 Series, the ode is stamped on Top of Right
Rear Axle Tube.
• On 20-30 Series, the ode is stamped on Top of the
Right Rear Axle Tube.
Dana Built
• On Front Axles, code is stamped on Top Rear of Left
Axle Tube.
• On Rear Axles, code is stamped on Rear Surface of
Right Axle Tube.
Transmissions (Fig. OA-6)
• On 3-Speed Transmissions (except Tremec), the Unit
Number is located on Lower Left Side of ase Just Below
over.
• On Tremec Transmissions, Unit Number is located
on Upper Left Attachment ase (Top Side).
• On Muncie 4-Speeds, Unit Number is located on
Rear Face of ase below Retainer.
• On New Process 205 model 4-wheel drive transfer
case, a build date is on tag attached to front face of transfer
case.• On Automatic 350 Transmission, Unit Number is
Located on Right Rear Vertical Surface of Oil Pan.
• On the Automatic 400 Transmission, Serial Number
is Located on the Light Blue Plate on the Right Side of the
Transmission.
Engines (Fig. OA-7)
• 6- ylinder Engine Unit Number Located on Pad at
Right Hand Side of ylinder Block at Rear of Distributor.
• 8- ylinder Gasoline Engine ode is (305, 350, 400
ID) Located on Pad immediately forward of right hand
cylinder head.
• 8- ylinder Gasoline Engine (454 ID) ode is
located on a pad of the front top center of the engine block
immediately forward of the inlet manifold.
• 8- ylinder Diesel Engine ode is on a label located
on rear face of the left valve cover.
Generators
Generator Unit Serial Number is located on the Drive
End Frame Below the Part Number.
Batteries
Battery ode Number is Located on ell over Top
of Battery.
LOADED-MAXIMUM GVWR: 4900-LBS.
FRONT GAWR: 2944 LBS. REAR GAWR: 2944 LBS.
* Front Curb 2219 lbs.
Front Cargo &
Pass. Load 284 lbs.
2503 lbs.
'Rear Curb 1003 lbs.
Rear Cargo &
Pass. Load 1394 lbs.
2397 lbs.
TOTAL WEIGHT AT GROUND: 4900 lbs.
Curb weight equals the weight of the vehicle without driver,
passenger or cargo, but including fuel and coolant.
LIGHT TRUCK SERVICE MANUAL

OA-4 GENERAL INFORMATION
PRIMARY V.I.N.
LOCATION (Ml 5 SECONDARY V.I.N . LOCATION
To be used only when
suitable for stamping
fW'D ^
PRIMARY V.I.N. LOCATION (MCI
V.I.N . LOCATION (M20
MANUAL
VIEW
PRIMARY V.I.N .
LOCATION (MV4 or M38
SECONDARY V.I.N . LOCATION
To be used only when
primary locationis not
suitable for stamping
V.I.N . LOCATION (OPTIONAL (M40
0
VIEW
V.I.N . LOCATION
(OPTIONAL (M40
AUTOMATI
Fig. 0A-6-Transmission V.I.N. Location
Starters
Starter Serial Number and Production Date are
Stamped on Outer ase, Toward Rear.
DISTRIBUTOR PAD
ENGINE V .I.N .
(OPTIONAL
V8 ENGINE — DIESEL
ENGINE
CASE PAD
ENGINE
V .I.N .
L6 ENGINE
ENGINE V .I.N . #
(OPTIONAL
ENGINE V.I.N .
ENGINE
Fig. 0A-7-Engine V.I.N. Location
LIGHT TRUCK SERVICE MANUAL

MAINTENAN E AND LUBRI ATION OB-1
SE TION OB
MAINTENAN E AND LUBRI ATION
ONTENTS
General.............................................................................................. . OB-1
Maintenance Schedule..................................................................... . OB-2
Lubrication and General Maintenance ....................................... .. OB-4
Safety Maintenance........................................................................ .. OB-14
Emission ontrol Maintenance.................................................... .. OB-15
Specifications .................................................................................... .. OB-16
Recommended Fluids and Lubricants ........................................ .. OB-16
Fluid apacities.............................................................................. .. 0B-17
GENERAL
The maintenance schedule for a gasoline engine follows
two formats, Light Duty Emissions and Heavy Duty
Emissions (Fig. OB-1 and OB-2). A separate vehicle
maintenance schedule is provided for those vehicles with a
V-8 diesel engine (Fig. OB-3).
The maintenance schedule is provided in the glove box
with the vehicle.
LIGHT DUTY TRUCK SERVICE MANUAL

OB-2 MAINTENAN E AND LUBRI ATION
VEHI LE MAINTENAN E S HEDULE
GASOLINE ENGINE - LIGHT DUTY EMISSIONS
When To Perform Services
(Months or Miles (km)
Whichever Occurs First Item
No. Services
SE TION A — Lubrication and General Maintenance
Every 12 Months or 7,500 Miles (12 000 km) A-1 A Fluid Levels Check
A-2 Clutch Pedal Free Travel Check/Adjust.
A-3 *Engine Oil Change
ee Explanation
A-4 *Oil Filter Change
A-5 AChassis Lubrication
A-6 Front Wheel Drive
A-7 Tire Rotation
A-8 Rear Axle Lubrication
Every 12 Months or 15,000 Miles (24 000 km) A-9 *Cooling ystem Check — ee Explanation
Every 30,000 Miles (48 000 km) A-10 Wheel Bearing Repack
A-11 Manual teering Gear eals Check
A-12 Clutch Cross haft Lubrication
Every 100,000 Miles (160 000 km) A-13 Auto. Trans. Fluid & Filter Change
SE TION B — Safety Maintenance
Every 12 Months or 7,500 Miles (12 000 km)
6-1 Owner afety Checks
B-2 Tire, Wheel and Disc Brake Check
B-3 * Exhaust ystem Check
B-4 uspension and teering Check
B-5 Brake and Power teering Check
Every 12 Months or 15,000 Miles (24 000 km)
B-6 *Drive Belt Check
B-7 Drum Brake and Parking Brake Check
B-8 Throttle Linkage Check
B-9 Bumper Check
B-10 *Fuel Cap, Tank and Lines Check
SE TION — Emission ontrol Maintenance Schedule 1
At First 6 Months or 7,500 Miles (12 000 km) —
Then at 18 Month/22,500 Mile (36 000 km)
C-1 Thermo. Controlled Air Cleaner Check
C-2 Carburetor Choke Check
C-3 Engine Idle peed Adjustment
C-4 EFE ystem Check
C-5 Carburetor Mounting Torque
C-6 Vacuum Advance ystem & Hoses Check
Every 15,000 Miles (24 000 km) C-7 Fuel Filter Replacement
C-8 PCV ystem Check
PCV Valve & Filter ervice
Every 22,500 Miles (36 000 km)
C-9 park Plug Wires Check
C-10 Idle top olenoid and/or Dashpot Check
C-11 park Plug Replacement
C-12 Engine Timing Adjust. & Distrib. Check
C-13 Carburetor Vacuum Break Check
Every 30,000 Miles (48 000 km) C-14 Air Cleaner Element Replacement
C-15 EC ystem Check & Filter Replacement
SE TION — Emission ontrol Maintenance Schedule II
At first 6 Months or 7,500 Miles (12 000 km) —
Then 24-Month 30,000-Mile (48 000 km),
Except C-2 and C-6, Which Require ervice
at 45,000 Miles (72 000 km)
C-1 Thermo. Controlled Air Cleaner Check
C-2 Carburetor Choke & Hoses Check
C-3 Engine Idle peed Adjustment
C-4 EFE ystem Check
C-5 Carburetor Mounting Torque
C-6 Vacuum Advance ystem & Hoses Check
Every 15,000 Miles (24 000 km) C-7 Fuel Filter Replacement
C-8 PCV ystem Check
PCV Valve & Filter ervice
C-9 park Plug Wires Check
Every 30,000 Miles (48 000 km)
I
C-10 Idle top olenoid and/or Dashpot Check
C-11 park Plug Replacement
C-12 Engine Timing Adjust. & Distrib. Check
C-13 Carburetor Vacuum Break Check (1)
C-14 Air Cleaner Element Replacement
C-1 5 EC ystem Check & Filter Replacement
A Also A afety ervice *Also An Emission Control ervice (1) Applies only to GM Engine Family 08Y2A
Fig. 0B-1--Maintenance chedule - Gasoline - Light Duty Emissions
LIGHT DUTY TRUCK SERVICE MANUAL

MAINTENAN E AND LUBRI ATION OB-3
VEHI LE MAINTENAN E S HEDULE
GASOLINE ENGINE - HEAVY DUTY EMISSIONS
When To Perform Services
(Months or Miles/km, Whichever
Occurs First) Item
No. Services
(For Details, See Numbered Paragraphs)
SE TION A — Lubrication and General Maintenance
Every 4 months or 6,000 miles (9 600 km) A-1 •Fluid Levels Check
A-2 Clutch Pedal Free Travel Check/Adjust
A-3 *Engine Oil Change
A-5 •Chassis Lubrication
A-6 Front Wheel Drive
ee Explanation A-4 *Engine Oil Filter Change
A-7 Tire Rotation
A-8 Rear Axle Lubrication
A-10 Wheel Bearings Repack
Every 12 months or 12,000 miles (19 200 km) A-9 Cooling ystem Check
Every 24,000 miles (38 400 km) A-13 Auto. Trans. Fluid & Filter Change
Every 36,000 miles (57 600 km) A-11 Manual teering Gear Check
A-12 Clutch Cross haft Lubrication
SE TION B — Safety Maintenance
Every 4 months or 6,000 miles (9 600 km) B-1 Owner afety Checks
B-2 Tire, Wheel and Disc Brake Check
B-3 Exhaust ystem Check
B-4 uspension and teering Check
B-5 Brakes and Power teering Check
Every 12,000 miles (19 200 km) B-6 *Engine Drive Belts Check
Every 12 months or 12,000 miles (19 200 km) B-7 Drum Brakes and Parking Brake Check
B-8 Throttle Linkage Check
B-9 Bumpers
Every 24 months or 24,000 miles (38 400 km) B-10 *Fuel Cap, Lines and Tank Check
SE TION — Emission ontrol Maintenance
At 1st 4 months or 6,000 miles (9 600 km) — then
at 12 month/12,000 mile (19 200 km) intervals C-3 Engine Idle peed Adjustment
C-10 Idle top olenoid Check
Every 12,000 miles (19 200 km) C-9/11 park Plug Wire Check & Plug Replacement
C-12 Engine Timing Adjust. & Distributor Check
C-14 Air Cleaner Element Replacement
Every 12 months or 12,000 miles (19 200 km) C-5 Carburetor Mounting Torque
C-1 Thermo. Controlled Air Cleaner Check
C-17 Manifold Heat Valve Check
C-7 Carburetor Fuel Filter Replacement
C-18 Throttle Return Control
C-8 PCV ystem Check — PCV Valve & Filter ervice
Every 24 months or 24,000 miles (38 400 km) C-15 EC ystem Check & Filter Replacement
C-16 Engine Idle Mixture Adjust (4.8 L. L-6 only)
C-4 EFE ystem Check
C-6 Vacuum Advance ystem Check
C-2 Carburetor Choke Check
•Also A afety ervice * Also An Emission Control ervice
Fig. 0B-2--Maintenance chedule-Gasoline - Heavy Duty Emissions
LIGHT DUTY TRUCK SERVICE MANUAL

OB-4 MAINTENAN E AND LUBRI ATION
VEHI LE MAINTENAN E S HEDULE
DIESEL-FUELED VEHI LE
When To Perform Services
(Months or Miles, Whichever Occurs First)
Item
No.
Services
(For Details, See Numbered Paragraphs)
SE TION A — Lubrication and General Maintenance
Every 3,000 Miles (4 800 km) A-3 * Engine Oil hange
A-6 * Oil Filter hange
Every 6,000 Miles (9 600 km) A-4 • hassis Lubrication
A-1 • Fluid Levels heck
See Explanation A-8 Rear Axle Lubricant heck
A-7 Tire Rotation
Every 12 Months or 12,000 Miles (19 200 km) A-10 * ooling System heck
Every 15,000 Miles (24 000 km) A-9 Wheel Bearings Repack
Every 30,000 Miles (48 000 km) A-11 Manual Steering Gear heck
Every 100,000 Miles (160 000 km) A-13 Auto Trans. Fluid and Filter hange
SE TION B — Safety Maintenance
Every 12 Months or 6,000 Miles (9 600 km)
B-1 Owner Safety hecks
B-2 Tire, Wheels and Disc Brake heck
B-3 Exhaust System heck
B-4 Suspension and Steering heck
B-5 Brakes and Power Steering heck
B-6 * Drive Belt heck
Every 12 Months or 15,000 Miles (24 000 km)
B-7 Drum Brakes and Parking Brake heck
B-8 Throttle Linkage heck
B-9 Bumper heck
SE TION — Emissions ontrol Maintenance
Every 15,000 Miles (24 000 km) -7 Fuel Filter Replacement
Every 6,000 Miles (9 600 km) -19 rankcase Ventilation System
At First 3,000 Miles (4 800 km) Then at 30,000 Mile
(48 000 km) Intervals -3 Engine Idle Speeds Adjust
Every 30,000 Miles (48 000 km) -14 Air leaner Element Replacement
• Also a Safety Service * Also an Emission ontrol Service
Fig. 0B-3~Maintenance chedule - Diesel
MAINTENAN E S HEDULE
This is an explanation of the service listed in the
Vehicle Maintenance Schedule.
NORMAL VEHI LE USE-The maintenance
instructions contained in the maintenance schedule are
based on the assumption that the vehicle will be used as
designed:
• To carry passengers and cargo within the limitations
indicated on the Tire Placard located on the edge of the
driver’s door,
• on reasonable road surfaces within legal operating
limits,
• on a daily basis, as a general rule, for at least several
miles (km), and
• On unleaded gasoline (gasoline light duty emission
only).
Unusual operating conditions will require more
frequent vehicle maintenance as specified in the respective
sections.
SE TION A
LUBE & GENERAL MAINTENAN E
A-1 Fluid Levels
heck battery and the following fluid levels:
LIGHT DUTY TRUCK SERVICE MANUAL

MAINTENAN E AND LUBRI ATION OB-5
Battery are
The original equipment battery (two batteries on diesel
engine) needs no periodic maintenance. Its top is
permanently sealed (except for two small vent holes) and
has no filler caps. Water will never have to be added.
The hydrometer (test indicator) in the top of the
battery provides information for testing purposes only. See
Section 6D for battery test procedures.
Jump Starting
AUTION: The instructions below must
be followed exactly or personal injury
(particularly to eyes) or property damage
may result from battery explosion,
battery acid, or electrical (short circuit)
burns.
• To reduce the likelihood of sparks (and thus of an
explosion), and of electrical burns, be sure the jumper cables
do not have loose or missing insulation.
• THE MAJOR SAFETY PRE AUTION WHEN
JUMP STARTING IS TO MAKE THE FINAL
ONNE TION TO GROUND (A SOLID
STATIONARY METALLI OBJE T) ON THE
ENGINE AT SOME DISTAN E FROM THE
BATTERY. THIS HELPS REDU E THE HAN E OF
AN EXPLOSION DUE TO SPARKS.
• To lessen the chance of an explosion, never expose
the battery to open flames or electric sparks. Also do not
smoke near the battery. Batteries give off a gas which is
flammable and explosive.
• To lessen the risk of injury in case an explosion does
occur, wear eye protection or shield your eyes when
working near any battery. Do not lean over a battery.
• Do not allow battery fluid to contact eyes, skin,
fabrics, or painted, surfaces because battery fluid is a
corrosive acid. Flush any contacted area with water
immediately and thoroughly. Also get medical
help if eyes are affected .
• To lessen the risk of a short circuit, remove rings,
metal watch bands and other metal jewelry. Also do not
allow metal tools to contact at the same time the positive
battery terminal (or any metal connected to this terminal)
and any other metal on the vehicle.
Make certain when attaching the jumper cable clamps
to the positive terminals of the batteries that neither clamp
contacts any other metal.
• The vehicle has a 12 volt battery and a negative
ground electrical system. Make sure that the other vehicle
also has a 12 volt battery and that the negative terminal is
grounded (attached to a metal part of the vehicle). Its
owner’s manual may give you that information. If unsure
of the other vehicle’s voltage (or if the voltage and ground
on the other vehicle are different from your vehicle), do not
try to jump start as personal injury or severe damage to
electrical and electronic parts may result.
• If the discharged battery has filler caps, check the
fluid level. (Do not check with an open flame and do not
smoke). Add clear drinking water to the proper level if low,
and replace the caps before jump starting.
Fig. 0B-4-Power teering Filler Cap
Brake Master ylinder
(Also a Safety Service)
heck fluid level in each reservoir and maintain 1/4"
below lowest edge of each filler opening with Delco Supreme
No. 11 or DOT-3 hydraulic brake fluid, or equivalent.
A low fluid level in the brake master cylinder can
indicate worn disc brake pads, and should be checked
accordingly.
Hydro-boost Brake System Hydraulic Pump
1. Vehicles Equipped With Power Steering.
• On vehicles equipped with power steering, the power
steering pump is also used as the Hydro-boost pump. See
section on power steering system when checking fluid level
or adding fluid.
2. Vehicles Equipped With Manual Steering.
• The Hydro-boost pump installed in vehicles equipped
with manual steering uses power steering fluid. See section
on power steering system when checking fluid level or
adding fluid.
NOTI E: Power steering fluid and brake fluid cannot
be mixed, since seat damage may result.
Power Steering System
(Also a Safety Service)
heck the fluid level in the power steering pump at
each oil change and add GM Power Steering FLuid (GM
1050017) or equivalent as needed (Fig. OB-4):
• If fluid is warmed up (about 150°F or 66° -hot to
the touch), it should be between "Hot" and " old" marks
on the filler cap indcator.
• If cool (about 70°F or 21° ), fluid should be between
"Add" and " old" marks.
Fluid does not need periodic changing.
Rear Axle (Standard) Lubricant
heck lubricant level. Add lubricant, if necessary, to
fill to level of filler plug hole. Use SAE 80W GL-5 or SAE
80W-90 GL-5 or GM 1052271/1052272 gear lubricant. For
those vehicles driven in anada, use SAE 80W GL-5 gear
LIGHT DUTY TRUCK SERVICE MANUAL

OB-6 MAINTENAN E AND LUBRI ATION
Fig. 0B-5~Automatic Transmission Dipstick
lubricant.
Rear Axle (Limited-Slip) Lubricant
heck lubricant level. Add lubricant, if necessary, to
fill to level of filler plug hole. Use gear lubricant GM
1052271/1052272 or equivalent.
Automatic Transmission Fluid
Use only automatic transmission fluid labeled
DEXRON®-II or equivalent.
heck the automatic transmission fluid level at each
engine oil change period. Overfilling can cause foaming and
loss of fluid. Transmission damage can result. Low fluid
level can cause slipping or loss of drive.
Automatic transmissions are often overfilled because
the fluid level is checked when the fluid is cold. When cold,
the dipstick shows that fluid should be added. However, the
low reading is normal, the level will rise as the fluid gets
warm. The fluid level will increase more than 3/4 inch
(19mm) as fluid warms up from 60°F to 180°F (16° to
82° ).
heck the transmission fluid level with the engine
running, the shift lever in "Park", and the vehicle level.
If the vehicle has just been driven for a long time at
high speed or in city traffic in hot weather, or if the vehicle
has been pulling a trailer, the correct fluid level cannot be
read. Wait until the fluid has cooled down (about 30
minutes).
Remove the dipstick. arefully touch the wet end of
the dipstick to find out if the fluid is cool, warm or hot. Wipe
it clean and push it back in until cap seats. Pull out the
dipstick and read the fluid level (fig. 0B-5).
• If it felt cool, about room temperature, the level
should be 1/8 to 3/8 inch (3 to 10mm) below the "Add"
mark. The dipstick has two dimples below the "Add" mark
to show this range.
• If it felt warm, the level should be close to the "Add"
mark (either above or below).
• If it was too hot to hold, the level should be at the
"Full" mark.
• It takes only one pint (0.5 liter) to raise level from
"Add" to "Full" with a hot transmission.
Manual Transmission Lubricant
heck lubricant level. Add lubricant, if necessary, to
fill to level of filler plug hole.
Use SAE 80W GL-5 or SAE 80W-90 GL-5 gear
lubricant. For those vehicles driven in anada, use SAE
80W GL-5 gear lubricant.
Windshield Washer Fluid
(Also a Safety Service)
Fill the washer jar only 3/4 full during the winter to
allow for expansion if the temperature should fall low
enough to freeze the solution.
• heck the washer fluid level regularly-do it often
when the weather is bad.
• Use a fluid such as GM Optikleen or equivalent to
help prevent freezing damage, and for better cleaning.
• Do not use radiator antifreeze in the windshield
washer; it could cause paint damage.
• In cold weather, warm the windshield with
the defrosters before using the washer--to help
prevent icing that may block the driver's vision.
ooling System are
Do not remove radiator cap to check coolant level.
Instead, check by looking at the "see through" coolant
recovery tank. Level should be at the "Full old" mark on
the recovery tank when the system is cold; and at the "Full
Hot" mark during engine operation. Add a 50/50 mixture
of a good quality ethylene glycol antifreeze and water to the
recovery tank when more coolant is needed. If frequent
additions are needed, cooling system.
NOTI E: If the proper quality antifreeze is used, there
is no need to add extra inhibitors or additives that claim
to improve the system. They may be harmful to the
proper operation of the system, and are an unnecessary
expense.
A-2 Manual Transmission lutch Adjustment
lutch adjustment should be checked and adjusted as
necessary to compensate for clutch facing wear. To check,
depress pedal by hand until resistance is felt. Free travel
should be approximately one to one and a half inches; if very
little or no free travel is evident, clutch adjustment is
required.
A-3 & A-6 Engine Oil and Filter
(Also an Emission Control Service)
Engine Oil and Filter Recommendations
Gasoline
• Engine oils are labeled on the containers with various
API (American Petroleum Institute) designations of
quality. Use engine oils that are labeled SE, SF or SE/ .
Do not use oils labeled only SA, SB, S , SD, A, B,
or D; or oils with the combination label SE and D (SE/
D).• Use only SE or SF quality engine oils (see markings
on containers).
• The oil and filter change intervals for the engine is
based on the use of SE-quality or SF-quality oils and high
quality filters. Using oils other than SE-quality or SF-
quality oils, or oil change intervals longer than listed, could
reduce engine life and might affect warranty.
• The engine was filled with an SE or SF quality engine
oil when it was built. You do not have to change this oil
before the suggested change period.
• hange oil each 7,500 miles (12 000 km) or once a
year for light duty emissions service, each 6,000 miles (9 600
km) or 4 months for heavy duty emissions service,
LIGHT DUTY TRUCK SERVICE MANUAL

MAINTENAN E AND LUBRI ATION OB-7
whichever occurs first.
• hange oil filter:
Light Duty Emissions- Replace at the first oil
change and then every second oil change if mileage 7,500
miles (12 000 km) determines oil change. If time (12
months) determines oil change, or you change the oil at
3,000 miles (4 800 km) or 3 months, replace filter at each
oil change.
Heavy Duty Emissions- Replace at the first oil
change, and then every second oil change if mileage 6,000
miles (9 600 km) determines oil change. If time (4 months)
determines oil change, or you change the oil at 3,000 miles
(4 800 km) or 2 months, replace filter at each oil change.
• hange oil and filter each 3,000 miles (4 800 km) or
3 months (light duty emissions) or 2 months (heavy duty
emission service) if:
• Driving in dusty areas
• Pulling a trailer
• Frequent idling or idling for long periods
• Driving 4 miles (6 km) or less in freezing weather,
or other short trips in cold weather, where the engine does
not thoroughly warm up.
• After driving in a dust storm, change the oil and filter
as soon as possible.
Engine Oil Additives The engine should not need
these extra engine oil helpers or additives if SE quality
engine oil is used and changed as suggested. If you think
your engine has an oil related problem, refer to Section 6A.
Diesel Engine
Use ONLY engine oils labeled with the A.P.I.
(American Petroleum Institute) designations SE and .
Do not use any other type of oil. The A.P.I. designations
are listed somewhere on the oil can, usually on the top or
label. The A.P.I. has several designations, such as: S , SD,
SE, B, , D.
Several Different designations may appear on the can.
Be sure the oil used has both the SE and the
designations, regardless of the order in which they appear
on the oil can. Do not use an oil if the designation D
appears anywhere on the oil can. Using any type of oil other
than SE/ may affect warranty.
NOTI E: Do NOT use engine oils labeled only SE or
only . These oils will not give the protection and
lubrication of diesel engine needs. When reading the
can, be sure not to confuse the SE designation with the
letters "SAE", which may also appear on the can.
• It is VERY IMPORTANT to change the oil and
filter every 3,000 miles (4 800 km). Because of the way a
diesel engine operates, contaminants build up in the oil
faster than in a gasoline engine which can cause engine wear
and/or damage.
• hange the oil and filter soon after driving in a dust
storm.
• Single viscosity grade oils (such as SAE 30) are more
satisfactory than multi-viscosity oils (such as SAE 10W-30)
for sustained high-speed driving.
The oil and filter change intervals for a diesel engine
are based on the use of SE/ quality oils and quality oil
filters. Use of oils other than SE/ or oil and filter change
NOTI E: Do not use AE 5W-20 oils for continuous
high-speed driving.
Fig. OB-6--OM Viscosity Chart (Gasoline)
intervals longer than 3,000 miles (4 800 km) could reduce
engine life and may affect warranty.
The diesel engine was filled with a quality engine oil
when it was built. You do not have to change the oil before
the recommended change interval. Keep in mind the engine
may use more oil when it is new. heck the oil level more
often when the engine is new.
Engine Oil Additives Do not use any supplemental
additives. Using oil additives may cause engine damage and
may affect warranty. If you think the engine has an oil
related problem, see Section 6A.
Oil Viscosity (Figs. OB-6 and 7) # i
Engine oil viscosity (thicknesS^has an effect on fuel
economy. Lower viscosity engine oils can provide increased
fuel economy; however, higher temperature weather
conditions require higher viscosity engine oils for
satisfactory lubrication. Figures 0B-6 and 0B-7 lists the
engine oil viscosities that will provide the best balance of
fuel economy, engine life, and oil economy.
hecking Oil Level r
• Warm- The best time to check the engine oil level
is when the oil is warm, such as during a fuel stop. First,
allow about 5 minutes for the oil to drain back to the oil
pan. Then pull the dipstick out, wipe it clean, and push it
USE THESE SAE VISCOSITY GRADES (SE/CC)
«
SAE 30
SAE 10W-30
F -20
+020 32 40 0 80 100
-t—
C -30 -20 -10 0 10 20 30 40
* FOR S USTA IN ED HIGH SPEED D R IV IN G ABOVE
32°F (0° ) USE SAE 30 G R A DE.
TE M PE RATU RE RANGE YOU EXPE T BEFO RE N E XT OIL HANG E
Fig. OB-7--OM Viscosity Chart (Diesel)
LIGHT DUTY TRUCK SERVICE MANUAL

OB-8 MAINTENAN E AND LUBRI ATION
back down all the way. Now pull the dipstick out and look
at the oil level on the dipstick. Some dipsticks are marked
with "Add" and "Full" lines. Others are marked "Add 1
Qt" and "Operating Range". In all cases, keep the oil
level above the "Add" line . Push the dipstick back
down all the way after taking the reading. Add oil if needed.
• old - If you check the oil level when the oil is cold,
do not run the engine first. The cold oil will not drain back
to the pan fast enough to give a true oil level.
A-4 hassis Lubrication (Figs. OB-8 and 9)
Large fluid loss in any of these units may point out a
problem. Repair these problems promptly.
Lubricate the following system or units:
Steering Linkage and Suspension
(Also a Safety Service)
Lubrication Intervals
a. On 20, G30 and P20, lubricate every 4 months or
6,000 miles (9 600 km).
b. On all other vehicles, lubricate every 12 months or
7,500 miles (12 000 km).
Maintain correct front end alignment to provide easy
steering, longer tire life, and driving stability.
heck control arm bushings and ball joints for wear.
Lubricate tie rods, upper and lower control arms, and
ball joints at fittings with water resistant EP chassis
lubricant which meets General Motors Specification GM
6031M. Lubricate every 3 months (Light Duty), 2 months
(Heavy Duty and Diesel), or 3,000 miles (4 800 km)
whichever occurs first, under the following conditions:
• Driving in dusty or muddy conditions.
• Extensive off-road use.
Ball joints must be at 10°F (-12° ) or more before
lubricating.
Transmission Shift Linkage
(Manual and Automatic)
(Also a Safety Service)
Lubricate shift linkage and manual transmission floor
controls lever contacting faces with water resistant EP
chassis lubricant which meets GM specification 6031M.
Hood Latches
Lubricate hood latch assembly and hood hinge
assembly as follows:
1. Wipe off any accumulation of dirt or contamination
on latch parts.
2. Apply Lubriplate or equivalent to latch pilot bolts
and latch locking plate.
3. Apply light engine oil to all pivot points in release
mechanism, as well as primary and secondary latch
mechanisms.
4. Lubricate hood hinges.
5. Make hood hinge and latch mechanism functional
check to assure the assembly is working correctly.
Door Lock ylinder
Use WD-40 or equivalent spray lubricant as necessary
for free operation.
Gas Tank Filler Door Hinge
lean area of dirt and old lubricant. Apply a few drops
of engine oil to friction point of door hinge. Work door
several times and wipe off excess lubricant.
Door Hinge Assembly
Wipe off dirt and apply a thin coat of engine oil. Open
and close door several times to insure that the oil has
worked in effectively.
Door Jam Switch
Apply a thin coat of lubriplate or equivalent to end of
surface of switch plunger.
Parking Brake Pulley, able and Linkage
(Also a Safety Service)
Apply water resistant EP chassis lubricant which meets
GM specification 6031M, to parking brake cable at cable
guides and at all operating links and levers.
Accelerator Linkage
(Also a Safety Service)
Lubricate carburetor stud and carburetor lever and
accelerator pedal lever at support with engine oil.
Body Lubrication
See Body Service Manual for body lubrication.
A-5 Four Wheel Drive
Most lubrication recommendations and procedures for
four wheel drive-equipped vehicles are the same for
corresponding components of conventional drive vehicles.
In addition, the following items require lubrication
each 4 months or 6,000 miles (9 600 km).
Transfer ase
heck the transfer case level at the interval and if
necessary, add lubricant as follows:
onventional Four Wheel Drive- Add 10W-30 or
10W -40 engine oil to bring to level of filler plug hole.
Front Axle
The front axle should be checked at the interval and
refilled with SAE 80W-90 GL-5 gear lubricant when
necessary. With the differential at operating temperature fill
to the level of filler plug hole. If differential is cold, fill to
level of 1/2 inch below the filler plug hole.
Propeller Shaft Slip Joints
Propeller shaft slip joints should be lubricated at the
interval with water resistant EP hassis lubricant which
meets General Motors Specification GM 6031M.
onstant Velocity ( /V Joint)
A /V joint is located at the transfer case end of the
front propshaft and must be lubricated at the interval with
GM lubricated part no. 1052497 or equivalent. See Fig. 0B-
10 showing how the fitting may be lubricated from above
the /V joint, with a special adapter on the end of a flex
hose.
A-6 Oil Filter
Refer to item A-3 for oil filter recommendations.
LIGHT DUTY TRUCK SERVICE MANUAL

MAINTENAN E AND LUBRI ATION OB-9
1 Lower Control Arms 6 Wheel Bearings 11 Throttle Bell Crank — L-6
2 Upper Control Arms 7teering Gear 12 Carburetor Linkage - V-8
3Upper and Lower Control 8 Air Cleaner - Element 13 Brake and Clutch Pedal
Arm Ball Joints 9 Master Cylinder prings
4Intermediate teering 10 Transmission - Manual 14 Universal Joints
haft (PA10) - Automatic 15 Rear Axle
5Tie Rod Ends
FOUR WHEEL DRIVE MODELS
LUBRI ATION POINTS
1Air Cleaner 6Master Cylinder 11 Front and Rear Axle
2Control Linkage Points 7 Transmission - Manual 12 Drag Link
3Tie Rod Ends - Automatic 13 Brake and Clutch
4Wheel Bearings 8 Carburetor Linkage — V-8 Pedal prings
5teering Gear 9 Universal Joints 14 Transfer Case
10 Propeller haft lip Joints 15 Throttle Bell Crank - L-6
Fig. 0B-8-Lubrication Points (Conventional and Four Wheel Drive)
LIGHT DUTY TRUCK SERVICE MANUAL

OB-10 MAINTENAN E AND LUBRI ATION
LUBRI ATION POINTS
1 Control Arm Bushings and 5 Trans. Control haft 8Rear Axle
Ball Joints 6Air Cleaner - Element 9 Oil Filter
2Tie Rod Ends 7Transmission - Manual 10 Brake Master Cylinder
3 Wheel Bearings - Automatic 11 Parking Brake Linkage
4 teering Gear
Clutch Cross- haft
Fig. 0B-9-Lubrication Points (G Van)
A-7 Tires
Inspection and Rotation
Front and rear tires perform different jobs and can
wear differently depending on the types of roads driven,
driving habits, etc. To obtain maximum tire life inspect and
rotate tires regularly. (Fig. OB-11) If the truck is equipped
with tires having different load ratings between the front
and the rear, the tires should not be rotated front to rear.
Vehicle handling could be adversely affected and the tires
having the lower load rating could be overloaded.
AUTION: Before installing wheels,
remove any build up of corrosion on the
wheel mounting surface and brake drum
B 0 rB
a \ m
4 WHEEL
ROTATION
rflnrfri rS
LgjLflJ Lg
4 WHEEL
ROTATION
ROTATION - BIAS ROTATION - RADIAL
AND BIAS - BELTED
*Do not include "temporary use only" spare tire in rotation.
Fig. 0B-10-C/V Joint Lube Fitting Fig. OB-1 1-Tire Rotation
(K-10 & 20 MODELS) (K-30 MODELS)
LIGHT DUTY TRUCK SERVICE MANUAL