
5. Release the parking brake only after the vehicle
being towed is firmly attached to the tow vehicle.
6. Turn the ignition to LOCK.
If the tow vehicle will not be started or driven for
six weeks or more, remove the battery cable
from the negative terminal (post) of the battery to
prevent your battery from draining while towing.
All-Wheel-Drive Vehicles
Your vehicle was not designed to be towed with
two wheels on the ground. To properly tow these
vehicles, they should be placed on a platform trailer
with all four wheels off the ground.
Notice:Towing an all-wheel-drive vehicle with all
four wheels on the ground, or even with only two of
its wheels on the ground, will damage drivetrain
components. Do not tow an all-wheel-drive vehicle if
any of its wheels will be on the ground.
Towing a Trailer
{CAUTION:
If you do not use the correct equipment and
drive properly, you can lose control when you
pull a trailer. For example, if the trailer is too
heavy, the brakes may not work well — or even
at all. You and your passengers could be
seriously injured. Pull a trailer only if you have
followed all the steps in this section. Ask your
dealer for advice and information about towing
a trailer with your vehicle.
Notice:Pulling a trailer improperly can damage
your vehicle and result in costly repairs that would
not be covered by your warranty. Always follow
the instructions in this section and check with your
dealer for more information about towing a trailer
with your vehicle.
To identify the trailering capacity of your vehicle, you
should read the information in “Weight of the Trailer” that
appears later in this section.
4-37

When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes. If you turn your
engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a
few minutes before turning the engine off. If you do get
the overheat warning, seeEngine Overheating on
page 5-24.
Parking on Hills
{CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK (P) yet. Then turn your wheels into the curb if
facing downhill or into traffic if facing uphill.2. Have someone place chocks under the
trailer wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake and then shift to PARK (P).
5. Release the regular brakes.
When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
•start your engine,
•shift into a gear, and
•release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store
the chocks.
4-50

Maintenance When Trailer Towing
Your vehicle will need service more often when you’re
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission fluid (don’t overfill),
engine oil, axle lubricant, belt, cooling system and
brake system. Each of these is covered in this manual,
and the Index will help you find them quickly. If
you’re trailering, it’s a good idea to review these sections
before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Trailer Wiring Harness
The optional heavy-duty trailer wiring package includes
a seven-wire harness assembly at the rear of the
vehicle and a four-wire harness assembly under the left
hand side of the instrument panel. The seven-wire
harness assembly is taped together and located in a
frame pocket at the driver side rear left corner of
the frame. The seven-wire harness includes a 30-amp
feed wire. Both harnesses come without connectors and
should be wired by a qualified electrical technician.
The technician can use the following color code chart
when connecting the wiring harness to your trailer
and trailer brake controller.Seven-Wire Harness
•Light Green: Back-up lamps
•Brown: Parking lamps
•Yellow: Left stoplamp and turn signal
•Dark Green: Right stoplamp and turn signal
•Dark Blue: Use for electric trailer brakes
•Orange: Trailer accessory
•White (heavy gage): Ground wire
Four-Wire Harness (Trailer Brake Controller)
•Black: Ground
•Red/White Stripe: Fused Battery
•Dark Blue: Trailer Brake Feed
•Light Blue: Fused Stoplamp/CHMSL
4-51

Service............................................................5-3
Accessories and Modifications..........................5-3
California Proposition 65 Warning.....................5-4
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside of
Your Vehicle..............................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Specifications....................................5-5
California Fuel...............................................5-6
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-7
Filling the Tank..............................................5-8
Filling a Portable Fuel Container.....................5-10
Checking Things Under the Hood....................5-10
Hood Release..............................................5-11
Engine Compartment Overview.......................5-12
Engine Oil (Gasoline Engine)..........................5-13
Engine Oil Life System (Gasoline Engine)........5-16
Engine Air Cleaner/Filter................................5-17
Automatic Transmission Fluid.........................5-19
Engine Coolant.............................................5-21
Radiator Pressure Cap..................................5-24
Engine Overheating.......................................5-24Cooling System............................................5-26
Engine Fan Noise.........................................5-32
Power Steering Fluid.....................................5-32
Windshield Washer Fluid................................5-34
Brakes........................................................5-35
Battery........................................................5-38
Jump Starting...............................................5-39
All-Wheel Drive..............................................5-43
Rear Axle.......................................................5-44
Front Axle......................................................5-44
Noise Control System.....................................5-45
Tampering with Noise Control System
Prohibited.................................................5-45
Bulb Replacement..........................................5-46
Halogen Bulbs..............................................5-46
Headlamps..................................................5-47
Front Turn Signal, Sidemarker and
Parking Lamps..........................................5-48
Center High-Mounted Stoplamp (CHMSL).........5-49
Taillamps.....................................................5-49
Replacement Bulbs.......................................5-50
Windshield Wiper Blade Replacement..............5-51
Section 5 Service and Appearance Care
5-1

Checking the Fluid Level
Prepare your vehicle as follows:
1. Park your vehicle on a level place. Keep the engine
running.
2. With the parking brake applied, place the shift lever
in PARK (P).
3. With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, position
the shift lever in PARK (P).
4. Let the engine run at idle for three minutes or more.
Then, without shutting off the engine, follow these steps:
The transmission dipstick
is located near the center
of the engine compartment
and will be labeled with
the graphic shown.
SeeEngine Compartment Overview on page 5-12for
more information on location.
1. Flip the handle up and then pull out the dipstick
and wipe it with a clean rag or paper towel.2. Push it back in all the way, wait three seconds and
then pull it back out again.
3. Check both sides of the dipstick, and read the lower
level. The fluid level must be in the COLD area for
a cold check or in the HOT or cross-hatched
area for a hot check. Be sure to keep the dipstick
pointed down to get an accurate reading.
4. If the fluid level is in the acceptable range, push the
dipstick back in all the way; then flip the handle
down to lock the dipstick in place.
5-20

Jump Starting
If your vehicle’s battery has run down, you may want to
use another vehicle and some jumper cables to start your
vehicle. Be sure to use the following steps to do it safely.
{CAUTION:
Batteries can hurt you. They can be dangerous
because:
They contain acid that can burn you.
They contain gas that can explode
or ignite.
They contain enough electricity to
burn you.
If you do not follow these steps exactly, some or
all of these things can hurt you.
Notice:Ignoring these steps could result in costly
damage to your vehicle that would not be covered
by your warranty.
Trying to start your vehicle by pushing or pulling it
will not work, and it could damage your vehicle.
1. Check the other vehicle. It must have a 12-volt
battery with a negative ground system.Notice:If the other vehicle’s system is not a 12-volt
system with a negative ground, both vehicles can
be damaged. Only use vehicles with 12-volt systems
with negative grounds to jump start your vehicle.
2. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles are not touching
each other. If they are, it could cause a ground
connection you do not want. You would not be able
to start your vehicle, and the bad grounding
could damage the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake firmly on both vehicles involved in
the jump start procedure. Put an automatic
transmission in PARK (P) or a manual transmission
in NEUTRAL before setting the parking brake.
Notice:If you leave your radio or other accessories
on during the jump starting procedure, they could
be damaged. The repairs would not be covered
by your warranty. Always turn off your radio and
other accessories when jump starting your vehicle.
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or the accessory power outlet. Turn off
the radio and all lamps that are not needed. This
will avoid sparks and help save both batteries. And
it could save the radio!
5-39

Changing a Flat Tire
If a tire goes flat, avoid further tire and wheel damage
by driving slowly to a level place. Turn on your vehicle’s
hazard warning flashers. SeeHazard Warning Flashers
on page 3-5for more information.
{CAUTION:
Changing a tire can be dangerous. The vehicle
can slip off the jack and roll over or fall on you
or other people. You and they could be badly
injured or even killed. Find a level place to
change your tire. To help prevent the vehicle
from moving:
1. Set the parking brake rmly.
2. Put the shift lever in PARK (P).
3. Turn off the engine and do not restart
while the vehicle is raised.
4. Do not allow passengers to remain in
the vehicle.
CAUTION: (Continued)
CAUTION: (Continued)
To be even more certain the vehicle will not
move, you should put blocks at the front and
rear of the tire farthest away from the one
being changed. That would be the tire, on the
other side, at the opposite end of the vehicle.
When your vehicle has a flat tire, use the following
example as a guide to assist you in the placement of
wheel blocks.
5-70

Maintenance Footnotes
(Gasoline Engine)
This maintenance section applies to vehicles with a
gasoline engine. If your vehicle has a diesel engine, see
the maintenance schedule section in the DURAMAX
®
Diesel Engine Supplement.
†The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to
the completion of the vehicle’s useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the
maintenance be recorded.
#Lubricate the front suspension, kingpin bushings,
steering linkage, and rear driveline center splines.
(a)Visually inspect brake lines and hoses for proper
hook-up, binding, leaks, cracks, cha ng, etc. Inspect
disc brake pads for wear and rotors for surface
condition. Inspect other brake parts, including calipers,
parking brake, etc.
(b)Visually inspect front and rear suspension and
steering system for damaged, loose, or missing parts,
signs of wear, or lack of lubrication. Inspect power
steering lines and hoses for proper hook-up, binding,
leaks, cracks, cha ng, etc.(c)Visually inspect hoses and have them replaced if they
are cracked, swollen, or deteriorated. Inspect all pipes,
ttings, and clamps; replace with genuine GM parts as
needed. To help ensure proper operation, a pressure test
of the cooling system and pressure cap and cleaning the
outside of the radiator and air conditioning condenser is
recommended at least once a year.
(d)Visually inspect wiper blades for wear or cracking.
Replace wiper blades that appear worn or damaged
or that streak or miss areas of the windshield.
(e)Make sure the safety belt reminder light 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. Also look for any opened or broken airbag
coverings, and have them repaired or replaced.
The airbag system does not need regular maintenance.
(f)Lubricate all key lock cylinders, hood hinges, hood
prop rod pivot, hood latch assembly, secondary
latch, pivots, spring anchor, release pawl, rear
compartment hinges, latches, locks, fuel door hinge,
and any moving seat hardware. More frequent
lubrication may be required when exposed to a corrosive
environment. Applying silicone grease on weatherstrips
with a clean cloth will make them last longer, seal
better, and not stick or squeak.
6-8