2003 GMC YUKON DENALI maintenance

Trailer Recommendations
You must subtract your hitch loads from the Cargo
Weight Rating (CWR). CWR is the maximum weight of
the load your vehicle can carry.
It doesn’t include
the weight of the people inside. But you can figure about
150 Ibs. (68 kg) for each seat. The total cargo load
must
not be more than your vehicle’s CWR.
Weigh your vehicle with the trailer attached,
so that you
won’t
go over the GVWR or GAWR. If you are using
a weight-distributing hitch, weigh the vehicle without the
spring bars in place.
You’ll get the best performance if you spread out the
weight of your load the right way, and
if you choose the
correct hitch and trailer brakes.
For more information, see
Towing a Trailer on
page 4-47.
Towing a Trailer
Is
IOU don’_ Ase e correct equipment anc-
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.
Nofice: Pulling a trailer improperly can damage
your vehicle and result
in costly repairs not covered
by your warranty.
To pull a trailer correctly, follow
the advice
in this part, and see your dealer for
important information about towing a trailer with
your vehicle. Additional rear axle maintenance
is required for a vehicle used to tow a trailer. See
“Scheduled Maintenance Services” in the Index.
4-47

Parking on Hills
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
2. Have someone place chocks under the trailer
3. When the wheel chocks are in place, release the
PARK
(P) yet.
wheels.
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
5. Release the regular brakes.
parking brake
and shift into PARK
(P).
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.
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, belts, 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.
4-55

Section 5 Service and Appearance Care
Windshield Wiper Blade Replacement .............. 5.54
Tires .............................................................. 5.55
Inflation .. Tire Pressure ............................... 5-55
Tire Inspection and Rotation ........................... 5.56
When It
Is Time for New Tires ....................... 5-58
Buying New Tires
......................................... 5.58
Uniform Tire Quality Grading
.......................... 5.59
Wheel Alignment and Tire Balance
.................. 5-61
Wheel Replacement
...................................... 5.61
Tire Chains
.................................................. 5-62
If a Tire Goes Flat ........................................ 5.63
Spare Tire
................................................... 5.77
Appearance Care ............................................ 5.78
Cleaning the Inside of Your Vehicle
................. 5-78
Care of Safety Belts
...................................... 5.80
Weatherstrips
............................................... 5.80
Changing a Flat Tire
..................................... 5-63 Cleaning the Outside
of Your Vehicle
.............. 5-81
Sheet Metal Damage
.................................... 25-83
Finish Damage
............................................ 5-83
Underbody Maintenance
............................... 5-84
Chemical Paint Spotting
................................ 5-84
GM Vehicle Care/Appearance Materials
........... 5-84
Vehicle Identification .................................... ,.5-86
Service Parts Identification Label
..................... 5-86
Electrical System ............................................ 5-87
Add-on Electrical Equipment .......................... 5-87
Windshield Wiper Fuses
............................... 25-87
Power Windows
and Other Power Options ....... 5-87
Fuses and Circuit Breakers
............................ 5-87
Capacities and Specifications .......................... 5-96
Capacities and Specifications ......................... 5-96
Vehicle
Identification Number (VIN)
................ 5-86
Normal Maintenance Replacement Parts ...... 5-98
5-2

Service
Your dealer knows your vehicle best and wants you to
be happy with it. We hope you’ll go to your dealer
for all your service needs. You’ll get genuine
GM parts
and GM-trained and supported service people.
We hope you’ll want to keep your GM vehicle all GM.
Genuine GM parts have one of these marks:
Doing Your Own Service Work
If you want to do some of your own service work, you’ll
want to use the proper service manual. It tells you
much more about how to service your vehicie
than this
manual can. To order the proper service manual,
see Service Publications Ordering Information
on
page 7-10.
Your vehicle has an air bag system. Before attempting
to do your own service work, see Servicing Your Air
Bag-Equipped Vehicle on page
1-85.
You should keep a record with all parts receipts and list
the mileage and the date of any service work you
perform. See Part
E: Maintenance Record on page 6-17.
5-3

You can be injured and your vehicle could be
damaged if you try to do service work on a
vehicle without knowing enough about
it.
Be sure you have sufficient knowledge,
experience, the proper replacement parts and tools before you attempt any vehicle
maintenance task.
Be sure to use the proper nuts, bolts and
other fasteners. “English” and “metric”
fasteners can be easily confused.
If you
use the wrong fasteners, parts can later
break or fall
off. You could be hurt.
1
Adding Equipment to the Outside of
Your
Vehicle
Things you might add to the outside of your vehicle can
affect the airflow around it. This may cause wind
noise and affect windshield washer performance.
Check with your dealer before adding equipment
to the
outside of
your vehicle.
5-4

Fuel
Use of the recommended fuel is an important part of the
proper maintenance
of your vehicle.
Gasoline Octane
Use regular unleaded gasoline with a posted octane
of 87 or higher.
If the octane is less than 87, you may
get a heavy knocking noise when you drive. If this
occurs, use a gasoline rated at 87 octane or higher as
soon as possible. Otherwise, you might damage
your engine.
A little pinging noise when you accelerate
or drive uphill
is considered normal. This does not
indicate a problem exists or that a higher-octane fuel is
necessary. If you are using 87 octane or higher-octane
fuel and hear heavy knocking, your engine needs
service.
Gasoline Specifications
It is recommended that gasoline meet specifications
which were developed by the American Automobile
Manufacturers Association and endorsed
by the
Canadian Vehicle Manufacturers Association for better
vehicle performance and engine protection. Gasoline meeting these specifications could provide improved
driveability and emission control system performance
compared to other gasoline.
In Canada, look for the
"Auto Makers' Choice"
label on the pump.
Canada Only
5-5

I
1. To remove the engine air cleaner/filter, loosen the
screws on the cover.
2. Lift the cover upward and remove the engine air
cleaner/filter
out of the air cleaner housing. Care
should be taken to dislodge as little dirt as possible.
3. Clean the filter sealing surface and the housing.
4. Install the new engine air cleanedfilter. Refer
to the Maintenance Schedule to determine when
to replace the engine air cleanedfilter. See
Part 5:
Owner Checks and Services on page 6- 10.
Operating L.L engine _____. the air cleaner/filter
off can cause you or others to be burned. The
air cleaner not only cleans the air,
it stops
flame if the engine backfires.
If it isn’t there
and the engine backfires, you could be burned. Don’t drive with
it off, and be careful working
on the engine with the air cleanedfilter
off.
Notice: If the air cieaner/filter is off, a backfire can
cause a damaging engine fire. And, dirt can
easily get into your engine, which will damage
it.
Always have the air cleanedfilter in place when
you’re driving.
5. Install the cover and tighten the screws.
5-1 9

Automatic Transmission Fluid
When to Check and Change
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change both the fluid and filter every
50,000 miles
(83
000 km) if the vehicle’s GVWR is over 8,600 or if
the vehicle is mainly driven under one or more of these
conditions:
In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C) or higher.
0 In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or delivery
service.
If your vehicle’s GVWR is not over 8,600 and you do
not use your vehicle under any of these conditions,
change the fluid and filter every
100,000 miles
(1 66 000 km).
How to Check
Because this operation can be a little difficult, you may
choose to have this done at the dealership service
department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
Notice: Too much or too little fluid can damage
your transmission. Too much can mean that some of the fluid could come out and fall
on hot engine
part or exhaust system parts, starting a fire.
Too little fluid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission fluid.
Wait at least 30 minutes before checking the
transmission fluid level
if you have been driving:
When outside temperatures are above 90°F (32°C).
At high speed for quite a while.
In heavy traffic - especially in hot weather.
While pulling a trailer.
See
Part A: Scheduled Maintenance Services on
page 6-4.
5-20