2003 CHEVROLET C/K oil

7-20
(39) = Air brake service:

Inspect brake lines and hoses for proper hook
-up,
binding, leaks, cracks, chafing, etc. Inspect drum
brake linings for wear or cracks. Inspect other brake
parts at each wheel, including drums, wheel
cylinders and piston heat shields, boots and wheel
speed sensor wiring. Check brake pedal for excessive
free play or travel (or every 6 months, whichever
occurs first) and have serviced if needed. Check
brakes more often if driving habits and conditions
result in frequent braking. Replace air dryer cartridge
only if excessive oil or moisture is present. A small
amount of oil in the system is normal and should not
be considered as a reason to replace the cartridge.

Test air lines for leaks; tighten as needed. Replace
compressor filter.

Inspect air parking brake chamber for leaks and
damage. Inspect lines and hoses for leaks, cracks,
chafing, etc. Also check all attachments for
tightness, wear or damage. Note: The spring brake
section of the rear brake diaphragms are
non
-serviceable.

Replace the air compressor filter element, mounted
on the air compressor. For remote air compressor
intake service, refer to engine air cleaner filter
replacement.
Remove, disassemble, clean and inspect the safety
valve, standard brake chamber, quick release valve,
quick release/double check valve combination,
parking brake control valve, double check valve,
pressure protection valve and alcohol injector.

Remove, disassemble and clean the application
valve; replace parts showing wear.

Remove, disassemble, clean and inspect the spring
brake control valve; replace rubber parts.
(40) = Clean and lubricate air brake automatic slack
adjuster. Check pushrod travel and auto adjustment
operation. Have serviced if needed.
(41) = Air brake chamber service: Check operation,
mounting, clamps and air lines and check for leaks.
(42) = Trailer brake hand control valve service: Check
operation; lubricate cam and follower.
(46) = Tighten the wheel stud nuts to the specified
torque values at 100 miles (160 km). Thereafter, tighten
them 1,000 miles (1 600 km) after each time the wheel
is removed. See ªTightening the Wheel Nutsº in
the Index.

7-21
Part B: Owner Checks and Services
Listed in this part are owner checks and services which
should be performed at the intervals specified to help
ensure the safety, dependability and emission control
performance of your vehicle.
For your safety and that of others, any of the
safety
-related components that may have been damaged
in an accident should be checked and any needed repairs
made before operating the vehicle.
At the minimum, these routine checks should be made
every 6 months or 6,000 miles (10 000 km), whichever
occurs first. Whenever repairs are needed, have them
completed before operating the vehicle.
At Each Fuel Fill
It is important for you or a service station attendant to
perform these underhood checks at each fuel fill.Engine Oil Level Check
Check the engine oil level and add the proper oil
if necessary. See ªEngine Oilº in the Index for
further details.
Engine Coolant Level Check
Check the engine coolant level and add DEX
-COOL

coolant mixture if necessary. See ªEngine Coolantº in
the Index for further details.
Windshield Washer Fluid Level Check
Check the windshield washer fluid level in the
windshield washer tank and add the proper fluid if
necessary. See ªWindshield Washer Fluidº in the Index
for further details.
Tire Inflation Check
Check tire inflation cold. Make sure tires are inflated to
the pressures specified on the GVW Rating label. See
ªLoading Your Vehicleº and ªTiresº in the Index for
further details.

7-22 At Least Twice a Year
Restraint System Check
Make sure the safety belt reminder light (if equipped)
and all your belts, buckles, latch plates, retractors and
anchorages are working properly. Look for any other
loose or damaged safety belt system parts. If you see
anything that might keep a safety belt system from
doing its job, have it repaired. Have any torn or frayed
safety belts replaced.
Wiper Blade Check
Inspect wiper blades for wear or cracking. Replace blade
inserts that appear worn or damaged or that streak or
miss areas of the windshield. Also see ªWiper Blades,
Cleaningº in the Index.Engine Air Cleaner Filter Restriction
Indicator Check
Your vehicle has an indicator located on the air cleaner
in the engine compartment that lets you know when the
air cleaner filter is dirty and needs to be changed. Check
indicator at least twice a year or when your engine oil is
changed, whichever occurs first. See ªEngine Air
Cleanerº in the Index for more information. Inspect your
air cleaner filter restriction indicator more often if the
vehicle is used in dusty areas.
Weatherstrip Lubrication
Silicone grease on weatherstrips will make them last
longer, seal better, and not stick or squeak. Apply
silicone grease with a clean cloth. During very cold,
damp weather more frequent application may be
required. See ªRecommended Fluids and Lubricantsº in
the Index.

7-23
Body Lubrication Service
Lubricate all exposed surfaces such as door checks, door
lock bolts, lock strike plates, door latches and dovetail
bumper wedges. Where oil holes are provided a dripless
oil can be used. The seat adjusters, seat track, door
weatherstrips and rubber cap bumpers should also be
lubricated.
Part C tells you what to use. More frequent lubrication
may be required when exposed to a corrosive
environment.
Parking Brake Check
Park on a fairly steep hill and hold the vehicle with the
parking brake only. This checks holding ability.Starter Switch Check
CAUTION:
When you are doing this check, the vehicle could
move suddenly. If it does, you or others could be
injured. Follow the steps below.
1. Before you start, be sure you have enough room
around the vehicle.
2. Firmly apply both the parking brake and the
regular brakes. See ªParking Brakeº in the Index
if necessary.
Do not use the accelerator pedal, and be ready to turn
off the engine immediately if it starts.
3. On automatic transmission vehicles, try to start the
engine in each gear. The starter should work only in
PARK (P), if equipped, or NEUTRAL (N). If the
starter works in any other position, your vehicle
needs service.

7-26
Fluid Leaks Check
Check for fuel, coolant, oil or other fluid leaks by
looking at the surface beneath the vehicle after it has
been parked for awhile.
Underbody Inspection
Corrosive materials used for ice, snow removal and dust
control can collect on the underbody. If these materials
are not removed, accelerated corrosion (rust) can occur
on underbody parts such as fuel lines, frame, floor pan
and exhaust system. At least every spring, flush these
materials from the underbody with plain water. Take
care to clean well any areas where mud and other debris
can collect. Sediment packed in closed areas of the
frame should be loosened before being flushed.
Engine Cover Check
Check that the cab's engine cover and seal (if equipped)
are not torn or damaged. Be sure that the cover is
clamped down firmly to the floor.At Least Once a Year
Key Lock Cylinders Service
Lubricate the key lock cylinders with the lubricant
specified in Part C.
Underbody Flushing Service
At least every spring, use plain water to flush any
corrosive materials from the underbody. Take care to
clean thoroughly any areas where mud and other debris
can collect.
Tractor Protection (Breakaway) Valve Check
On air brake models, remove, disassemble, clean and
inspect the tractor protection (breakaway) valve.

7-27
Part C: Recommended Fluids and
Lubricants
Fluids and lubricants identified below by name,
part number or specification may be obtained from
your dealer.
USAGE
FLUID/LUBRICANT
Engine Oil
(Gasoline
Engine)Engine oil with the American
Petroleum Institute Certified for
Gasoline Engines starburst symbol
of the proper viscosity. To
determine the preferred viscosity
for your vehicle's engine, see
ªEngine Oilº in the Index.
Engine Oil
(Caterpillar
Diesel Engine)See the Caterpillar
Operation &
Maintenance Manual for engine
oil recommendations.
USAGEFLUID/LUBRICANT
Engine Coolant
(Gasoline
Engine &
DURAMAX
Diesel)50/50 mixture of clean, drinkable
water and use only DEX
-COOL

Coolant. See ªEngine Coolantº in
the Index.
Engine Coolant
(Caterpillar
Diesel Engine)See the Caterpillar
Operation &
Maintenance Manual for engine
coolant recommendations.
Hydraulic Brake
SystemDelco Supreme 11
Brake Fluid
or equivalent DOT
-3 brake fluid.
Windshield
Washer SolventGM Optikleen
Washer Solvent
or equivalent.
Clutch Bearing
LubricantClutch Bearing Lubricant
(GM Part No. 12378484 or
equivalent NLGI #3 consistency).

7-28
USAGEFLUID/LUBRICANT
Exhaust Brake
Ball Joint Cap
LubricantHigh-Temperature Grease
(GM Part No. U.S. 1051344, in
Canada 903037, or equivalent) or
NLGI #3 consistency.
Power Steering
SystemDEXRON
-III Automatic
Transmission Fluid.
Manual
Transmission
(Except ZF
6
-Speed)
Synthetic Manual
Transmission Fluid
(GM Part No. U.S. 12345724,
in Canada 10953510).
Manual
Transmission
(ZF 6
-Speed)
TranSynd Synthetic
Transmission Fluid
(GM Part No. U.S. 12378515,
in Canada 88900701).
USAGEFLUID/LUBRICANT
Automatic
TransmissionSee the Allison Transmission
Operator's Manual for correct
transmission fluid.
Chassis
LubricationChassis Lubricant
(GM Part No. U.S. 12377985, in
Canada 88901242, or equivalent)
or lubricant meeting requirements
of NLGI # 2, Category LB
or GC
-LB.
Front Wheel
Bearing Grease
(Except Oil
Filled Hubs)Wheel bearing lubricant meeting
requirements of NLGI # 2,
Category GC or GC
-LB
(GM Part No. U.S. 1051344, in
Canada 993037, or equivalent).

7-29
USAGEFLUID/LUBRICANT
Front Wheel
Bearings with
Oil Filled HubsSAE 75W-90 Synthetic
Axle Lubricant for Medium
Duty Trucks (GM Part
No. U.S. 12345841, in
Canada 10953512, or equivalent).
Rear Axle and
Rear HubsSAE 75W-90 Synthetic
Axle Lubricant for Medium
Duty Trucks (GM Part
No. U.S. 12345841, in
Canada 10953512, or equivalent).
Rear Axle Shift
Motor LubricantRefrigerant Oil
(GM Part No. U.S. 5416939,
in Canada 10953496).
USAGEFLUID/LUBRICANT
Propshafts and
SplinesWheel bearing lubricant meeting
requirements of NLGI # 2,
Category GC or GC
-LB
(GM Part No. U.S. 1051344, in
Canada 993037, or equivalent).
Cab -- Door
LatchesMulti-Purpose
Lubricant, Superlube

(GM Part No. U.S. 12346241, in
Canada 10953474, or equivalent).
Weatherstrip
ConditioningDielectric Silicone Grease
(GM Part No. U.S. 12345579, in
Canada 1974984, or equivalent).
Weatherstrip
SqueaksSynthetic Grease with
Teflon, Superlube

(GM Part No. U.S. 12371287, in
Canada 10953437, or equivalent).