2008 GMC YUKON XL lock

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

Four-Wheel Drive
If your vehicle has four-wheel drive, you can send your
engine’s driving power to all four wheels for extra
traction. Read the part that follows before using
four-wheel drive.
Notice:Driving on clean, dry pavement in
Four-Wheel-Drive High or Four-Wheel-Drive Low for
an extended period of time may cause premature
wear on your vehicle’s powertrain. Do not drive on
clean, dry pavement in Four-Wheel-Drive High or
Four-Wheel-Drive Low for extended periods of time.
While driving on clean dry pavement and during tight
turns, you may experience a vibration in the steering
system.
Front Axle Locking Feature
The front axle locks and unlocks automatically when
you shift the transfer case. Some delay for the axle to
lock or unlock is normal.
Automatic Transfer Case
The transfer case knob is
located to the left of the
instrument panel cluster.
Your vehicle has Four Wheel Drive with StabiliTrak
®.
For information on StabiliTrak®, seeStabiliTrak®System
on page 4-6.
Use this dial to shift into and out of four-wheel drive.
You can choose among ve driving settings:
Indicator lights in the switches show you which setting
you are in. The indicator lights will come on briey when
you turn on the ignition and the last chosen setting will
stay on. If the lights do not come on, you should take your
vehicle in for service. An indicator light will ash while
shifting. Fast ashing means the conditions were not met
to make the desired shift, typically the vehicle was going
too fast, the automatic transmission was not in neutral.
2-38

Shifting Out of Four-Wheel Drive Low
To shift from Four-Wheel Drive Low to Four-Wheel Drive
High, AUTO, or Two-Wheel Drive High, your vehicle
must be stopped or moving less than 3 mph (5 km/h)
with the transmission in NEUTRAL (N) and the ignition in
ON/RUN. The preferred method for shifting out of
Four-Wheel Drive Low is to have your vehicle moving
1 to 2 mph (1.6 to 3.2 km/h). Turn the knob to the
Four-Wheel Drive High, AUTO, or Two-Wheel Drive
High position. You must wait for the Four-Wheel Drive
High, AUTO, or Two-Wheel Drive High indicator
light to stop ashing and remain on before shifting your
transmission into gear.
Notice:Shifting the transmission into gear before
the Four-Wheel Drive Low indicator light has
stopped ashing could damage the transfer case.
To help avoid damaging your vehicle, always
wait for the Four-Wheel Drive Low indicator light to
stop ashing before shifting the transmission
into gear.
The vehicle may have signicant engagement noise and
bump when shifting between Four-Wheel Drive Low
and Four-Wheel Drive High ranges or from NEUTRAL
while the engine is running.If the knob is turned to the Four-Wheel Drive High,
AUTO, or Two-Wheel Drive High switch position when
your vehicle is in gear and/or moving, the Four-Wheel
Drive High, AUTO or Two-Wheel Drive High indicator
light will ash for 30 seconds but will not complete
the shift unless your vehicle is moving less than 3 mph
(5 km/h) and the transmission is in NEUTRAL (N).
Shifting into NEUTRAL
To shift the transfer case to NEUTRAL do the following:
1. Make sure the vehicle is parked so that it will
not roll.
2. Set the parking brake and apply the regular brake
pedal. SeeParking Brake on page 2-43for more
information.
3. Start the vehicle or turn the ignition to ON/RUN.
4. Put the transmission in NEUTRAL (N).
5. Shift the transfer case to Two-Wheel Drive High.
6. Turn the transfer case dial clockwise to NEUTRAL
till it stops and hold it for 10 seconds. Then slowly
release the dial to the four low position. The
NEUTRAL light will come on when the transfer case
shift to NEUTRAL is complete.
2-41

7. If the engine is running, verify that the transfer case
is in NEUTRAL (N) by shifting the transmission to
REVERSE (R) for one second, then shift the
transmission to DRIVE (D) for one second.
8. Turn the ignition to ACC/ACCESSORY, which will
turn the engine off.
9. Place the transmission shift lever in PARK (P).
10. Release the parking brake prior to moving
the vehicle.
11. Turn the ignition to LOCK/OFF.
Shifting Out of NEUTRAL
To shift out of NEUTRAL do the following:
1. Set the parking brake and apply the regular
brake pedal.
2. Shift the transmission to NEUTRAL (N) and turn the
ignition to ON/RUN with the engine off.
3. Turn the transfer case dial to the desired transfer
case shift position (Two-Wheel Drive High,
Four-Wheel Drive High, AUTO).
After the transfer case has shifted out of NEUTRAL
the NEUTRAL light will go out.4. Release the parking brake prior to moving the
vehicle.
Notice:Shifting the transmission into gear before
the Four-Wheel Drive Low indicator light has
stopped ashing could damage the transfer case.
To help avoid damaging your vehicle, always
wait for the Four-Wheel Drive Low indicator light to
stop ashing before shifting the transmission
into gear.
5. Start the engine and shift the transmission to the
desired position.
Excessively shifting the transfer case into or out of the
different modes may cause the transfer case to
enter the shift protection mode. This will protect the
transfer case from possible damage and will only allow
the transfer case to respond to one shift per
10 seconds. The transfer case may stay in this mode for
up to three minutes.
2-42

Shifting Into PARK (P)
{CAUTION:
It can be 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. 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, use the steps that follow. With
four-wheel drive, if your transfer case is in
NEUTRAL, your vehicle will be free to roll,
even if your shift lever is in PARK (P). So, be
sure the transfer case is in a drive gear — not
in NEUTRAL. If you are pulling a trailer, see
Towing a Trailer on page 4-49.
1. Hold the brake pedal down with your right foot and
set the parking brake.
SeeParking Brake on page 2-43for more
information.2. Move the shift lever into the PARK (P) position by
pulling the shift lever toward you and moving it up
as far as it will go.
3. Be sure the transfer case is in a drive gear — not
in NEUTRAL (N).
4. Turn the ignition key to LOCK/OFF.
5. Remove the key and take it with you. If you can
leave your vehicle with the ignition key in your
hand, your vehicle is in PARK (P).
2-44

Leaving Your Vehicle With the Engine
Running
{CAUTION:
It can be dangerous to leave your vehicle with
the engine running. Your vehicle could move
suddenly if the shift lever is not fully in PARK
(P) with the parking brake rmly set.
If you have four-wheel drive and your transfer
case is in NEUTRAL, your vehicle will be free to
roll, even if your shift lever is in PARK (P). So be
sure the transfer case is in a drive gear — not in
NEUTRAL.
And, if you leave the vehicle with the engine
running, it could overheat and even catch re.
You or others could be injured. Do not leave
your vehicle with the engine running unless you
have to.If you have to leave your vehicle with the engine
running, be sure your vehicle is in PARK (P) and the
parking brake is rmly set before you leave it. After you
move the shift lever into PARK (P), hold the regular
brake pedal down. Then, see if you can move the shift
lever away from PARK (P) without rst pulling it
toward you. If you can, it means that the shift lever was
not fully locked into PARK (P).
Torque Lock
If you are parking on a hill and you do not shift your
transmission into PARK (P) properly, the weight of the
vehicle may put too much force on the parking pawl
in the transmission. You may nd it difficult to pull the
shift lever out of PARK (P). This is called torque lock. To
prevent torque lock, set the parking brake and then
shift into PARK (P) properly before you leave the driver’s
seat. To nd out how, seeShifting Into PARK (P) on
page 2-44.
When you are ready to drive, move the shift lever out of
PARK (P) before you release the parking brake.
If torque lock does occur, you may need to have another
vehicle push yours a little uphill to take some of the
pressure from the parking pawl in the transmission, then
you will be able to pull the shift lever out of PARK (P).
2-45

Shifting Out of PARK (P)
This vehicle is equipped with an electronic shift lock
release system. The shift lock release is designed to:
Prevent ignition key removal unless the shift
lever is in PARK (P) with the shift lever button fully
released, and
Prevent movement of the shift lever out of
PARK (P), unless the ignition is in ON/RUN or
ACC/ACCESSORY and the regular brake pedal
is applied.
The shift lock release is always functional except in the
case of an uncharged or low voltage (less than 9
volt) battery.
If your vehicle has an uncharged battery or a battery
with low voltage, try charging or jump starting the
battery. SeeJump Starting on page 5-46for more
information.
To shift out of PARK (P) use the following:
1. Apply the brake pedal.
2. Move the shift lever to the desired position.If you still are unable to shift out of PARK (P):
1. Ease the pressure on the shift lever.
2. While holding down the brake pedal, press the shift
lever all the way into PARK (P).
3. Move the shift lever to the desired position.
If you are still having a problem shifting, then have your
vehicle serviced soon.
Parking Over Things That Burn
{CAUTION:
Things that can burn could touch hot exhaust
parts under your vehicle and ignite. Do not
park over papers, leaves, dry grass, or other
things that can burn.
2-46

Temperature and Compass Display
Press the on/off button, located to the far left, briey to
turn the compass/temperature display on or off.
If the display reads CAL, the compass needs to be
calibrated. For more information, see “Compass
Calibration” following.
To adjust between Fahrenheit and Celsius:
1. Press and hold the on/off button for approximately
four seconds until either a ashing F or C appears.
2. Press the button again to change the display to the
desired unit of measurement. After approximately
four seconds of inactivity, the new unit will be locked
in and the compass/temperature display will
return.
If an abnormal temperature reading is displayed for an
extended period of time, see your dealer/retailer.
Under certain circumstances, a delay in updating the
temperature is normal.
Automatic Dimming Mirror Operation
The automatic dimming mirror comes on each time the
ignition is turned to start. To turn the automatic
dimming feature off or back on, press the on/off button.
The indicator light on the mirror is lit when the
automatic dimming feature is on.
Compass Calibration
The compass may need calibration if one of the
following occurs:
After approximately ve seconds, the display does
not show a compass heading, N for North, for
example, there may be a strong magnetic eld
interfering with the compass. Such interference may
be caused by a magnetic antenna mount, magnetic
note pad holder, or a similar magnetic item.
The compass does not display the correct heading
and the compass zone variance is set correctly.
In order to calibrate, CAL must be displayed in the
mirror compass windows. If CAL is not displayed, push
the on/off button for approximately 12 seconds or
until CAL is displayed.
The compass can be calibrated by driving the vehicle in
circles at 5 mph (8 km/h) or less until the display
reads a direction.
Compass Variance
The mirror is set in zone eight upon leaving the factory.
It will be necessary to adjust the compass to
compensate for compass variance if the vehicle is
outside of zone eight. Under certain circumstances, as
during a long distance cross-country trip, it will be
necessary to adjust for compass variance.
2-50