2002 GMC YUKON XL DENALI service schedule

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.

6-18
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.

6-20
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 is mainly driven under one or
more of these conditions:

In heavy city traffic where the outside temperature
regularly reaches 90F (32C) or higher.

In hilly or mountainous terrain.

When doing frequent trailer towing.

Uses such as found in taxi, police or delivery service.
If you do not use your vehicle under any of
these conditions, change the fluid and filter
every 100,000 miles (166 000 km).
See ªScheduled Maintenance Servicesº in the Index.
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
parts 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.

6-23 How to Add Fluid
Refer to the Maintenance Schedule to determine what
kind of transmission fluid to use. See ªRecommended
Fluids and Lubricantsº in the Index.
Add fluid only after checking the transmission fluid
while it is hot. (A cold check is used only as a
reference.) If the fluid level is low, add only enough of
the proper fluid to bring the level up to the HOT area for
a hot check. It doesn't take much fluid, generally less
than one pint (0.5 L). Don't overfill.
NOTICE:
We recommend you use only fluid labeled
DEXRON-III, because fluid with that label is
made especially for your automatic transmission.
Damage caused by fluid other than DEXRON
-III
is not covered by your new vehicle warranty.

After adding fluid, recheck the fluid level as
described under ªHow to Check.º

When the correct fluid level is obtained, push the
dipstick back in all the way; then flip the handle
down to lock the dipstick in place.
Rear Axle
When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. See ªScheduled
Maintenance Servicesº in the Index.
How to Check Lubricant
To get an accurate reading, the vehicle should be on a
level surface.
The proper level is from 5/8 inch to 1 5/8 inch
(15 mm to 40 mm) below the bottom of the filler plug
hole. Add only enough fluid to reach the proper level.

6-25
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. See ªRecommended Fluids and
Lubricantsº in the Index.
Front Axle
When to Check and Change Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant and when to change it. See
ªScheduled Maintenance Servicesº in the Index.How to Check Lubricant
To get an accurate reading, the vehicle should be on a
level surface.
If the level is below the bottom of the filler plug hole,
you may need to add some lubricant.

6-44 Tire Inspection and Rotation
Tires should be rotated every 6,000 to 8,000 miles
(10 000 to 13 000 km). Any time you notice unusual
wear, rotate your tires as soon as possible and check
wheel alignment. Also check for damaged tires or
wheels. See ªWhen It's Time for New Tiresº and
ªWheel Replacementº later in this section for more
information. Make sure the spare tire is stored securely.
Push, pull, and then try to rotate or turn the tire. If it
moves, use the wheel wrench to tighten the cable. See
ªStoring a Flat or Spare Tire and Toolsº in the Index.
The purpose of regular rotation is to achieve more uniform
wear for all tires on the vehicle. The first rotation is the
most important. See ªScheduled Maintenance Servicesº in
the Index for scheduled rotation intervals.
When rotating your tires, always use the correct rotation
pattern shown here. Don't include the spare tire in your
tire rotation.
After the tires have been rotated, adjust the front and rear
inflation pressures as shown on the Certification/Tire label.
Make certain that all wheel nuts are properly tightened.
See ªWheel Nut Torqueº in the Index.
CAUTION:
Rust or dirt on a wheel, or on the parts to which
it is fastened, can make wheel nuts become loose
after a time. The wheel could come off and cause
an accident. When you change a wheel, remove
any rust or dirt from places where the wheel
attaches to the vehicle. In an emergency, you
can use a cloth or a paper towel to do this; but
be sure to use a scraper or wire brush later, if
you need to, to get all the rust or dirt off. See
ªChanging a Flat Tireº in the Index.