2005 GMC YUKON engine

To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord. The
cord is located on the driver’s side of the engine
compartment, near the power steering uid
reservoir.
3. Plug it into a normal, grounded 110-volt AC outlet.
{CAUTION:
Plugging the cord into an ungrounded outlet
could cause an electrical shock. Also, the
wrong kind of extension cord could overheat
and cause a re. You could be seriously
injured. Plug the cord into a properly grounded
three-prong 110-volt AC outlet. If the cord will
not reach, use a heavy-duty three-prong
extension cord rated for at least 15 amps.
4. Before starting the engine, be sure to unplug and
store the cord as it was before to keep it away
from moving engine parts. If you do not, it could be
damaged.How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature, the
kind of oil you have, and some other things. Instead
of trying to list everything here, we ask that you contact
your dealer in the area where you will be parking
your vehicle. The dealer can give you the best advice
for that particular area.
Automatic Transmission Operation
There are several different positions for your shift lever.
Your vehicle is equipped with an automatic transmission
and features an electronic shift position indicator
within the instrument panel cluster. This display must be
powered anytime the shift lever is capable of being
moved out of PARK (P).
2-23

PARK (P):This position locks your rear wheels. It is
the best position to use when you start your engine
because your vehicle cannot move easily.
{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). See
Shifting Into Park (P) on page 2-36. If you are
pulling a trailer, seeTowing a Trailer on
page 4-67.
{CAUTION:
If you have four-wheel drive, your vehicle will
be free to roll — even if your shift lever is in
PARK (P) — if your transfer case is in
NEUTRAL. So, be sure the transfer case is in a
drive gear, two-wheel high (2H) or four-wheel
high (4H) or four-wheel low (4L) — not in
NEUTRAL. SeeShifting Into Park (P) on
page 2-36.
REVERSE (R):Use this gear to back up.
Notice:Shifting to REVERSE (R) while your vehicle
is moving forward could damage the transmission.
The repairs would not be covered by your warranty.
Shift to REVERSE (R) only after your vehicle is
stopped.
To rock your vehicle back and forth to get out of snow,
ice or sand without damaging your transmission,
seeIf Your Vehicle is Stuck in Sand, Mud, Ice or Snow
on page 4-49.
2-24

NEUTRAL (N):In this position, your engine does not
connect with the wheels. To restart when you are
already moving, use NEUTRAL (N) only. Also, use
NEUTRAL (N) when your two-wheel drive vehicle
is being towed.
{CAUTION:
Shifting into a drive gear while your engine is
running at high speed is dangerous. Unless
your foot is rmly on the brake pedal, your
vehicle could move very rapidly. You could
lose control and hit people or objects. Do not
shift into a drive gear while your engine is
running at high speed.
Notice:Shifting out of PARK (P) or NEUTRAL (N)
with the engine running at high speed may damage
the transmission. The repairs would not be
covered by your warranty. Be sure the engine is not
running at high speed when shifting your vehicle.DRIVE (D):This position is for normal driving. If you
need more power for passing, and you are:
Going less than about 35 mph (56 km/h), push your
accelerator pedal about halfway down.
Going about 35 mph (56 km/h) or more, push the
accelerator all the way down.
You will shift down to the next gear and have 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 may want to shift the transmission to
THIRD (3) or, if necessary, a lower gear selection if the
transmission shifts too often.
THIRD (3):This position is also used for normal driving,
however it offers more power and lower fuel economy
than DRIVE (D).
SECOND (2):This position gives you more power but
lower fuel economy. 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 your brakes off and on.
If you manually select SECOND (2) in a light duty
automatic transmission, the transmission will drive in
second gear. You may 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.
2-25

FIRST (1):This position gives you even more power
(but lower fuel economy) than SECOND (2). 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 will not shift into rst
gear until the vehicle is going slowly enough.
Notice:Spinning the tires or holding the vehicle in
one place on a hill using only the accelerator
pedal may damage the transmission. If you are
stuck, do not spin the tires. When stopping on a hill,
use the brakes to hold the vehicle in place.
On cold days, approximately 32°F (0°C) or colder, your
transmission is designed to shift differently until the
engine reaches normal operating temperature. This is
intended to improve heater performance.Tow/Haul Mode
Your vehicle may be equipped with a Tow/Haul mode.
If so, 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. SeeTowing a
Trailer on page 4-67for more information.
2-26

When Tow/Haul mode is
selected the Tow/Haul
indicator light will
illuminate.
The Tow/Haul mode also interacts with the Autoride
®™
feature, if equipped, to enhance the ride when
trailering or with a loaded vehicle. SeeAutoride
®on
page 4-66.
Four-Wheel Drive
If your vehicle has four-wheel drive, you will see the
buttons shown below. You can send your engine’s
driving power to all four wheels for extra traction. To get
the most satisfaction out of four-wheel drive, you
must be familiar with its operation. Read the part that
follows before using four-wheel drive.
Notice:Driving on clean, dry pavement in
four-wheel drive 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 for extended periods of time.The transfer case buttons
are located to the left of
the instrument panel
cluster.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.
2-27

Indicator lights in the button show which setting you are
in. The indicator lights will come on briey when you
turn on the ignition and one will stay on. If the lights do
not come on, you should take your vehicle to your
dealer for service. An indicator light will ash while
shifting the transfer case. It will remain illuminated when
the shift is complete. If for some reason the transfer
case cannot make a requested shift, it will return to the
last chosen setting.
If the SERVICE 4WD message stays on, you should
take your vehicle to your dealer for service. See “Service
4WD message” underDriver Information Center (DIC)
on page 3-54.
Shifting Into Four-Wheel High or AUTO
4WD (Automatic Four Wheel Drive)
Press and release the Four-Wheel High or automatic
four wheel drive button. This can be done at any speed,
except when shifting from Four Wheel-Low, and the
indicator light will ash while shifting. It will remain on
when the shift is completed.
Shifting Into Two-Wheel High
Press and release the Two-Wheel High button. This can
be done at any speed, except when shifting from
Four-Wheel Low.
Shifting Into Four-Wheel Low
To shift to the Four-Wheel Low position, the ignition
must be in RUN and the vehicle must be stopped
or moving less than 3 mph (5 km/h) with the
transmission in NEUTRAL (N). The preferred method for
shifting into four-wheel low is to have your vehicle
moving 1 to 2 mph (1.6 to 3.2 km/h). Press and release
the Four-Wheel Low button. You must wait for the
four-wheel low indicator light to stop ashing and remain
on before shifting your transmission in gear.
Notice:Shifting the transmission into gear before
the Four-Wheel Low indicator light has stopped
ashing could damage the transfer case. To help
avoid damaging your vehicle, always wait for the
Four-Wheel Low indicator light to stop ashing
before shifting the transmission into gear.
It is typical for your vehicle to exhibit signicant
engagement noise and bump when shifting between
Four-Wheel Low and Four-Wheel High ranges or from
NEUTRAL with the engine running.
If the Four-Wheel Low button is pressed when your
vehicle is in gear and/or moving, the Four-Wheel Low
indicator light will ash for 30 seconds and not complete
the shift unless your vehicle is moving less than
3 mph (5 km/h) and the transmission is in NEUTRAL (N).
After 30 seconds the transfer case will shift to
Four-Wheel High mode.
2-29

Shifting Out of Four-Wheel Low
To shift from Four-Wheel Low to Four-Wheel High, AUTO
4WD or Two-Wheel 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 RUN. The preferred
method for shifting out of Four-Wheel Low is to have your
vehicle moving 1 to 2 mph (1.6 to 3.2 km/h). Press and
release the Four-Wheel High, AUTO 4WD or Two-Wheel
High button. You must wait for the Four-Wheel High,
AUTO 4WD or Two-Wheel 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 Low indicator light has stopped
ashing could damage the transfer case. To
help avoid damaging your vehicle, always wait for
the Four-Wheel Low indicator light to stop ashing
before shifting the transmission into gear.
It is typical for your vehicle to exhibit signicant
engagement noise and bump when shifting between
Four-Wheel Low and Four-Wheel High ranges or from
NEUTRAL with the engine running.
If the Four-Wheel High, AUTO 4WD or Two Wheel High
switch is pressed when your vehicle is in gear and/or
moving, the Four-Wheel High, AUTO 4WD or Two-Wheel
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.
3. Start the vehicle or turn the ignition to RUN.
4. Put the transmission in NEUTRAL (N).
5. Shift the transfer case to Two-Wheel High.
6. Simultaneously press and hold the Two-Wheel High
and Four-Wheel Low buttons for 10 seconds. The
NEUTRAL light will come on when the transfer case
shift to NEUTRAL is complete.
7. If the engine is running, verify that the transmission
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 ACCESSORY, which will turn
the engine off.
9. Place the transmission shift lever in PARK (P).
10. Turn the ignition to LOCK.
2-30

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 RUN with the engine off.
3. Press the button for the desired transfer case shift
position (Two-Wheel High, Four-Wheel High, AUTO
4WD, or Four-Wheel Low).
4. After the transfer case has shifted out of NEUTRAL
the NEUTRAL light will go out.
5. Release the parking brake.
6. 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.
All-Wheel Drive with StabiliTrak®
If your vehicle has this system, you will see the buttons
shown below. With this system, engine power is sent
to all four wheels when you select the AWD button.
The transfer case buttons
are located to the left of
the instrument panel
cluster. Use these buttons
to shift between the
various modes of
four-wheel drive.
All-wheel drive is like four-wheel drive, but there is
no separate lever or switch to engage or disengage
the front axle. It is fully automatic, and when combined
with StabiliTrak
®, the all-wheel drive system adjusts
itself as needed for road conditions.
2-31