2010 GMC ACADIA transmission

9-20 Driving and Operating
If you can, it means that the shift
lever was not fully locked in
P (Park).
Torque Lock
Torque lock is when the weight of
the vehicle puts too much force on
the parking pawl in the
transmission. This happens when
parking on a hill and shifting the
transmission into P (Park) is not
done properly and then it is difficult
to shift out of P (Park). To prevent
torque lock, set the parking brake
and then shift into P (Park). To find
out how, see“Shifting Into Park”
listed previously.
If torque lock does occur, your
vehicle may need to be pushed
uphill by another vehicle to relieve
the parking pawl pressure, so you
can shift out of P (Park).
Shifting Out of Park
The 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
P (Park) with the shift lever
button fully released, and
.Prevent movement of the shift
lever out of P (Park), 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 the vehicle has an uncharged
battery or a battery with low voltage,
try charging or jump starting the
battery. See Jump Starting
on
page 10‑78for more information. To shift out of P (Park):
1. Apply the brake pedal.
2. Press the shift lever button.
3. Move the shift lever to the
desired position.
If you still are unable to shift out of
P (Park):
1. Fully release the shift lever button.
2. While holding down the brake pedal, press the shift lever
button again.
3. Move the shift lever to the desired position.
If you still cannot move the shift
lever from P (Park), see your dealer/
retailer.

9-22 Driving and Operating
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, seeEngine
Exhaust on page 9‑21.
{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).
Follow the proper steps to be sure
the vehicle will not move. See
Shifting Into Park on page 9‑19.
If parking on a hill and pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9‑44.
Automatic
Transmission
The automatic transmission has a
shift lever located on the console
between the seats.
P (Park): This position locks the
front wheels. It is the best position
to use when starting the engine
because the vehicle cannot move
easily.

Driving and Operating 9-23
{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,
always set the parking brake and
move the shift lever to P (Park).
SeeShifting Into Park
on
page 9‑19
. If you are pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9‑44.
Make sure the shift lever is fully in
P (Park) before starting the engine.
The vehicle has an automatic
transmission shift lock control system. You must fully apply the
regular brake first and then press
the shift lever button before shifting
from P (Park) when the ignition key
is in ON/RUN. If you cannot shift out
of P (Park), ease pressure on the
shift lever, then push the shift lever
all the way into P (Park) as you
maintain brake application. Then
press the shift lever button and
move the shift lever into another
gear. See
Shifting Out of Park
on
page 9‑20.
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 9‑10. 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.
{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.

9-24 Driving and Operating
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 56 km/h
(35 mph), push the accelerator
pedal about halfway down.
.Going about 56 km/h (35 mph) or
more, push the accelerator all
the way down.
Notice: If the vehicle seems to
accelerate slowly or not shift
gears when you go faster, and
you continue to drive the vehicle
that way, you could damage the
transmission. Have the vehicle
serviced right away. You can
drive in L (Low) when you are
driving less than 56 km/h (35 mph)
and D (Drive) for higher speeds
until then.
L (Low): This position gives you
access to gear ranges. This
provides more engine braking but
lower fuel economy than D (Drive).
You can use it on very steep hills,
or in deep snow or mud.
Manual Mode
Electronic Range Select
(ERS) Mode
ERS mode allows you to choose the
top-gear limit of the transmission
and the vehicle's speed while
driving down hill or towing a trailer.
The vehicle has an electronic shift
position indicator within the
instrument panel cluster. When
using the ERS Mode a number will
display next to the L, indicating the
current gear that has been selected.
To use this feature:
1. Move the shift lever to L (Low).
2. Press the plus/minus button located on the shift lever, to
increase or decrease the gear
range available.
When you shift from D (Drive) to
L (Low), the transmission will shift to
a pre-determined lower gear range.
The highest gear available for this
pre-determined range is displayed
next to the L in the DIC. See DriverInformation Center (DIC) (With DIC
Buttons)
on page 5‑28or
Driver
Information Center (DIC) (Without
DIC Buttons)
on page 5‑28for
more information. The number
displayed in the DIC is the highest
gear that the transmission will be
allowed to operate in. This means
that all gears below that number are
available. For example, when
4 (Fourth) is shown next to the L,
1 (First) through 4 (Fourth) gears are
automatically shifted by the vehicle.
The transmission will not shift into
5 (Fifth) until the + (Plus) button is
used or you shift back into D (Drive).
While in L (Low), the transmission
will prevent shifting to a lower gear
range if the engine speed is too
high. You have a brief period of time
to slow the vehicle. If vehicle speed
is not reduced within the time
allowed, the lower gear range shift
will not be completed. You must
further slow the vehicle, then press
the −(Minus) button to the desired
lower gear range.

Driving and Operating 9-25
Automatic Engine Grade braking is
not available when the ERS is
active. It is available in D (Drive) for
both normal and Tow/Haul mode.
While using the ERS, cruise control
and the tow/haul mode can be used.
See Tow/Haul Mode following.
Tow/Haul Mode
_
(Tow/Haul):The vehicle may
have a Tow/Haul mode.
The button is located on the
instrument panel under the climate
controls.
Push the button to activate the
system. Push it again to deactivate
the system. You can use this feature
to assist when towing or hauling a
heavy load.
When Tow/Haul is activated the
Tow/Haul symbol will come on the
instrument panel cluster. See “Tow/
Haul Mode” underDriving
Characteristics and Towing Tips
on
page 9‑44for more information.
Automatic Engine Grade
Braking
Automatic Engine 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.
The system will automatically
command downshifts to reduce
vehicle speed, until the brake pedal
is no longer being pressed.
While in the Electronic Range
Select (ERS) mode, grade braking
is deactivated, allowing the driver to
select a range and limiting the
highest gear available. Grade
braking is available for normal
driving and in Tow/Haul mode.
See Automatic Transmission
on
page 9‑22.
Drive Systems
All-Wheel Drive
With this feature, engine power is
always sent to all four wheels. It is
fully automatic, and adjusts itself as
needed for road conditions.
When using a compact spare tire on
an AWD vehicle, the system
automatically detects the compact
spare and disables AWD. To restore
AWD operation and prevent
excessive wear on system, replace
the compact spare with a full-size
tire as soon as possible. See
Compact Spare Tire
on page 10‑77for more information.

Driving and Operating 9-29
Traction control can be turned on by
pressing and releasing the traction
control disable button if not
automatically shut off for any other
reason.
When the traction control system is
turned off, the StabiliTrak light and
the appropriate traction control off
message will be displayed on the
DIC to warn the driver. The vehicle
will still have brake-traction control
when traction control is off, but will
not be able to use the engine speed
management system. See“Traction
Control Operation” next for more
information.
When the traction control system
has been turned off, system noises
may be heard and felt as a result of
the brake-traction control working.
It is recommended to leave the
system on for normal driving
conditions, but it may be necessary
to turn the system off if the vehicle
is stuck in sand, mud, ice or snow, and you want to
“rock”the vehicle to
attempt to free it. It may also be
necessary to turn off the system
when driving in extreme off-road
conditions where high wheel spin is
required. See If the Vehicle is Stuck
on page 9‑10.
Traction Control Operation
The traction control system is part of
the StabiliTrak system. Traction
control limits wheel spin by reducing
engine power to the wheels (engine
speed management) and by
applying brakes to each individual
wheel (brake-traction control) as
necessary.
The traction control system is
enabled automatically when the
vehicle is started. It will activate and
the StabiliTrak light will flash if it
senses that any of the wheels are
spinning or beginning to lose
traction while driving. If traction
control is turned off, only the
brake-traction control portion of
traction control will work. The
engine speed management will be disabled. In this mode, engine
power is not reduced automatically
and the driven wheels can spin
more freely. This can cause the
brake-traction control to activate
constantly.
Notice:
If the wheel(s) of one axle
is allowed to spin excessively
while the StabiliTrak, ABS and
brake warning lights and any
relevant DIC messages are
displayed, the transfer case could
be damaged. The repairs would
not be covered by the vehicle
warranty. Reduce engine power
and do not spin the wheel(s)
excessively while these lights and
messages are displayed.
The traction control system may
activate on dry or rough roads or
under conditions such as heavy
acceleration while turning or abrupt
upshifts/downshifts of the
transmission. When this happens, a
reduction in acceleration may be
noticed, or a noise or vibration may
be heard. This is normal.

9-44 Driving and Operating
Towing
General Towing
Information
Only use towing equipment that has
been designed for the vehicle.
Contact your dealer/retailer or
towing retailer for assistance with
preparing the vehicle for towing a
trailer.
See the following trailer towing
information in this section:
.For information on driving while
towing a trailer, see Driving
Characteristics and Towing Tips.
.For maximum vehicle and trailer
weights, see Trailer Towing.
.For information on equipment to
tow a trailer, see Towing
Equipment.For information on towing a disabled
vehicle, see
Towing the Vehicle
on
page 10‑82. For information on
towing the vehicle behind another
vehicle —such as a motorhome,
see Recreational Vehicle Towing
on
page 10‑82.
Driving Characteristics
and Towing Tips
{WARNING
The driver can lose control when
pulling a trailer if the correct
equipment is not used or the
vehicle is not driven properly. For
example, if the trailer is too
heavy, the brakes may not work
well —or even at all. The driver
and passengers could be
seriously injured. The vehicle may
also be damaged; the resulting
(Continued)
WARNING (Continued)
repairs would not be covered by
the vehicle warranty. Pull a trailer
only if all the steps in this section
have been followed. Ask your
dealer/retailer for advice and
information about towing a trailer
with the vehicle.
The vehicle can tow a trailer when
equipped with the proper trailer
towing equipment. For trailering
capacity, see Trailer Towing
on
page 9‑49. Trailering changes
handling, acceleration, braking,
durability and fuel economy. With
the added weight, the engine,
transmission, wheel assemblies and
tires are forced to work harder and
under greater loads. The trailer also
adds wind resistance, increasing the
pulling requirements. For safe
trailering, correctly use the proper
trailering equipment.

Driving and Operating 9-45
The following information has
important trailering tips and rules for
your safety and that of your
passengers. Read this section
carefully before pulling a trailer.
Pulling A Trailer
Here are some important points:
.There are many laws, including
speed limit restrictions that apply
to trailering. Check for legal
requirements with state or
provincial police.
.Consider using sway control.
SeeTowing Equipmenton
page 9‑53.
.Do not tow a trailer at all during
the first 800 km (500 miles) the
new vehicle is driven. The
engine, axle or other parts could
be damaged.
.During the first 800 km
(500 miles) that a trailer is
towed, do not drive over 80 km/h
(50 mph) and do not make starts
at full throttle. This reduces wear
on the vehicle.
.The vehicle can tow in D (Drive).
Use a lower gear if the
transmission shifts too often.
See “Tow/Haul Mode” later in
this section.
.Obey speed limit restrictions
when towing a trailer.
.The vehicle is designed primarily
as a passenger and load
carrying vehicle. If a trailer is
towed, the vehicle will require
more frequent maintenance due
to the additional load.
Driving with a Trailer
Towing a trailer requires experience.
Get familiar with handling and
braking with the added trailer
weight. The vehicle is now longer
and not as responsive as the
vehicle is by itself. Check all trailer hitch parts and
attachments, safety chains,
electrical connectors, lamps, tires
and mirror adjustments. If the trailer
has electric brakes, start the vehicle
and trailer moving and then apply
the trailer brake controller by hand
to be sure the brakes are working.
During the trip, check regularly to be
sure that the load is secure, and the
lamps and trailer brakes are working
properly.
Towing with a Stability Control
System
When towing, the sound of the
stability control system might be
heard. The system is reacting to the
vehicle movement caused by the
trailer, which mainly occurs during
cornering. This is normal when
towing heavier trailers.