2011 GMC YUKON engine

Black plate (36,1)GMC Yukon/Yukon XL Owner Manual - 2011
9-36 Driving and Operating
Engine Exhaust
{WARNING
Engine exhaust contains carbon
monoxide (CO) which cannot be
seen or smelled. Exposure to CO
can cause unconsciousness and
even death.
Exhaust may enter the vehicle if:
.The vehicle idles in areas
with poor ventilation (parking
garages, tunnels, deep snow
that may block underbody
airflow or tail pipes).
.The exhaust smells or
sounds strange or different.
.The exhaust system leaks
due to corrosion or damage.
.The vehicle exhaust system
has been modified, damaged
or improperly repaired.(Continued)
WARNING (Continued)
.There are holes or openings
in the vehicle body from
damage or after market
modifications that are not
completely sealed.
If unusual fumes are detected or
if it is suspected that exhaust is
coming into the vehicle:
.Drive it only with the windows
completely down.
.Have the vehicle repaired
immediately.
Never park the vehicle with the
engine running in an enclosed
area such as a garage or a
building that has no fresh air
ventilation.
Running the Vehicle
While Parked
It is better not to park with the
engine running. But if you ever have
to, here are some things to know.
{WARNING
Idling a vehicle in an enclosed
area with poor ventilation is
dangerous. Engine exhaust may
enter the vehicle. Engine exhaust
contains carbon monoxide (CO)
which cannot be seen or smelled.
It can cause unconsciousness
and even death. Never run the
engine in an enclosed area that
has no fresh air ventilation. For
more information, see Engine
Exhaust on page 9‑36.

Black plate (37,1)GMC Yukon/Yukon XL Owner Manual - 2011
Driving and Operating 9-37
{WARNING
It can be dangerous to get out
of the vehicle if the automatic
transmission shift lever is not fully
in P (Park) with the parking brake
firmly set. The vehicle can roll. Do
not leave the 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 the
vehicle will not move, even when
you are on fairly level ground,
always set the parking brake and
move the shift lever to P (Park).
{WARNING
If the vehicle has a four-wheel
drive transfer case with a
N (Neutral) position, and the
transfer case is in N (Neutral),
the vehicle may roll, even if the
automatic transmission shift
lever is in P (Park). So, be sure
the transfer case is in a drive
gear—not in N (Neutral). Always
set the parking brake.
Follow the proper steps to be sure
the vehicle will not move. See
Shifting Into Park on page 9‑33.
If parking on a hill and pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9‑75.
Automatic
Transmission
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
If the vehicle is has an automatic
transmission, it has an electronic
shift position indicator within the
instrument panel cluster. This
display comes on when the ignition
key is turned to the ON/RUN
position.
There are several different positions
for the shift lever.
Heavy Duty 6-Speed Automatic
Transmission Shown (Light Duty Similar)
See “Range Selection Mode” under
Manual Mode on page 9‑41.

Black plate (38,1)GMC Yukon/Yukon XL Owner Manual - 2011
9-38 Driving and Operating
P (Park):This position locks the
rear wheels. It is the best position
to use when starting the engine
because the 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
P (Park). See “Torque Lock” under
Shifting Into Park on page 9‑33 for
more information.
{WARNING
It is dangerous to get out of the
vehicle if the shift lever is not fully
in P (Park) with the parking brake
firmly set. The vehicle can roll.
Do not leave the 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 the
vehicle will not move, even when
you are on fairly level ground,
(Continued)
WARNING (Continued)
always set the parking brake and
move the shift lever to P (Park).
SeeShifting Into Park on
page 9‑33. If you are pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9‑75.
{WARNING
If the vehicle has a four-wheel
drive transfer case with a
N (Neutral) position, and the
transfer case is in N (Neutral), the
vehicle will be free to roll —even
if the shift lever is in P (Park).
Be sure the transfer case is in a
drive gear, Two-Wheel Drive High
or Four-Wheel Drive High or
Four-Wheel Drive Low —not in
N (Neutral). See Shifting Into Park
on page 9‑33. Always set the
parking brake. R (Reverse):
Use this gear to
back up.
Notice: Shifting to R (Reverse)
while the vehicle is moving
forward could damage the
transmission. The repairs would
not be covered by the vehicle
warranty. Shift to R (Reverse) only
after the vehicle is stopped.
To rock the vehicle back and forth to
get out of snow, ice, or sand without
damaging the transmission, see If
the Vehicle is Stuck on page 9‑22.
N (Neutral): In this position, the
engine does not connect with the
wheels. To restart the engine when
the vehicle is already moving,
use N (Neutral) only. Also, use
N (Neutral) when the vehicle is
being towed.

Black plate (39,1)GMC Yukon/Yukon XL Owner Manual - 2011
Driving and Operating 9-39
{WARNING
Shifting into a drive gear while the
engine is running at high speed is
dangerous. Unless your foot is
firmly on the brake pedal, the
vehicle could move very rapidly.
You could lose control and hit
people or objects. Do not shift
into a drive gear while the engine
is running at high speed.
Notice: Shifting out of P (Park)
or N (Neutral) with the engine
running at high speed may
damage the transmission. The
repairs would not be covered by
the vehicle warranty. Be sure the
engine is not running at high
speed when shifting the vehicle. D (Drive):
This position is for
normal driving. It provides the best
fuel economy. If you need more
power for passing, and you are:
.Going less than about 55 km/h
(35 mph), push the accelerator
pedal about halfway down.
.Going about 55 km/h (35 mph) or
more, push the accelerator all
the way down.
By doing this, the vehicle shifts
down to the next gear and has
more power.
D (Drive) 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 9‑6. The 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.
The 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.

Black plate (40,1)GMC Yukon/Yukon XL Owner Manual - 2011
9-40 Driving and Operating
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 the
temperature changes. During this
adaptive shift control process,
shifting might feel different as the
transmission determines the best
settings.
When temperatures are very cold,
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.
M (Manual Mode):This position
lets drivers select the range of gears
appropriate for current driving
conditions. If the vehicle has this
feature, see “Range Selection
Mode” underManual Mode on
page 9‑41. 3 (Third):
This position is also used
for normal driving. It reduces vehicle
speed more than D (Drive) without
using the brakes. You might choose
3 (Third) instead of D (Drive) when
driving on hilly, winding roads, when
towing a trailer, so there is less
shifting between gears and when
going down a steep hill.
2 (Second): This position reduces
vehicle speed even more than
3 (Third) without using the brakes.
You can use 2 (Second) on hills.
It can help control vehicle 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 2 (Second)
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 the vehicle from a stop on
slippery road surfaces. 1 (First):
This position reduces
vehicle speed without using the
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 1 (First) it provides the lowest
gear appropriate to the vehicle's
current road speed and continues
to downshift as the vehicle slows,
eventually downshifting to
1 (First) 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 the vehicle
warranty. If you are stuck, do not
spin the tires. When stopping on
a hill, use the brakes to hold the
vehicle in place.

Black plate (42,1)GMC Yukon/Yukon XL Owner Manual - 2011
9-42 Driving and Operating
Tow/Haul Mode
The 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
Equipment on page 9‑84 for 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.
See Continuous Damping Control
(CDC) on page 9‑55.
Grade Braking (Hydra-Matic®
6-Speed Automatic
Transmission)
The Grade Braking shift modes can
be activated by pressing the button
on the end of the shift control lever.
While in Range Selection Mode,
Grade Braking is deactivated
allowing the driver to select a
desired range of gears.
Grade Braking is only active while
the Tow/Haul Mode is selected and
you are not in the Range Selection
Mode. See “Tow/Haul Mode” listed
previously and Manual Mode on
page 9‑41 for more information on
the Range Selection Mode. Grade
Braking assists in maintaining
desired vehicle speeds when driving on downhill grades by automatically
implementing a shift schedule that
utilizes the engine and transmission
to slow the vehicle. This reduces
wear on the braking system and
increases control of the vehicle.
Grade Braking monitors vehicle
speed, acceleration, engine torque
and brake pedal usage. Using this
information, it detects when the
truck is on a downhill grade and the
driver desires to slow the vehicle by
pressing the brake.
Also see
Towing Equipment on
page 9‑84 for more information.
Cruise Grade Braking
(Hydra-Matic®6-Speed
Automatic Transmission)
Cruise Grade Braking assists
when driving on a downhill grade.
It maintains vehicle speed by
automatically implementing a shift
schedule that uses the engine and
the transmission to slow the vehicle.

Black plate (43,1)GMC Yukon/Yukon XL Owner Manual - 2011
Driving and Operating 9-43
Cruise Grade Braking operates
while Cruise Control is engaged
in Tow/Haul Mode to assist in
maintaining vehicle speed under
loaded vehicle conditions. It utilizes
vehicle acceleration and deviation
from desired speed to determine
the correct gear for the operating
condition. If vehicle speed is above
the desired speed the transmission
will downshift to slow the vehicle.
If vehicle speed is near or below
desired speed the trans will upshift,
allowing vehicle speed to increase.
While in the Range Selection
Mode, Cruise Grade Braking is not
available.
See“Range Selection Mode” under
Manual Mode on page 9‑41.Drive Systems
Four-Wheel Drive (Two
Speed Automatic
Transfer Case)
If the vehicle has four-wheel drive,
you can send the engine's driving
power to all four wheels for extra
traction. Read the following 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 the
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.
The vehicle has StabiliTrak
®.
Shifting into Four-Wheel Drive
Low will turn Traction Control and
StabiliTrak off. See StabiliTrak
®
System on page 9‑52.
Front Axle
The front axle engages and
disengages automatically when you
shift the transfer case. Some delay
for the axle to engage or disengage
is normal.

Black plate (46,1)GMC Yukon/Yukon XL Owner Manual - 2011
9-46 Driving and Operating
To shift to the Four-Wheel Drive
Low position, the ignition must be in
ON/RUN and the vehicle must be
stopped or moving less than 5 km/h
(3 mph) with the transmission in
N (Neutral). The preferred method
for shifting into Four-Wheel Drive
Low is to have the vehicle moving
1.6 to 3.2 km/h (1 to 2 mph). Turn
the knob to the Four-Wheel Drive
Low position. You must wait for the
Four-Wheel Drive Low indicator
light to stop flashing and remain on
before shifting the transmission
into gear.
Notice:Shifting the transmission
into gear before the Four-Wheel
Drive Low indicator light has
stopped flashing could damage
the transfer case. To help avoid
damaging the vehicle, always wait
for the Four-Wheel Drive Low
indicator light to stop flashing
before shifting the transmission
into gear. The vehicle may have significant
engagement noise and bump when
shifting between Four-Wheel Drive
Low and Four-Wheel Drive High
ranges or from N (Neutral) while the
engine is running.
If the knob is turned to the
Four-Wheel Drive Low position
when the vehicle is in gear and/or
moving more than 1.6 to 3.2 km/h
(1 to 2 mph), the Four-Wheel Drive
Low indicator light will flash for
30 seconds and not complete the
shift. After 30 seconds the transfer
case will shift to Four-Wheel Drive
High mode. With the vehicle moving
less than 5 km/h (3 mph) and the
transmission in N (Neutral), attempt
the shift again.
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,
the vehicle must be stopped or
moving less than 5 km/h (3 mph)
with the transmission in N (Neutral)and the ignition in ON/RUN. The
preferred method for shifting out of
Four-Wheel Drive Low is to have
your vehicle moving 1.6 to 3.2 km/h
(1 to 2 mph). 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
flashing and remain on before
shifting the transmission into gear.
Notice:
Shifting the transmission
into gear before the Four-Wheel
Drive Low indicator light has
stopped flashing could damage
the transfer case. To help avoid
damaging the vehicle, always wait
for the Four-Wheel Drive Low
indicator light to stop flashing
before shifting the transmission
into gear.
The vehicle may have significant
engagement noise and bump when
shifting between Four-Wheel Drive
Low and Four-Wheel Drive High
ranges or from N (Neutral) while the
engine is running.