trailer GMC ENVOY 2003 User Guide

4. Shift the transfer case to NEUTRAL (N). See
ªFour-Wheel Driveº in the Index for the proper
procedure to select the NEUTRAL position for your
vehicle.
5. Release the parking brake only after the vehicle
being towed is ®rmly attached to the towing
vehicle.
6. Turn the ignition off and remove the key. If the key
is not removed, the battery will drain.
{CAUTION:
Shifting a four-wheel-drive vehicle's transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in Park (P). You
or others could be injured. Make sure the
parking brake is ®rmly set before you shift the
transfer case to NEUTRAL.
Dolly Towing
Your vehicle was not designed to be dolly towed. If you
need to tow your vehicle, see ªDinghy Towingº earlier
in this section.
Loading Your Vehicle
The Certi®cation/Tire label is found on the driver's door
edge, above the door latch. The label shows the
size of your original tires and the in¯ation pressures
needed to obtain the gross weight capacity of your
vehicle. This is called the Gross Vehicle Weight Rating
(GVWR). The GVWR includes the weight of the
vehicle, all occupants, fuel, cargo and trailer tongue
weight, if pulling a trailer.
The Certi®cation/Tire label also tells you the maximum
weights for the front and rear axles, called Gross
Axle Weight Rating (GAWR).
4-47

Indicator Light
The indicator light on the in¯ator switch in the rear
passenger compartment also serves as an indicator for
internal system error. If the indicator light is ¯ashing
without the load leveling function or the in¯ator being
active, turn off the ignition. The next day turn on
the ignition and check the indicator light. The vehicle
can be driven with the light ¯ashing, but if it is you
should have the vehicle serviced as soon as possible.
Adding a Snow Plow or Similar
Equipment
Your vehicle was neither designed nor intended for a
snow plow.
Notice:Adding a snow plow or similar equipment
to your vehicle can damage it, and the repairs
wouldn't be covered by warranty. Do not install a
snow plow or similar equipment on your vehicle.
Towing a Trailer
{CAUTION:
If you don't use the correct equipment and
drive properly, you can lose control when you
pull a trailer. For example, if the trailer is too
heavy, the brakes may not work well -- or even
at all. You and your passengers could be
seriously injured. Pull a trailer only if you have
followed all the steps in this section. Ask your
dealer for advice and information about towing
a trailer with your vehicle.
Notice:Pulling a trailer improperly can damage
your vehicle and result in costly repairs not covered
by your warranty. To pull a trailer correctly, follow
the advice in this part, and see your dealer for
important information about towing a trailer with
your vehicle. Additional rear axle maintenance
is required for a vehicle used to tow a trailer. See
ªScheduled Maintenance Servicesº in the Index.
To identify the trailering capacity of your vehicle,
you should read the information in ªWeight of the Trailerº
that appears later in this section.
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Trailering is different than just driving your vehicle by
itself. Trailering means changes in handling, durability
and fuel economy. Successful, safe trailering takes
correct equipment, and it has to be used properly.
That's 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.
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 if your trailer will
weigh 4,000 lbs. (1 816 kg) or less. You should
always use a sway control if your trailer will weigh
more than 4,000 lbs. (1 816 kg). You can ask a
hitch dealer about sway controls.
·Don't tow a trailer at all during the ®rst 500 miles
(800 km) your new vehicle is driven. Your engine,
axle or other parts could be damaged.
·Then, during the ®rst 500 miles (800 km) that you
tow a trailer, don't drive over 50 mph (80 km/h)
and don't make starts at full throttle. This helps your
engine and other parts of your vehicle wear in at
the heavier loads.
·With an automatic transmission, 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.
Three important considerations have to do with weight:
·the weight of the trailer,
·the weight of the trailer tongue
·and the weight on your vehicle's tires.
4-51

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. And, it can also depend on any special equipment that
you have on your vehicle.
Look in the following chart to ®nd the maximum trailer weight for your vehicle.
Vehicle Axle Ratio Max.Trailer Wt. *GCWR
2WD Envoy (L6 Engine)3.42 5,300 lbs (2 406 kg) 10,000 lbs. (4 535 kg)
3.73 5,800 lbs. (2 633 kg) 10,500 lbs (4 762 kg)
4.10 6,300 lbs. (2 860 kg) 11,000 lbs. (4 989 kg)
4WD Envoy (L6 Engine)3.42 5,200 lbs. (2 361 kg) 10,000 lbs. (4 535 kg)
3.73 5,700 lbs. (2 588 kg) 10,500 lbs. (4 762 kg)
4.10 6,200 lbs. (2 815 kg) 11,000 lbs. (4 989 kg)
2WD Envoy XL (L6 Engine)3.42 4,900 lbs. (2 225 kg) 10,000 lbs. (4 535 kg)
3.73 5,400 lbs. (2 452 kg) 10,500 lbs. (4 762 kg)
4.10 5,900 lbs. (2 679 kg) 11,000 lbs. (4 989 kg)
4WD Envoy XL (L6 Engine)3.42 4,800 lbs. (2 179 kg) 10,000 lbs. (4 535 kg)
3.73 5,300 lbs. (2 406 kg) 10,500 lbs. (4 762 kg)
4.10 5,800 lbs. (2 633 kg) 11,000 lbs. (4 989 kg)
4-52

Vehicle Axle Ratio Max.Trailer Wt. *GCWR
2WD Envoy XL (V8 Engine)3.42 5,800 lbs. (2 633 kg) 11,000 lbs. (4 994 kg)
3.73 7,200 lbs. (3 269 kg) 12,500 lbs. (5 675 kg)
4WD Envoy XL (V8 Engine)3.42 5,700 lbs. (2 588 kg) 11,000 lbs. (4 994 kg)
3.73 7,000 lbs. (3 178 kg) 12,500 lbs. (5 675 kg)
*The Gross Combination Weight Rating (GCWR) is the total
allowable weight of the completely loaded vehicle and trailer
including any passengers, cargo, equipment and conversion.
The GCWR for your vehicle should not be exceeded.
You can ask your dealer for our trailering information or
advice, or you can write us at the address listed in
your Warranty and Owner Assistance Information
Booklet.In Canada, write to:
General Motors of Canada Limited
Customer Communication Centre, 163-005
1908 Colonel Sam Drive
Oshawa, Ontario L1H 8P7
4-53

Weight of the Trailer Tongue
The tongue load (A) of any trailer is an important weight
to measure because it affects the total or gross weight
of your vehicle. The Gross Vehicle Weight (GVW)
includes the curb weight of the vehicle, any cargo you
may carry in it, and the people who will be riding in
the vehicle. And if you will tow a trailer, you must add
the tongue load to the GVW because your vehicle will be
carrying that weight, too. See
Loading Your Vehicle
on page 4-47for more information about your vehicle's
maximum load capacity.If you're using a weight-carrying or a weight-distributing
hitch, the trailer tongue weight (A) should be 10 percent
to 15 percent of the total loaded trailer weight (B).
Do not exceed the maximum allowable tongue weight
for your vehicle.
After you've loaded your trailer, weigh the trailer and
then the tongue, separately, to see if the weights
are proper. If they aren't, you may be able to get them
right simply by moving some items around in the
trailer.
Total Weight on Your Vehicle's Tires
Be sure your vehicle's tires are in¯ated to the upper limit
for cold tires. You'll ®nd these numbers on the
Certi®cation label at the rear edge of the driver's door.
Then be sure you don't go over the GVW limit for
your vehicle, including the weight of the trailer tongue.
4-54

Hitches
It's important to have the correct hitch equipment.
Crosswinds, large trucks going by and rough roads are
a few reasons why you'll need the right hitch. Here
are some rules to follow:
·If you'll be pulling a trailer that, when loaded, will
weigh more than 4,000 lbs. (1 816 kg), be sure to
use a properly mounted, weight-distributing
hitch and sway control of the proper size. This
equipment is very important for proper vehicle
loading and good handling when you're driving.
·Will you have to make any holes in the body of
your vehicle when you install a trailer hitch?
If you do, then be sure to seal the holes later when
you remove the hitch. If you don't seal them,
deadly carbon monoxide (CO) from your exhaust
can get into your vehicle. Dirt and water can, too.
Safety Chains
You should always attach chains between your vehicle
and your trailer. Cross the safety chains under the
tongue of the trailer to help prevent the tongue from
contacting the road if it becomes separated from
the hitch.
Instructions about safety chains may be provided by the
hitch manufacturer or by the trailer manufacturer.Follow the manufacturer's recommendation for attaching
safety chains and do not attach them to the bumper.
Always leave just enough slack so you can turn
with your rig. Never allow safety chains to drag on the
ground.
Trailer Brakes
If your trailer weighs more than 1,500 lbs. (680 kg)
loaded, then it needs its own brakes Ð and they must
be adequate. Be sure to read and follow the instructions
for the trailer brakes so you'll be able to install, adjust
and maintain them properly.
Your trailer's brake system can tap into the vehicle's
hydraulic brake system only if:
·The trailer parts can withstand 3,000 psi
(20 650 kPa) of pressure.
·The trailer's brake system will use less than
0.02 cubic inch (0.3 cc) of ¯uid from your vehicle's
master cylinder. Otherwise, both braking systems
won't work well. You could even lose your brakes.
If everything checks out this far, then make the brake
¯uid tap at the port on the master cylinder that
sends ¯uid to the rear brakes. But don't use copper
tubing for this. If you do, it will bend and ®nally break off.
Use steel brake tubing.
4-55

Driving with a Trailer
{CAUTION:
If you have a rear-most window open and you
pull a trailer with your vehicle, carbon
monoxide (CO) could come into your vehicle.
You can't see or smell CO. It can cause
unconsciousness or death. See ªEngine
Exhaustº in the Index. To maximize your safety
when towing a trailer:
·Have your exhaust system inspected for
leaks, and make necessary repairs before
starting on your trip.
·Keep the rear-most windows closed.
·If exhaust does come into your vehicle
through a window in the rear or another
opening, drive with your front, main heating
or cooling system on and with the fan on
any speed. This will bring fresh, outside air
into your vehicle. Do not use the climate
control setting for maximum air because it
only recirculates the air inside your vehicle.
See ªClimate Controlsº in the Index.Towing a trailer requires a certain amount of experience.
Before setting out for the open road, you'll want to get
to know your rig. Acquaint yourself 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 a good deal longer and not nearly as
responsive as your vehicle is by itself.
Before you start, check the trailer hitch and platform
(and attachments), safety chains, electrical connector,
lamps, tires and mirror adjustment. If the trailer has
electric brakes, start your vehicle and trailer moving and
then apply the trailer brake controller by hand to be
sure the brakes are working. This lets you check your
electrical connection at the same time.
During your trip, check occasionally to be sure that the
load is secure, and that the lamps and any trailer
brakes are still working.
4-56

Following Distance
Stay at least twice as far behind the vehicle ahead as
you would when driving your vehicle without a trailer.
This can help you avoid situations that require
heavy braking and sudden turns.
Passing
You'll need more passing distance up ahead when
you're towing a trailer. And, because you're a good deal
longer, you'll need to go much farther beyond the
passed vehicle before you can return to your lane.
Backing Up
Hold the bottom of the steering wheel with one hand.
Then, to move the trailer to the left, just 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. Your vehicle could be damaged. Avoid
making very sharp turns while trailering.
When you're turning with a trailer, make wider turns
than normal. Do this so your trailer won't 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 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's
important to check occasionally to be sure the trailer
bulbs are still working.
4-57

Driving On Grades
Reduce speed and shift to a lower gearbeforeyou start
down a long or steep downgrade. If you don't shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
You can tow in DRIVE (D). You may want to shift the
transmission to THIRD (3) or a lower gear, under heavy
loads 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 you turn your
engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a
few minutes before turning the engine off. If you do get
the overheat warning, see
Engine Overheating on
page 5-27.
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's
how to do it:
1. Apply your regular brakes, but don't shift into
PARK (P) yet. When parking uphill, turn your wheels
away from the curb. When parking downhill, turn
your wheels into the curb.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel 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 then shift into PARK (P).
5. Release the regular brakes.
4-58