2012 GMC ACADIA automatic transmission

Black plate (26,1)GMC Acadia/Acadia Denali Owner Manual - 2012
9-26 Driving and Operating
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. SeeDriver
Information Center (DIC) (Without
DIC Buttons) on page 5‑30 orDriver
Information Center (DIC) (With DIC
Buttons) on page 5‑25 for 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.
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 9‑45 for more information.

Black plate (27,1)GMC Acadia/Acadia Denali Owner Manual - 2012
Driving and Operating 9-27
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.
SeeAutomatic Transmission on
page 9‑23.
Drive Systems
All-Wheel Drive
Vehicles with this feature always
send engine power 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 the system,
replace the compact spare with a
full-size tire as soon as possible.
See Compact Spare Tire on
page 10‑77 for more information.
Brakes
Antilock Brake
System (ABS)
This vehicle has the Antilock Brake
System (ABS), an advanced
electronic braking system that helps
prevent a braking skid.
When the engine is started and the
vehicle begins to drive away, ABS
checks itself. A momentary motor or
clicking noise might be heard while
this test is going on, and it might
even be noticed that the brake
pedal moves a little. This is normal.
If there is a problem with ABS, this
warning light stays on. See Antilock
Brake System (ABS) Warning Light
on page 5‑22.

Black plate (31,1)GMC Acadia/Acadia Denali Owner Manual - 2012
Driving and Operating 9-31
system. See“Traction Control
Operation” following 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 the brakes 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, 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.
If cruise control is being used when
the system activates, the StabiliTrak
light will flash and cruise control will
automatically disengage. Cruise
control may be reengaged when
road conditions allow. See
Cruise
Control on page 9‑32.
StabiliTrak may also turn off
automatically if it determines that a
problem exists with the system.
If the problem does not clear itself
after restarting the vehicle, see your
dealer for service.

Black plate (47,1)GMC Acadia/Acadia Denali Owner Manual - 2012
Driving and Operating 9-47
.Improve control of vehicle speed
while requiring less throttle pedal
activity.
.Increase the charging system
voltage to assist in recharging a
battery installed in a trailer.
Press this button located on the
console to turn on and turn off the
Tow/Haul mode. SeeTow/Haul
Mode on page 9‑26.
The Tow/Haul light on the
instrument panel comes on to
indicate that Tow/Haul mode has
been selected.
Tow/Haul may be turned off by
pressing the button again, at which
time the indicator light on the
instrument panel will turn off.
The vehicle will automatically turn
off Tow/Haul every time it is started. Tow/Haul is designed to be most
effective when the vehicle and
trailer combined weight is at least
75 percent of the vehicle's Gross
Combined Weight Rating (GCWR).
See
Trailer Towing on page 9‑49.
Tow/Haul is most useful when
pulling a heavy trailer or a large or
heavy load under the following
driving conditions:
.Traveling through rolling terrain.
.Traveling in stop and go traffic.
.Traveling in busy parking lots
where improved low speed
control of the vehicle is desired.
Operating the vehicle in Tow/Haul
when lightly loaded or with no trailer
will not cause damage but there is
no benefit. Such a selection when
unloaded may result in unpleasant
engine and transmission driving
characteristics and reduced fuel
economy.
Following Distance
Stay at least twice as far behind the
vehicle ahead as you would when
driving the vehicle without a trailer.
This can help to avoid situations
that require heavy braking and
sudden turns.
Passing
More passing distance is needed
when towing a trailer. Because the
rig is longer, it is necessary to go
farther beyond the passed vehicle
before returning to the lane.
Backing Up
Hold the bottom of the steering
wheel with one hand. To move
the trailer to the left, move that
hand to the left. To move the trailer
to the right, move your hand to
the right. Always back up slowly
and, if possible, have someone
guide you.

Black plate (48,1)GMC Acadia/Acadia Denali Owner Manual - 2012
9-48 Driving and Operating
Making Turns
Notice:Making very sharp turns
while trailering could cause the
trailer to come in contact with the
vehicle. The vehicle could be
damaged. Avoid making very
sharp turns while trailering.
When turning with a trailer, make
wider turns than normal so the
trailer will not strike soft shoulders,
curbs, road signs, trees or other
objects. Use the turn signal well in
advance and avoid jerky or sudden
maneuvers.
Turn Signals When Towing a
Trailer
The turn signal indicators on the
instrument panel flash whenever
signaling a turn or lane change.
Properly hooked up, the trailer
lamps also flash, telling other
drivers the vehicle is turning,
changing lanes or stopping. When towing a trailer, the arrows on
the instrument panel flash for turns
even if the bulbs on the trailer are
burned out. Check occasionally to
be sure the trailer bulbs are still
working.
Driving on Grades
Reduce speed and shift to a lower
gear before starting down a long or
steep downgrade. If the
transmission is not shifted down, the
brakes might have to be used
so much that they would get hot and
no longer work well. See
“Automatic
Engine Grade Braking” within
Tow/Haul Mode on page 9‑26.
The vehicle can tow in D (Drive).
Use a lower gear if the transmission
shifts too often.
When towing at high altitude on
steep uphill grades, engine coolant
will boil at a lower temperature than
at normal altitudes. If the engine is
turned off immediately after towing
at high altitude on steep uphill
grades, the vehicle may show
signs similar to engine overheating. To avoid this, let the engine run
while parked, preferably on level
ground, with the transmission in
P (Park) for a few minutes before
turning the engine off. If the
overheat warning comes on, see
Engine Overheating on page 10‑18.
On a long uphill grade, shift down
and reduce the vehicle speed to
around 88 km/h (55 mph) to reduce
the possibility of the engine and the
transmission overheating.
Parking on Hills
{WARNING
Parking the vehicle on a hill
with the trailer attached can be
dangerous. If something goes
wrong, the rig could start to move.
People can be injured, and both
the vehicle and the trailer can be
damaged. When possible, always
park the rig on a flat surface.

Black plate (49,1)GMC Acadia/Acadia Denali Owner Manual - 2012
Driving and Operating 9-49
If parking the rig on a hill:
1. Press the brake pedal, butdo not shift into P (Park) yet.
Turn the wheels into the curb if
facing downhill or into traffic if
facing uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the brake pedal
until the chocks absorb the load.
4. Reapply the brake pedal. Then apply the parking brake
and shift into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal while you:
1.1. Start the engine.
1.2. Shift into a gear.
1.3. Release the parking brake.
2. Let up on the brake pedal. 3. Drive slowly until the trailer is
clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer
Towing
The vehicle needs service more
often when pulling a trailer.
See Maintenance Schedule on
page 11‑3. Things that are
especially important in trailer
operation are automatic
transmission fluid, engine oil, axle
lubricant, belts, cooling system and
brake system. Inspect these before
and during the trip.
Check periodically to see that all
hitch nuts and bolts are tight.
Engine Cooling When Trailer
Towing
The cooling system may temporarily
overheat during severe operating
conditions. See Engine Overheating
on page 10‑18.
Trailer Towing
Three important considerations
have to do with weight:
.The weight of the trailer
.The weight of the trailer tongue
.The total weight on the vehicle's
tires
Weight of the Trailer
How heavy can a trailer safely be?
Speed, altitude, road grades,
outside temperature, special
equipment, and the amount of
tongue weight the vehicle can carry
must be considered. See “Weight of
the Trailer Tongue” later in this
section for more information.
Maximum trailer weight is calculated
assuming only the driver is in the
tow vehicle and it has all the
required trailering equipment.
The weight of additional optional
equipment, passengers and cargo in
the tow vehicle must be subtracted
from the maximum trailer weight.

Black plate (1,1)GMC Acadia/Acadia Denali Owner Manual - 2012
Vehicle Care 10-1
Vehicle Care
General Information
General Information . . . . . . . . . . 10-2
California Proposition65 Warning . . . . . . . . . . . . . . . . . 10-3
California Perchlorate Materials Requirements . . . . 10-3
Accessories and Modifications . . . . . . . . . . . . . . . 10-3
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 10-4
Hood . . . . . . . . . . . . . . . . . . . . . . . . 10-4
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . 10-6
Engine Cover . . . . . . . . . . . . . . . . 10-8
Engine Oil . . . . . . . . . . . . . . . . . . . 10-8
Engine Oil Life System . . . . . 10-10
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . 10-12
Engine Air Cleaner/Filter . . . . 10-12 Cooling System . . . . . . . . . . . . 10-14
Engine Coolant . . . . . . . . . . . . . 10-14
Engine Overheating . . . . . . . . 10-18
Overheated Engine
Protection
Operating Mode . . . . . . . . . . . 10-20
Power Steering Fluid . . . . . . . 10-21
Washer Fluid . . . . . . . . . . . . . . . 10-22
Brakes . . . . . . . . . . . . . . . . . . . . . 10-22
Brake Fluid . . . . . . . . . . . . . . . . . 10-24
Battery . . . . . . . . . . . . . . . . . . . . . 10-25
All-Wheel Drive . . . . . . . . . . . . . 10-26
Starter Switch Check . . . . . . . 10-26
Automatic Transmission Shift Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . 10-26
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . 10-27
Park Brake and P (Park) Mechanism Check . . . . . . . . 10-27
Wiper Blade Replacement . . . . . . . . . . . . . . 10-28
Windshield Replacement . . . 10-28
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . 10-28
Bulb Replacement
Bulb Replacement . . . . . . . . . . 10-29
LED Lighting . . . . . . . . . . . . . . . 10-29
License Plate Lamp . . . . . . . . 10-29
Replacement Bulbs . . . . . . . . . 10-29
Electrical System
High Voltage Devices and Wiring . . . . . . . . . . . . . . . . . . . . . 10-30
Electrical System Overload . . . . . . . . . . . . . . . . . . 10-30
Fuses and Circuit Breakers . . . . . . . . . . . . . . . . . . 10-31
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . 10-31
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . . . . . 10-34

Black plate (7,1)GMC Acadia/Acadia Denali Owner Manual - 2012
Vehicle Care 10-7
A. Radiator Pressure Cap.See Cooling System on
page 10‑14.
B. Engine Coolant Recovery Cap. See Cooling System on
page 10‑14.
C. Remote Negative (−) Terminal. See Jump Starting on
page 10‑78.
D. Engine Compartment Fuse
Block on page 10‑31.
E. Remote Positive (+) Terminal. See Jump Starting on
page 10‑78. F. Power Steering Reservoir and
Cap (under engine cover).
See Power Steering Fluid on
page 10‑21.
G. Engine Oil Fill Cap. See “When
to Add Engine Oil” under
Engine Oil on page 10‑8.
H. Engine Cover on page 10‑8.
I. Engine Oil Dipstick (out of view). See “Checking Engine
Oil” under Engine Oil on
page 10‑8.
J. Automatic Transmission Fluid Dipstick. See “Checking the
Fluid Level” underAutomatic
Transmission Fluid on
page 10‑12. K. Brake Master Cylinder
Reservoir. See “Brake Fluid”
under Brakes on page 10‑22.
L. Engine Air Cleaner/Filter on
page 10‑12.
M. Windshield Washer Fluid Reservoir. See “Adding Washer
Fluid” under Washer Fluid on
page 10‑22.