2002 GMC YUKON XL DENALI maintenance

4-15 Before You Go Off-Roading
There are some things to do before you go out. For
example, be sure to have all necessary maintenance and
service work done. Check to make sure all underbody
shields (if so equipped) are properly attached. Is there
enough fuel? Is the spare tire fully inflated? Are the
fluid levels up where they should be? What are the local
laws that apply to off
-roading where you'll be driving?
If you don't know, you should check with law
enforcement people in the area. Will you be on
someone's private land? If so, be sure to get the
necessary permission.
Loading Your Vehicle for Off-Road Driving
There are some important things to remember about
how to load your vehicle.

The heaviest things should be on the load floor and
forward of your rear axle. Put heavier items as far
forward as you can.

Be sure the load is secured properly, so driving on
the off
-road terrain doesn't toss things around.
CAUTION:

Cargo on the load floor piled higher than
the seatbacks can be thrown forward
during a sudden stop. You or your
passengers could be injured. Keep cargo
below the top of the seatbacks.

Unsecured cargo on the load floor can
be tossed about when driving over rough
terrain. You or your passengers can be
struck by flying objects. Secure the
cargo properly.

Heavy loads on the roof raise the vehicle's
center of gravity, making it more likely to
roll over. You can be seriously or fatally
injured if the vehicle rolls over. Put heavy
loads inside the cargo area, not on the roof.
Keep cargo in the cargo area as far forward
and low as possible.
You'll find other important information in this manual.
See ªVehicle Loading,º ªLuggage Carrierº and ªTiresº
in the Index.

4-27
If the water isn't too deep, then drive through it slowly. At
fast speeds, water splashes on your ignition system and
your vehicle can stall. Stalling can also occur if you get
your tailpipe under water. And, as long as your tailpipe is
under water, you'll never be able to start your engine.
When you go through water, remember that when your
brakes get wet, it may take you longer to stop.
CAUTION:
Driving through rushing water can be dangerous.
Deep water can sweep your vehicle downstream
and you and your passengers could drown. If it's
only shallow water, it can still wash away the
ground from under your tires, and you could lose
traction and roll the vehicle over. Don't drive
through rushing water.
See ªDriving Through Waterº in the Index for more
information on driving through water.
After Off-Road Driving
Remove any brush or debris that has collected on the
underbody, chassis or under the hood. These
accumulations can be a fire hazard.
After operation in mud or sand, have the brake linings
cleaned and checked. These substances can cause
glazing and uneven braking. Check the body structure,
steering, suspension, wheels, tires and exhaust system
for damage. Also, check the fuel lines and cooling
system for any leakage.
Your vehicle will require more frequent service due to
off
-road use. Refer to the Maintenance Schedule for
additional information.

4-54 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, 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
Heavy-Duty Trailer Wiring Package
Your vehicle is equipped with the seven-wire trailer
towing harness. This harness with a seven
-pin universal
heavy
-duty trailer connector is attached to a bracket on
the platform hitch.

6-
6-1
Section 6 Service and Appearance Care
Here you will find information about the care of your vehicle. This section begins with service and fuel information,
and then it shows how to check important fluid and lubricant levels. There is also technical information about your
vehicle, and a part devoted to its appearance care.
6
-2 Service
6
-3 Fuel
6
-5 Fuels in Foreign Countries
6
-6 Filling Your Tank
6
-8 Filling a Portable Fuel Container
6
-8 Checking Things Under the Hood
6
-11 Engine Oil
6
-17 Engine Air Cleaner/Filter
6
-19 Passenger Compartment Air Filter
6
-20 Automatic Transmission Fluid
6
-23 Rear Axle
6
-24 All-Wheel Drive
6
-26 Engine Coolant
6
-29 Coolant Surge Tank Pressure Cap
6
-30 Power Steering Fluid6
-31 Windshield Washer Fluid
6
-32 Brakes
6
-36 Battery
6
-37 Bulb Replacement
6
-41 Windshield Wiper Blade Replacement
6
-42 Tires
6
-51 Appearance Care
6
-51 Cleaning the Inside of Your Vehicle
6
-55 Cleaning the Outside of Your Vehicle
6
-59 GM Vehicle Care/Appearance Materials
6
-60 Vehicle Identification Number (VIN)
6
-61 Electrical System
6
-69 Replacement Bulbs
6
-70 Capacities and Specifications
6
-71 Normal Maintenance Replacement Parts

6-2
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 vehicle than this manual
can. To order the proper service manual, see ªService
and Owner Publicationsº in the Index.
Your vehicle has an air bag system. Before attempting to
do your own service work, see ªServicing Your Air
Bag
-Equipped Vehicleº in the Index.
You should keep a record with all parts receipts and list
the mileage and the date of any service work you
perform. See ªMaintenance Recordº in the Index.

6-3
CAUTION:
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. ªEnglishº and ªmetricº
fasteners can be easily confused. If you use
the wrong fasteners, parts can later break
or fall off. You could be hurt.
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.
Fuel
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 it is bad
enough, it can 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.
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. Gasolines
meeting these specifications could provide improved
driveability and emission control system performance
compared to other gasolines.

6-18
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 cleaner/filter.
5. Install the cover and tighten the screws.Refer to the Maintenance Schedule to determine when to
replace the engine air cleaner/filter. See ªOwner Checks
and Servicesº in the Index.
CAUTION:
Operating the engine with 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 cleaner/filter off.
NOTICE:
If the air cleaner/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 cleaner/filter in place when
you're driving.

6-19
Passenger Compartment Air Filter
The filter is located under the instrument panel below
the glove compartment.
To replace the passenger compartment air filter do
the following:
1. Remove the bolts on the access panel and set the
panel aside. Because this operation can be a little
difficult, you may choose to have it done at your
dealer's service department.
2. Reach under the
instrument panel
towards the front of
the vehicle and pull
downward on the
filter retaining bracket.3. Remove the air filter by pulling downward on the
element. Remove the second portion of the air filter
by sliding it towards the rear of the vehicle and then
pulling downward.
4. Install the new filter by reversing the steps listed
previously. Be sure to follow any instructions that
may be included in the replacement filter package.
Refer to the Maintenance Schedule to determine
when to replace the passenger compartment air filter.
See ªScheduled Maintenanceº in the Index.