2008 GMC YUKON towing

Seats and Restraint Systems........................... 1-1
Front Seats
............................................... 1-2
Rear Seats
..............................................1-11
Safety Belts
.............................................1-30
Child Restraints
.......................................1-51
Airbag System
.........................................1-76
Restraint System Check
............................1-92
Features and Controls..................................... 2-1
Keys
........................................................ 2-3
Doors and Locks
......................................2-10
Windows
.................................................2-19
Theft-Deterrent Systems
............................2-22
Starting and Operating Your Vehicle
...........2-26
Mirrors
....................................................2-49
Object Detection Systems
..........................2-58
OnStar
®System
......................................2-60
Universal Home Remote System
................2-64
Storage Areas
.........................................2-71
Sunroof
..................................................2-74
Instrument Panel............................................. 3-1
Instrument Panel Overview
.......................... 3-4
Climate Controls
......................................3-23
Warning Lights, Gages, and Indicators
........3-37
Driver Information Center (DIC)
..................3-55
Audio System(s)
.......................................3-81Driving Your Vehicle....................................... 4-1
Your Driving, the Road, and Your Vehicle
..... 4-2
Towing
...................................................4-45
Service and Appearance Care.......................... 5-1
Service
..................................................... 5-3
Fuel
......................................................... 5-5
Checking Things Under the Hood
...............5-12
Rear Axle
...............................................5-52
Four-Wheel Drive
.....................................5-54
Front Axle
...............................................5-55
Headlamp Aiming
.....................................5-56
Bulb Replacement
....................................5-59
Windshield Wiper Blade Replacement
.........5-62
Tires
......................................................5-64
Appearance Care
...................................5-108
Vehicle Identication
...............................5-116
Electrical System
....................................5-117
Capacities and Specications
...................5-124
Maintenance Schedule..................................... 6-1
Maintenance Schedule
................................ 6-2
Customer Assistance Information.................... 7-1
Customer Assistance and Information
........... 7-2
Reporting Safety Defects
...........................7-14
Vehicle Data Recording and Privacy
...........7-16
Index................................................................ 1
2008 GMC Yukon, Yukon XL Owner ManualM

If you ever pull the shoulder portion of the belt out all
the way, you will engage the child restraint locking
feature. This may unintentionally cause the passenger
sensing system to turn the airbag(s) off for some
adult size occupants. If this happens, just let the belt go
back all the way and start again.
{CAUTION:
If the airbag readiness light in the instrument
panel cluster ever comes on and stays on, it
means that something may be wrong with the
airbag system. If this ever happens, have the
vehicle serviced promptly, because an
adult-size person sitting in the right front
passenger’s seat may not have the protection
of the airbag(s). SeeAirbag Readiness Light
on page 3-40for more on this, including
important safety information.A thick layer of additional material, such as a blanket or
cushion, or aftermarket equipment such as seat
covers, seat heaters, and seat massagers can affect
how well the passenger sensing system operates.
We recommend that you not use seat covers or other
aftermarket equipment other than any that GM has
approved for your specic vehicle. SeeAdding
Equipment to Your Airbag-Equipped Vehicle on
page 1-90for more information about modications that
can affect how the system operates.
{CAUTION:
Stowing of articles under the passenger’s seat
or between the passenger’s seat cushion and
seatback may interfere with the proper
operation of the passenger sensing system.
1-89

Starting and Operating Your
Vehicle
New Vehicle Break-In
Notice:Your vehicle does not need an elaborate
break-in. But it will perform better in the long run if
you follow these guidelines:
Keep your speed at 55 mph (88 km/h) or less for
the rst 500 miles (805 km).
Do not drive at any one constant speed, fast or
slow, for the rst 500 miles (805 km). Do not
make full-throttle starts. Avoid downshifting to
brake or slow the vehicle.
Avoid making hard stops for the rst 200 miles
(322 km) or so. During this time the new brake
linings are not yet broken in. Hard stops
with new linings can mean premature wear and
earlier replacement. Follow this breaking-in
guideline every time you get new brake linings.
Do not tow a trailer during break-in. SeeTowing
a Trailer on page 4-49for the trailer towing
capabilities of your vehicle and more
information.
Following break-in, engine speed and load can be
gradually increased.
Ignition Positions
Use the key to turn the
ignition switch to four
different positions.
In order to shift out of PARK (P), ignition must be in the
ON/RUN or ACC/ACCESSORY and the regular brake
pedal must be applied.
A (LOCK/OFF):This position locks the ignition and
transmission. It is a theft-deterrent feature. The key can
only be removed when the ignition is turned to
LOCK/OFF.
Notice:Using a tool to force the key from the
ignition switch could cause damage or break the
key. Use the correct key and turn the key only with
your hand. Make sure the key is all the way in.
2-26

See “Range Selection Mode” later in this section.
PARK (P):This position locks your rear wheels. It is
the best position to use when you start the engine
because your vehicle cannot move easily. When parked
on a hill, especially when the vehicle has a heavy
load, you might notice an increase in the effort to shift
out of Park. See Torque Lock (Automatic Transmission)
underShifting Into PARK (P) on page 2-44for more
information.
{CAUTION:
It is dangerous to get out of your vehicle if the
shift lever is not fully in PARK (P) with the
parking brake rmly set. Your vehicle can roll.
Do not leave your vehicle when the engine is
running unless you have to. If you have left the
engine running, the vehicle can move
suddenly. You or others could be injured. To
be sure your vehicle will not move, even when
you are on fairly level ground, always set your
parking brake and move the shift lever to
PARK (P). SeeShifting Into PARK (P) on
page 2-44. If you are pulling a trailer, see
Towing a Trailer on page 4-49. Allison Transmission
®or Hydra-Matic®6-Speed
Automatic Transmission
2-32

DRIVE (D):This position is for normal driving. It
provides the best fuel economy for your vehicle. If you
need more power for passing, and you are:
Going less than about 35 mph (55 km/h), push your
accelerator pedal about halfway down.
Going about 35 mph (55 km/h) or more, push the
accelerator all the way down.
By doing this, the vehicle shifts down to the next
gear and has more power.
DRIVE (D) can be used when towing a trailer, carrying a
heavy load, driving on steep hills, or for off-road
driving. You might want to shift the transmission to a
lower gear selection if the transmission shifts too often.
Downshifting the transmission in slippery road
conditions could result in skidding. See Skidding under
Loss of Control on page 4-12.
Your vehicle has a shift stabilization feature that adjusts
the transmission shifting to the current driving
conditions in order to reduce rapid upshifts and
downshifts. This shift stabilization feature is designed to
determine, before making an upshift, if the engine is
able to maintain vehicle speed by analyzing things such
as vehicle speed, throttle position, and vehicle load.If the shift stabilization feature determines that a current
vehicle speed cannot be maintained, the transmission
does not upshift and instead holds the current gear.
In some cases, this could appear to be a delayed shift,
however the transmission is operating normally.
Your vehicle’s transmission uses adaptive shift controls.
Adaptive shift controls continually compares key shift
parameters to pre-programmed ideal shifts stored in the
transmissions computer. The transmission constantly
makes adjustments to improve vehicle performance
according to how the vehicle is being used, such as with
a heavy load or when temperature changes. During
this adaptive shift control process, shifting might
feel different as the transmission determines the best
settings.
When temperatures are very cold, the Allison
Transmission
®and Hydra-Matic®6-Speed
transmission’s gear shifting could be delayed providing
more stable shifts until the engine warms up. Shifts
could be more noticeable with a cold transmission. This
difference in shifting is normal.
2-34

MANUAL MODE (M):This position, is available on
vehicles with the Allison Transmission®or Hydra-Matic®
6-Speed transmission. It lets drivers select the range
of gears appropriate for current driving conditions. If your
vehicle has this feature, see Range Select Mode
(Allison Transmission
®or Hydra-Matic®6-Speed
transmission) later in this section.
THIRD (3):This position is also used for normal driving.
It reduces vehicle speed more than DRIVE (D) without
using the brakes. You might choose THIRD (3)
instead of DRIVE (D) when driving on hilly, winding
roads, when towing a trailer, so there is less shifting
between gears and when going down a steep hill.
SECOND (2):This position reduces vehicle speed even
more than THIRD (3) without using your brakes. You can
use SECOND (2) on hills. It can help control your speed
as you go down steep mountain roads, but then you
would also want to use the brakes off and on.
If you manually select SECOND (2) in an automatic
transmission, the transmission will start in second gear.
You can use this feature for reducing the speed of the
rear wheels when you are trying to start your vehicle from
a stop on slippery road surfaces.FIRST (1):For the Hydra-Matic
®4-Speed transmission
this position reduces vehicle speed even more than
SECOND (2) without using the brakes. You can use it
on very steep hills, or in deep snow or mud. If the
shift lever is put in FIRST (1) while the vehicle is moving
forward, the transmission does not shift into rst gear
until the vehicle is going slowly enough.
For an Allison Transmission
®or Hydra-Matic®6-Speed
transmission, this position reduces vehicle speed
without using your brakes. You can use it for
major/severe downgrades and off-road driving where
the vehicle would otherwise accelerate due to steepness
of grade. When you shift to FIRST (1) it provides the
lowest gear appropriate to your current road speed and
continues to downshift as the vehicle slows, eventually
downshifting to FIRST (1) gear.
Notice:Spinning the tires or holding the vehicle in
one place on a hill using only the accelerator
pedal may damage the transmission. The repair will
not be covered by your warranty. If you are stuck,
do not spin the tires. When stopping on a hill,
use the brakes to hold the vehicle in place.
2-35

Range Selection Mode (Allison®or
Hydra-Matic®6-Speed Transmission)
Your vehicle may have a Range Selection Mode.
The Range Selection Mode helps control the vehicle’s
transmission and vehicle speed while driving down hill
or towing a trailer by letting you select a desired range
of gears.
To use this feature, do the following:
1. Move the shift lever to the MANUAL MODE (M).
2. Press the plus/minus buttons, located on the
steering column shift lever, to select the desired
range of gears for your current driving conditions.When MANUAL MODE (M) is selected a number
displays next to the M, indicating the current gear.
This number is the highest gear that can be used.
However, your vehicle can automatically shift to lower
gears as it adjusts to driving conditions. This means that
all gears below that number are available. When
FIFTH (5) is selected, FIRST (1) through FIFTH (5)
gears are automatically shifted by the vehicle, but
SIXTH (6) cannot be used until the plus/minus button
located on the steering column lever is used to change
to the gear.
Grade Braking is not available when the Range
Selection Mode is active. SeeTow/Haul Mode on
page 2-37.
While using the Range Selection mode feature, cruise
control and the Tow/Haul mode can be used.
Notice:Spinning the tires or holding the vehicle in
one place on a hill using only the accelerator
pedal may damage the transmission. The repair will
not be covered by your warranty. If you are stuck,
do not spin the tires. When stopping on a hill,
use the brakes to hold the vehicle in place.
2-36

Low Traction Mode
If your vehicle has the Allison Transmission®,orthe
Hydra-Matic®6-Speed Automatic Transmission, it has a
Low Traction Mode that assist in vehicle acceleration
when road conditions are slippery, such as with ice
or snow. While the vehicle is at a stop, select the second
gear range using the Range Selection system. This
will limit torque to the wheels after it detects wheel slip,
preventing the tires from spinning.
Tow/Haul Mode
Your vehicle has a Tow/Haul mode. The selector button
is located on the end of the column shift lever.You can use this feature to assist when towing or
hauling a heavy load or if there is a need to charge a
battery installed in a trailer. SeeTowing a Trailer
on page 4-49for more information.
When Tow/Haul mode is
selected the Tow/Haul
indicator light will come on.
The Tow/Haul mode works with the Autoride
®feature, if
the vehicle has this, to enhance the ride when
trailering or with a loaded vehicle. SeeAutoride
®on
page 4-49.
2-37