2010 GMC YUKON DENALI maintenance schedule

Driving in Water
{WARNING:
Driving through rushing water can be dangerous.
Deep water can sweep your vehicle downstream
and you and your passengers could drown. If it is
only shallow water, it can still wash away the
ground from under your tires, and you could lose
traction and roll the vehicle over. Do not drive
through rushing water.
Heavy rain can mean flash flooding, and flood waters
demand extreme caution.
Find out how deep the water is before driving through it.
Do not try it if it is deep enough to cover the wheel
hubs, axles, or exhaust pipe —you probably will not get
through. Deep water can damage the axle and other
vehicle parts.
If the water is not too deep, drive slowly through it. At
faster speeds, water splashes on the ignition system
and the vehicle can stall. Stalling can also occur if you
get the tailpipe under water. If the tailpipe is under
water, you will never be able to start the engine. When
going through water, remember that when the brakes
get wet, it might take longer to stop. See Driving in Rain
and on Wet Roads on page 5‑24.
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 and check the fuel lines and cooling system
for any leakage.
The vehicle requires more frequent service due to
off-road use. Refer to the Maintenance Schedule for
additional information.
5-23

Parking on Hills
{WARNING:
Parking the vehicle on a hill with the trailer
attached can be dangerous. If something goes
wrong, the rig could start to move. People can be
injured, and both the vehicle and the trailer can be
damaged. When possible, always park the rig on
a flat surface.
If parking the rig on a hill: 1. Press the brake pedal, but do not shift into P (Park) yet. Turn the 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 brake pedal. Then apply the parking brake and shift into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
2. Start the engine
3. Shift into a gear
4. Release the parking brake
5. Let up on the brake pedal.
6. Drive slowly until the trailer is clear of the chocks.
7. Stop and have someone pick up and store the chocks.
Maintenance When Trailer Towing
The vehicle needs service more often when pulling a
trailer. See this manual's Maintenance Schedule or
Index for more information. Things that are especially
important in trailer operation are automatic transmission
fluid, engine oil, axle lubricant, belts, cooling system
and brake system. It is a good idea to inspect these
before and during the trip.
Check periodically to see that all hitch nuts and bolts
are tight.
5-58

Engine Air Cleaner/Filter
SeeEngine Compartment Overviewon page 6‑14for
the location of the engine air cleaner/filter.
Inspect the air cleaner/filter at the Maintenance II
intervals and replace it at the first oil change after each
50,000 mile (80 000 km) interval. See Scheduled
Maintenance
on page 7‑3for more information.
If driving on dusty/dirty conditions, inspect the filter at
each engine oil change.
How to Inspect the Engine
Air Cleaner/Filter
To inspect the air cleaner/filter, remove the engine
air cleaner/filter from the vehicle by following
Steps 1 through 6. When the engine air cleaner/filter is
removed, lightly shake it to release loose dust and dirt.
If the engine air cleaner/filter remains caked with dirt,
a new filter is required.
Replacing the Engine Air Cleaner/Filter
1. Locate the air
cleaner/filter
assembly.
See Engine
Compartment
Overview
on
page 6‑14.
2. Loosen the four screws on the cover of the housing and lift up the cover.
6-20

Automatic Transmission Fluid
When to Check and Change Automatic
Transmission Fluid
It is usually not necessary to check the transmission
fluid level. The only reason for fluid loss is a
transmission leak or overheating the transmission.
If you suspect a small leak, then use the following
checking procedures to check the fluid level. However,
if there is a large leak, then it may be necessary to have
the vehicle towed to a dealer/retailer service department
and have it repaired before driving the vehicle further.
Notice:Use of the incorrect automatic transmission
fluid may damage the vehicle, and the damages may
not be covered by the vehicle's warranty. Always
use the automatic transmission fluid listed in
Recommended Fluids and Lubricants on page 7‑11.
Change the fluid and filter at the intervals listed in the
Maintenance Schedule. See Scheduled Maintenance
on page 7‑3. Be sure to use the transmission fluid
listed in Recommended Fluids and Lubricantson
page 7‑11.
How to Check Automatic Transmission
Fluid
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.
Before checking the fluid level, prepare the vehicle as
follows:
1. Start the engine and park the vehicle on a level surface. Keep the engine running.
2. Apply the parking brake and place the shift lever in P (Park).
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, move the shift
lever back to P (Park).
6-22

Brakes
Brake Fluid
The brake master cylinder
reservoir is filled with
DOT 3 brake fluid. See
Engine Compartment
Overview
on page 6‑14for the location of the
reservoir.
There are only two reasons why the brake fluid level in
the reservoir might go down:
.The brake fluid level goes down because of normal
brake lining wear. When new linings are installed,
the fluid level goes back up.
.A fluid leak in the brake hydraulic system can also
cause a low fluid level. Have the brake hydraulic
system fixed, since a leak means that sooner or
later the brakes will not work well. Do not top off the brake fluid. Adding fluid does not
correct a leak. If fluid is added when the linings are
worn, there will be too much fluid when new brake
linings are installed. Add or remove brake fluid, as
necessary, only when work is done on the brake
hydraulic system.
{WARNING:
If too much brake fluid is added, it can spill on
the engine and burn, if the engine is hot enough.
You or others could be burned, and the vehicle
could be damaged. Add brake fluid only when
work is done on the brake hydraulic system.
See
“Checking Brake Fluid” in this section.
When the brake fluid falls to a low level, the brake
warning light comes on. See Brake System Warning
Light on page 4‑32.
Refer to the Maintenance Schedule to determine when
to check the brake fluid. See Scheduled Maintenance
on page 7‑3.
6-38

All-Wheel Drive
Transfer Case
If your vehicle is equipped with All-Wheel Drive, be sure
to perform the lubricant checks described in this
section. There are two additional systems that need
lubrication.
When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. SeeScheduled
Maintenance on page 7‑3.
How to Check Lubricant
(A) Drain Plug (B) Filler Plug
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,
located on the transfer case, you'll need to add some
lubricant. Add enough lubricant to raise the level to
the bottom of the filler plug hole. Use care not to
overtighten the plug.
6-47

What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. SeeRecommended Fluids and
Lubricants on page 7‑11.
Rear Axle
When to Check Lubricant
It is not necessary to regularly check rear axle fluid
unless you suspect there is a leak or you hear an
unusual noise. A fluid loss could indicate a problem.
Have it inspected and repaired.
All axle assemblies are filled by volume of fluid during
production. They are not filled to reach a certain level.
When checking the fluid level on any axle, variations in
the readings can be caused by factory fill differences
between the minimum and the maximum fluid volume.
Also, if a vehicle has just been driven before checking
the fluid level, it may appear lower than normal because
fluid has traveled out along the axle tubes and has not
drained back to the sump area. Therefore, a reading
taken five minutes after the vehicle has been driven will
appear to have a lower fluid level than a vehicle that
has been stationary for an hour or two. Remember that
the rear axle assembly must be supported to get a true
reading.
How to Check Lubricant
To get an accurate reading, the vehicle should be on a
level surface.
.For Two-Wheel-Drive vehicles, the proper level is
from 0.6 inch to 1.6 inches (15 mm to 40 mm) below
the bottom of the filler plug hole, located on the
rear axle. Add only enough fluid to reach the
proper level.
.For All-Wheel-Drive vehicles, the proper level is
from 0.04 inch to 0.75 inch (1.0 mm to 19.0 mm)
below the bottom of the filler plug hole, located on
the rear axle. Add only enough fluid to reach the
proper level.
6-48

What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. SeeRecommended Fluids and
Lubricants on page 7‑11.
Front Axle
When to Check and Change Lubricant
It is not necessary to regularly check front axle fluid
unless you suspect there is a leak or you hear an
unusual noise. A fluid loss could indicate a problem.
Have it inspected and repaired.
How to Check Lubricant
To get an accurate reading, the vehicle should be on a
level surface.A : Fill Plug
B : Drain Plug
.When the differential is cold, add enough lubricant
to raise the level from 0 (0 mm) to 1/8 inch
(3.2 mm) below the filler plug hole.
.When the differential is at operating temperature
(warm), add enough lubricant to raise the level to
the bottom of the filler plug hole.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. See Recommended Fluids and
Lubricants on page 7‑11.
6-49