transmission GMC ACADIA 2008 Owner's Guide

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 you start your vehicle. It will activate and the
StabiliTrak
®light will ash if it senses that any of the
wheels are spinning or beginning to lose traction while
driving. If you turn off traction control, 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 you allow the wheel(s) of one axle to spin
excessively while the StabiliTrak
®, ABS and brake
warning lights and the SERVICE STABILITRAK
message are displayed, you could damage the
transfer case. The repairs would not be covered by
your warranty. Reduce engine power and do not
spin the wheel(s) excessively while these lights and
this message 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, you may
notice a reduction in acceleration, or may hear a noise
or vibration. This is normal.
If your vehicle is in cruise control when the system
activates, the StabiliTrak
®light will ash and the cruise
control will automatically disengage. When road
conditions allow you to use cruise again, you may
re-engage the cruise control. SeeCruise Control on
page 3-12.
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, you should see your dealer/retailer for service.
4-8

Hill and Mountain Roads
Driving on steep hills or through mountains is different
than driving on at or rolling terrain. Tips for driving
in these conditions include:
Keep your vehicle serviced and in good shape.
Check all uid levels and brakes, tires, cooling
system, and transmission.
Going down steep or long hills, shift to a lower gear.
{CAUTION:
If you do not shift down, the brakes could get
so hot that they would not work well. You
would then have poor braking or even none
going down a hill. You could crash. Shift down
to let the engine assist the brakes on a steep
downhill slope.
{CAUTION:
Coasting downhill in NEUTRAL (N) or with the
ignition off is dangerous. The brakes will have
to do all the work of slowing down and they
could get so hot that they would not work well.
You would then have poor braking or even
none going down a hill. You could crash.
Always have the engine running and your
vehicle in gear when you go downhill.
Stay in your own lane. Do not swing wide or cut
across the center of the road. Drive at speeds
that let you stay in your own lane.
Top of hills: Be alert — something could be in your
lane (stalled car, accident).
Pay attention to special road signs (falling rocks
area, winding roads, long grades, passing or
no-passing zones) and take appropriate action.
4-16

Rocking Your Vehicle to Get It Out
First, turn the steering wheel left and right to clear
the area around the front wheels. Turn the traction
control part of the StabiliTrak
®System off. See
StabiliTrak®System on page 4-6. Then shift back and
forth between REVERSE (R) and a forward gear,
spinning the wheels as little as possible. To prevent
transmission wear, wait until the wheels stop spinning
before shifting gears. Release the accelerator pedal
while you shift, and press lightly on the accelerator pedal
when the transmission is in gear. By slowly spinning
the wheels in the forward and reverse directions, you will
cause a rocking motion that could free your vehicle. If
that does not get your vehicle out after a few tries,
it might need to be towed out. If your vehicle does need
to be towed out, seeTowing Your Vehicle on
page 4-26.
Loading Your Vehicle
It is very important to know how much weight your
vehicle can carry. This weight is called the
vehicle capacity weight and includes the weight of
all occupants, cargo, and all nonfactory-installed
options. Two labels on your vehicle show how
much weight it may properly carry, the Tire and
Loading Information label and the Certication/Tire
label.
{CAUTION:
Do not load your vehicle any heavier than
the Gross Vehicle Weight Rating (GVWR),
or either the maximum front or rear Gross
Axle Weight Rating (GAWR). If you do,
parts on your vehicle can break, and it
can change the way your vehicle handles.
These could cause you to lose control
and crash. Also, overloading can shorten
the life of your vehicle.
4-21

Here are some important things to consider before you
do recreational vehicle towing:
What’s the towing capacity of the towing vehicle?
Be sure you read the tow vehicle manufacturer’s
recommendations.
How far will you tow? Some vehicles have
restrictions on how far and how long they can tow.
Do you have the proper towing equipment?
See your dealer/retailer or trailering professional for
additional advice and equipment recommendations.
Is your vehicle ready to be towed? Just as you
would prepare your vehicle for a long trip, you’ll
want to make sure your vehicle is prepared to be
towed. SeeBefore Leaving on a Long Trip on
page 4-15.
Dinghy Towing
If you have a front-wheel-drive vehicle, it can be dinghy
towed from the front. These vehicles may also be
towed by putting the front wheels on a dolly. See “Dolly
Towing” later in this section.
If you have an all-wheel-drive vehicle, it can be dinghy
towed from the front. You can also tow these vehicles
by placing them on a platform trailer with all four wheels
off of the ground. These vehicles cannot be towed
using a dolly.
For vehicles being dinghy towed, the vehicle should be
run at the beginning of each day and at each RV
fuel stop for about ve minutes. This will ensure proper
lubrication of transmission components. Re-connect
the vehicle’s battery to start the vehicle.
4-27

To tow your vehicle from the front with all four wheels
on the ground:
1. Position the vehicle to tow and then secure it.
2. Turn the ignition to LOCK/OFF.
3. Set the parking brake.
4. Turn the ignition to ACC/ACCESSORY.
5. Shift your transmission to NEUTRAL (N).
6. To prevent your battery from draining while the
vehicle is being towed, disconnect the vehicle’s
battery. Contact your dealer/retailer for more
information on the battery disconnection procedure.
7. Release the parking brake.Notice:If you tow your vehicle without performing
each of the steps listed under “Dinghy Towing,”
you could damage the automatic transmission. Be
sure to follow all steps of the dinghy towing
procedure prior to and after towing your vehicle.
Notice:If you exceed 65 mph (105 km/h) while
towing your vehicle, it could be damaged. Never
exceed 65 mph (105 km/h) while towing your vehicle.
Once you have reached your destination:
1. Set the parking brake.
2. Re-connect the vehicle’s battery. Contact your
dealer/retailer for more information on the battery
connection procedure.
3. Turn the ignition key to LOCK/OFF and remove the
key from the ignition.
Notice:Don’t tow a vehicle with the front drive
wheels on the ground if one of the front tires is a
compact spare tire. Towing with two different
tire sizes on the front of the vehicle can cause
severe damage to the transmission.
4-28

That is the reason for this part. In it are many
time-tested, important trailering tips and safety rules.
Many of these are important for your safety and that of
your passengers. So please read this section carefully
before you pull a trailer.
Load-pulling components such as the engine,
transmission, rear axle, wheel assemblies and tires are
forced to work harder against the drag of the added
weight. The engine is required to operate at relatively
higher speeds and under greater loads, generating extra
heat. What’s more, the trailer adds considerably to
wind resistance, increasing the pulling requirements.
If You Do Decide to Pull a Trailer
If you do, here are some important points:
There are many different laws, including speed limit
restrictions, having to do with trailering. Make sure
your rig will be legal, not only where you live
but also where you’ll be driving. A good source for
this information can be state or provincial police.
Consider using a sway control. You can ask a hitch
dealer/retailer about sway controls.
Do not tow a trailer at all during the rst 500 miles
(805 km) your new vehicle is driven. Your engine,
axle or other parts could be damaged.
Then, during the rst 500 miles (805 km) that you
tow a trailer, do not drive over 50 mph (80 km/h)
and do not make starts at full throttle. This
helps your engine and other parts of your vehicle
wear in at the heavier loads.
Obey speed limit restrictions when towing a trailer.
Do not drive faster than the maximum posted
speed for trailers, or no more than 55 mph
(90 km/h), to save wear on your vehicle’s parts.
You can tow in DRIVE (D). You may want to shift
the transmission to THIRD (3) or, if necessary, a
lower gear selection if the transmission shifts
too often (e.g., under heavy loads and/or hilly
conditions). See “Tow/Haul Mode” later in
this section.
Three important considerations have to do with weight:
The weight of the trailer
The weight of the trailer tongue
And the total weight on your vehicle’s tires
4-31

Tow/Haul Mode
Tow/Haul is a feature that assists when pulling a heavy
trailer or a large or heavy load. The purpose of the
Tow/Haul mode is to:
Reduce the frequency and improve the predictability
of transmission shifts when pulling a heavy trailer or
a large or heavy load.
Provide the same solid shift feel when pulling a
heavy trailer or a large or heavy load as when
the vehicle is unloaded.
Improve control of vehicle speed while requiring
less throttle pedal activity when pulling a heavy
trailer or a large or heavy load.
Increase the charging system voltage to assist in
recharging a battery installed in a trailer.Press this button on the
console to enable/disable
the tow/haul mode.
A light on the instrument
panel will come 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.
4-32

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 Weight of the Trailer later in this section. Tow/Haul is
most useful under the following driving conditions:
When pulling a heavy trailer or a large or heavy load
through rolling terrain.
When pulling a heavy trailer or a large or heavy load
in stop and go traffic.
When pulling a heavy trailer or a large or heavy load
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 at all will not cause damage. However,
there is no benet to the selection of Tow/Haul when the
vehicle is unloaded. Such a selection when unloaded
may result in unpleasant engine and transmission driving
characteristics and reduced fuel economy. Tow/Haul
is recommended only when pulling a heavy trailer or a
large or heavy load.
Weight of the Trailer
How heavy can a trailer safely be?
It depends on how you plan to use your rig. For
example, speed, altitude, road grades, outside
temperature and how much your vehicle is used to pull
a trailer are all important. It can also depend on any
special equipment that you have on your vehicle,
and the amount of tongue weight the vehicle can carry.
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.
4-33

Turn Signals When Towing a Trailer
When you tow a trailer, your vehicle may need a
different turn signal asher and/or extra wiring. Check
with your dealer/retailer. The arrows on your instrument
panel will ash whenever you signal a turn or lane
change. Properly hooked up, the trailer lamps will also
ash, telling other drivers you’re about to turn,
change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will ash for turns even if the bulbs on the trailer
are burned out. Thus, you may think drivers behind
you are seeing your signal when they are not. It
is important to check occasionally to be sure the trailer
bulbs are still working.
Driving on Grades
Your vehicle is designed primarily as a passenger and
load carrying vehicle. If you tow a trailer, your vehicle
will require more frequent maintenance due to the
additional load. Because of the added load of the trailer,
your vehicle’s engine may overheat on hot days,
when going up a long or steep grade with a trailer. If the
engine coolant temperature gage indicates overheating,
turn off the air conditioning to reduce engine load,
pull off the road and stop in a safe spot.
Reduce speed and shift to a lower gear before you start
down a long or steep downgrade. If you do not shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
On a long uphill grade, shift down and reduce your
speed to around 55 mph (88 km/h) to reduce the
possibility of the engine and the transmission
overheating.
4-39

Parking on Hills
{CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here is
how to do it:
1. Apply your regular brakes, but do not shift into
PARK (P).
When parking uphill, turn your wheels away from
the curb. When parking downhill, turn your wheels
into the curb.
2. Have someone place chocks behind the trailer
wheels.
3. When the chocks are in place, release the regular
brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake and shift into PARK (P).
5. Release the regular brakes.
When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
start your engine,
shift into a gear, and
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
Your vehicle will need service more often when you are
pulling a trailer. SeeScheduled Maintenance on
page 6-4for more information. Things that are especially
important in trailer operation are automatic transmission
uid (do not overll), engine oil, axle lubricant, drive
belt, cooling system and brake system. Each of these is
covered in this manual, and the Index will help you
nd them quickly. If you are trailering, it is a good idea
to review this information before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
4-40