2008 GMC YUKON DENALI Owners Manual

Replacing Brake System Parts
The braking system on a vehicle is complex. Its many
parts have to be of top quality and work well together if
the vehicle is to have really good braking. Your vehicle
was designed and tested with top-quality brake parts.
When you replace parts of the braking system — for
example, when the brake linings wear down and you
need new ones put in — be sure you get new approved
replacement parts. If you do not, the brakes might not
work properly. For example, if someone puts in brake
linings that are wrong for your vehicle, the balance
between the front and rear brakes can change — for the
worse. The braking performance you have come to
expect can change in many other ways if someone puts
in the wrong replacement brake parts.
Battery
Your vehicle has a maintenance free battery. When it is
time for a new battery, see your dealer/retailer for one
that has the replacement number shown on the original
battery’s label. SeeEngine Compartment Overview on
page 5-12for battery location.
Warning:Battery posts, terminals, and related
accessories contain lead and lead compounds,
chemicals known to the State of California to cause
cancer and reproductive harm. Wash hands after
handling.
Vehicle Storage
{CAUTION:
Batteries have acid that can burn you and gas
that can explode. You can be badly hurt if you
are not careful. SeeJump Starting on
page 5-40for tips on working around a battery
without getting hurt.
Infrequent Usage: If you drive your vehicle infrequently,
remove the black, negative (−) cable from the battery.
This will help keep the battery from running down.
Extended Storage: For extended storage of your vehicle,
remove the black, negative (−) cable from the battery or
use a battery trickle charger. This will help maintain the
charge of the battery over an extended period of time.
5-39

Jump Starting
If your vehicle’s battery (or batteries) 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 rmly on both vehicles involved
in the jump start procedure. Put the automatic
transmission in PARK (P) or a manual transmission
in NEUTRAL before setting the parking brake. If
you have a four-wheel-drive vehicle, be sure the
transfer case is in a drive gear, not in NEUTRAL.
5-40

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 outlets. Turn off the
radio and all the lamps that are not needed. This
avoids sparks and helps save both batteries. And it
could save the radio!
4. Open the hood on the other vehicle and locate the
positive (+) and negative (−) terminal locations on
that vehicle.
Your vehicle has a remote positive (+) jump starting
terminal and a remote negative (−) jump starting
terminal. You should always use these remote
terminals instead of the terminals on the battery.
If the vehicle has a remote positive (+) terminal, it is
located under a red plastic cover at the positive
battery post. To uncover the remote positive (+)
terminal, open the red plastic cover.The remote negative (−) terminal is a stud located
on the right front of the engine, where the
negative battery cable attaches.
SeeEngine Compartment Overview on page 5-12
for more information on the location of the remote
positive (+) and remote negative (−) terminals.
5-41

{CAUTION:
An electric fan can start up even when the
engine is not running and can injure you. Keep
hands, clothing and tools away from any
underhood electric fan.
{CAUTION:
Using a match near a battery can cause battery
gas to explode. People have been hurt doing
this, and some have been blinded. Use a
ashlight if you need more light.
CAUTION: (Continued)
CAUTION: (Continued)
Be sure the battery has enough water. You do
not need to add water to the battery installed
in your new vehicle. But if a battery has ller
caps, be sure the right amount of uid is there.
If it is low, add water to take care of that rst.
If you do not, explosive gas could be present.
Battery uid contains acid that can burn you.
Do not get it on you. If you accidentally get it
in your eyes or on your skin, ush the place
with water and get medical help immediately.
{CAUTION:
Fans or other moving engine parts can injure
you badly. Keep your hands away from moving
parts once the engine is running.
5-42

5. Check that the jumper cables do not have loose
or missing insulation. If they do, you could get a
shock. The vehicles could be damaged too.
Before you connect the cables, here are some
basic things you should know. Positive (+) will go to
positive (+) or to a remote positive (+) terminal if the
vehicle has one. Negative (−) will go to a heavy,
unpainted metal engine part or to a remote
negative (−) terminal if the vehicle has one.
Do not connect positive (+) to negative (−)oryou
will get a short that would damage the battery and
maybe other parts too. And do not connect the
negative (−) cable to the negative (−) terminal on the
dead battery because this can cause sparks.
6. Connect the red
positive (+) cable to the
positive (+) terminal
of the vehicle with the
dead battery. Use a
remote positive (+)
terminal if the vehicle
has one.7. Do not let the other end touch metal. Connect it to
the positive (+) terminal of the good battery. Use a
remote positive (+) terminal if the vehicle has one.
8. Now connect the black negative (−) cable to the
negative (−) terminal of the good battery. Use a
remote negative (−) terminal if the vehicle has one.
Do not let the other end touch anything until the
next step. The other end of the negative (−) cable
does not go to the dead battery. It goes to a heavy,
unpainted metal engine part or to the remote
negative (−) terminal on the vehicle with the dead
battery.
9. Connect the other end of the negative (−) cable to
the remote negative (−) terminal, on the vehicle with
the dead battery.
10. Now start the vehicle with the good battery and run
the engine for a while.
11. Try to start the vehicle that had the dead battery.
If it will not start after a few tries, it probably needs
service.
5-43

Notice:If the jumper cables are connected or
removed in the wrong order, electrical shorting may
occur and damage the vehicle. The repairs would
not be covered by your warranty. Always connect
and remove the jumper cables in the correct order,
making sure that the cables do not touch each other
or other metal.
A. Heavy, Unpainted Metal Engine Part or Remote
Negative (−) Terminal
B. Good Battery or Remote Positive (+) and Remote
Negative (−) Terminals
C. Dead Battery or Remote Positive (+) TerminalTo disconnect the jumper cables from both vehicles do
the following:
1. Disconnect the black negative (−) cable from the
vehicle that had the bad battery.
2. Disconnect the black negative (−) cable from the
vehicle with the good battery.
3. Disconnect the red positive (+) cable from the
vehicle with the good battery.
4. Disconnect the red positive (+) cable from the other
vehicle.
5. Return the remote positive (+) terminal cover, if the
vehicle has one, to its original position.
Jumper Cable Removal
5-44

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 6-4.
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 ller 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 ller plug hole. Use care not to overtighten
the plug.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. SeeRecommended Fluids
and Lubricants on page 6-12. (A) Drain Plug (B) Filler Plug
5-45

Rear Axle
When to Check Lubricant
It is not necessary to regularly check rear axle uid
unless you suspect there is a leak or you hear an
unusual noise. A uid loss could indicate a problem.
Have it inspected and repaired.
All axle assemblies are lled by volume of uid during
production. They are not lled to reach a certain level.
When checking the uid level on any axle, variations in
the readings can be caused by factory ll differences
between the minimum and the maximum uid volume.
Also, if a vehicle has just been driven before checking the
uid level, it may appear lower than normal because uid
has traveled out along the axle tubes and has not drained
back to the sump area. Therefore, a reading taken
ve minutes after the vehicle has been driven will appear
to have a lower uid 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 ller plug hole, located on
the rear axle. Add only enough uid 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 ller plug hole, located on the rear
axle. Add only enough uid to reach the proper level.
5-46