towing GMC ENVOY 2009 Owner's Guide

Rear Towing (Rear Wheels Off the
Ground)Two-Wheel-Drive Vehicles
Use the following procedure to dolly tow a
two-wheel-drive vehicle from the rear:
1. Attach the dolly to the tow vehicle following the
dolly manufacturer’s instructions.
2. Drive the rear wheels onto the dolly.
3. Firmly set the parking brake. SeeParking Brake on
page 2-33.
4. Put the transmission in P (Park).
5. Secure the vehicle to the dolly following the
manufacturer’s instructions.
6. Use an adequate clamping device designed for
towing to ensure that the front wheels are locked
into the straight position.
7. Turn the ignition to LOCK/OFF.
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Four-Wheel-Drive Vehicles
Use the following procedure to dolly tow a
four-wheel-drive vehicle from the rear:
1. Attach the dolly to the tow vehicle following the
dolly manufacturer’s instructions.
2. Drive the rear wheels onto the dolly.
3. Firmly set the parking brake. SeeParking Brake on
page 2-33.
4. Put the transmission in P (Park).
5. Secure the vehicle to the dolly following the
manufacturer’s instructions.
6. Use an adequate clamping device designed for
towing to ensure that the front wheels are locked
into the straight position.{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer case
into N (Neutral) can cause the vehicle to roll even
if the transmission is in P (Park). The driver or
others could be injured. Make sure the parking
brake is rmly set before the transfer case is
shifted to N (Neutral).
7. Shift the transfer case to Neutral. See “Shifting into
Neutral” underFour-Wheel Drive on page 2-28.
8. Turn the ignition to LOCK/OFF.
After towing, see “Shifting Out of Neutral” under
Four-Wheel Drive on page 2-28.
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Towing a Trailer
{CAUTION:
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 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.Notice:Pulling a trailer improperly can damage the
vehicle and result in costly repairs not covered
by the vehicle warranty. To pull a trailer correctly,
follow the advice in this section and see your
dealer/retailer for important information about
towing a trailer with the vehicle.
To identify the trailering capacity of the vehicle, read
the information in “Weight of the Trailer” that appears
later in this section.
Trailering is different than just driving the vehicle by itself.
Trailering means changes in handling, acceleration,
braking, durability and fuel economy. Successful, safe
trailering takes correct equipment, and it has to be used
properly.
The following information has 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 pulling a
trailer.
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Weight of the Trailer Tongue
The tongue load (A) of any trailer is an important weight
to measure because it affects the total gross weight
of the vehicle. The Gross Vehicle Weight (GVW)
includes the curb weight of the vehicle, any cargo
carried in it, and the people who will be riding in the
vehicle. If there are a lot of options, equipment,
passengers or cargo in the vehicle, it will reduce the
tongue weight the vehicle can carry, which will also
reduce the trailer weight the vehicle can tow. If towing a
trailer, the tongue load must be added to the GVW
because the vehicle will be carrying that weight, too. See
Loading the Vehicle on page 4-31for more information
about the vehicle’s maximum load capacity.The trailer tongue weight (A) should be 10 percent
to 15 percent of the total loaded trailer weight, up to a
maximum or 400 lbs (181 kg) with a weight carrying hitch.
The trailer tongue weight (A) should be 10 percent to
15 percent of the total loaded trailer weight, up to a
maximum of 900 lbs (408 kg) with a weight distributing
hitch.
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Driving with a Trailer
{CAUTION:
When towing a trailer, exhaust gases may collect
at the rear of the vehicle and enter if the liftgate,
trunk/hatch, or rear-most window is open.
Engine exhaust contains carbon monoxide (CO)
which cannot be seen or smelled. It can cause
unconsciousness and even death.
To maximize safety when towing a trailer:
Have the exhaust system inspected for leaks
and make necessary repairs before starting
a trip.
Never drive with the liftgate, trunk/hatch, or
rear-most window open.
Fully open the air outlets on or under the
instrument panel.
Adjust the Climate Control system to a setting
that brings in only outside air and set the fan
speed to the highest setting. See Climate
Control System in the Index.
For more information about carbon monoxide, see
Engine Exhaust on page 2-37.Towing a trailer requires a certain amount of experience.
Get to know the rig before setting out for the open road.
Get acquainted with the feel of handling and braking with
the added weight of the trailer. And always keep in mind
that the vehicle you are driving is now longer and not as
responsive as the vehicle is by itself.
Before starting, 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. This checks the electrical connection
at the same time.
During the trip, check occasionally to be sure that the
load is secure, and that the lamps and any trailer brakes
are still working.
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 much
farther beyond the passed vehicle before returning to
the lane.
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Backing Up
Hold the bottom of the steering wheel with one hand.
Then, 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.
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. Do this so the trailer will not strike soft shoulders,
curbs, road signs, trees or other objects. Avoid jerky or
sudden maneuvers. Signal well in advance.
Turn Signals When Towing a Trailer
The arrows on the instrument panel ash whenever
signaling a turn or lane change. Properly hooked up, the
trailer lamps also ash, telling other drivers the vehicle
is turning, changing lanes or stopping.When towing a trailer, the arrows on the instrument
panel ash for turns even if the bulbs on the trailer are
burned out. For this reason you may think other
drivers are seeing the signal when they are not. It is
important to check occasionally to be sure the
trailer bulbs are still working.
Driving On Grades
Reduce speed and shift to a lower gearbeforestarting
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.
Vehicles can tow in D (Drive). Shift the transmission to
a lower gear if the transmission shifts too often under
heavy loads and/or hilly conditions.
When towing at high altitude on steep uphill grades,
consider the following: 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, seeEngine Overheating on page 5-30.
4-54

Leaving After Parking on a Hill
1. Apply and hold the brake pedal while you:
start the 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
The vehicle needs service more often when pulling a
trailer. See this manual’s Maintenance Schedule
or Index for more information. Things that are especially
important in trailer operation are automatic transmission
uid, engine oil, axle lubricant, belts, cooling system
and brake system. It is a good idea to inspect
these before and during the trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Trailer Wiring Harness
The vehicle may have a seven-wire trailer towing
harness. This harness may have a seven-pin universal
heavy-duty trailer connector (if equipped with the
trailering package) that is attached to a bracket on
the hitch platform or included with the four-pin trailer
towing harness. If the vehicle is not equipped with the
heavy-duty trailer connector, one may be purchased from
your dealer/retailer.
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The seven-wire harness contains the following trailer
circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Running Lamps
White: Ground
Light Green: Back-up Lamps
Red: Battery Feed
Dark Blue: Electric BrakesIf towing a light-duty trailer with a standard four-way
round pin connector, an adapter connector is available
from your dealer/retailer.
If charging a remote (non-vehicle) battery, turn on the
headlamps to boost the vehicle system voltage and
properly charge the battery.
The vehicle is also equipped with wiring for an
electric trailer brake controller. These wires are
located inside the vehicle on the driver side under the
instrument panel. These wires should be connected
to an electric trailer brake controller by your
dealer/retailer or a qualied service center.
4-57

If No Steam Is Coming From The
Engine Compartment
If an engine overheat warning is displayed but no steam
can be seen or heard, the problem may not be too
serious. Sometimes the engine can get a little too hot
when the vehicle:
Climbs a long hill on a hot day.
Stops after high-speed driving.
Idles for long periods in traffic.
Tows a trailer.
If the overheat warning is displayed with no sign of steam:
1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and
to the highest fan speed. Open the windows as
necessary.
3. In heavy traffic, let the engine idle in N (Neutral)
while stopped. If it is safe to do so, pull off the
road, shift to P (Park) or N (Neutral) and let
the engine idle.
If the temperature overheat gage is no longer in the
overheat zone or an overheat warning no longer
displays, the vehicle can be driven. Continue to drivethe vehicle slow for about 10 minutes. Keep a safe
vehicle distance from the car in front of you. If the
warning does not come back on, continue to drive
normally.
If the warning continues, pull over, stop, and park the
vehicle right away.
If there is no sign of steam, idle the engine for three
minutes while parked. If the warning is still displayed,
turn off the engine until it cools down.Engine Fan Noise
The vehicle has a clutched engine cooling fan. When the
clutch is engaged, the fan spins faster to provide more air
to cool the engine. In most everyday driving conditions
the clutch is not engaged. This improves fuel economy
and reduces fan noise. Under heavy vehicle loading,
trailer towing, and/or high outside temperatures, the fan
speed increases when the clutch engages so you may
hear an increase in fan noise. This is normal and should
not be mistaken as the transmission slipping or making
extra shifts. It is merely the cooling system functioning
properly. The fan will slow down when additional cooling
is not required and the clutch disengages.
You may also hear this fan noise when the engine is
started. The sound will go away as the fan clutch
disengages.
5-32

(e)Make sure the safety belt reminder light and safety
belt assemblies are working properly. Look for any other
loose or damaged safety belt system parts. If you see
anything that might keep a safety belt system from doing
its job, have it repaired. Have any torn or frayed safety
belts replaced. Also see Checking the Restraint Systems
on page 1-70.
(f)Lubricate all key lock cylinders, hood latch assembly,
secondary latch, pivots, spring anchor, release pawl,
rear compartment hinges, outer liftgate handle pivot
points, rear door detent link, roller mechanism, liftgate
handle pivot points, latch bolt, fuel door hinge, cargo
door hinge, locks, and folding seat hardware. More
frequent lubrication may be required when exposed
to a corrosive environment. Applying silicone grease
on weatherstrips with a clean cloth will make them last
longer, seal better, and not stick or squeak.
(g)Inspect hoses for cracks, chafing, leaks, kinks, and
proper installation.
(h)Change automatic transmission fluid and filter if the
vehicle is mainly driven under one or more of these
conditions:
In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police, or delivery
service.(i)Drain, flush, and refill cooling system. This service can
be complex; you should have your dealer/retailer perform
this service. See Engine Coolant on page 5-25 for what to
use. Inspect hoses. Clean radiator, condenser, pressure
cap, and filler neck. Pressure test the cooling system and
pressure cap.
(j)A fluid loss in any vehicle system could indicate a
problem. Have the system inspected and repaired and
the fluid level checked. Add fluid if needed.
(k)If driving regularly under dusty conditions, inspect
the filter at each engine oil change.
(l)Visually inspect belt for fraying, excessive cracks, or
obvious damage. Replace belt if necessary.
Owner Checks and Services
These owner checks and services should be performed
at the intervals specied to help ensure vehicle safety,
dependability, and emission control performance. Your
dealer/retailer can assist with these checks and services.
Be sure any necessary repairs are completed at once.
Whenever any uids or lubricants are added to the
vehicle, make sure they are the proper ones, as shown
inRecommended Fluids and Lubricants on page 6-12.
6-8