weight GMC ENVOY 1999 User Guide

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4-45
Every vehicle is ready for some trailer towing. If yours
was built with trailering options, as many are, it's ready
for heavier trailers. But 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 2,000 lbs. (900 kg) or less. You should always
use a sway control if your trailer will weigh more
than 2,000 lbs. (900 kg). You can ask a hitch dealer
about sway controls.
Don't tow a trailer at all during the first 500 miles
(800 km) your new vehicle is driven. Your engine,
axle or other parts could be damaged.

Then, during the first 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.

You should use THIRD (3) (or, as you need to, a
lower gear) when towing a trailer. Operating your
vehicle in THIRD (3) when towing a trailer will
minimize heat buildup and extend the life of
your transmission.
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.
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4-46
Tow/Haul Mode
The Tow/Haul Mode is a feature that assists when
pulling a heavy trailer. The purpose of the Tow/Haul
Mode is:

Reduce the frequency of shifts when pulling a
heavy trailer.

Provide the same shift feel when pulling a heavy
trailer as when the vehicle is unloaded.

Reduce the need to change throttle positions when
pulling a heavy trailer.
This feature is turned on or off by pressing a button on
the shift lever. When the feature is on, a light on the
instrument panel will illuminate to indicate that the
Tow/Haul Mode has been selected. See ªTow/Haul
Mode Lightº in the Index. The Tow/Haul Mode is
automatically turned off each time the vehicle is started.
The Tow/Haul Mode is most effective when the vehicle
and trailer combined weight is at least 75% of the Gross
Vehicle Weight Rating (GVWR) and the maximum
trailer weight rating for the vehicle. See ªGross Vehicle
Weight Ratingº and ªTrailer Weightº in the Index.The Tow/Haul Mode for hauling a heavy trailer is most
useful under the following conditions:

When driving through hilly terrain at high speeds
below 55 mph (88 km/h).

When driving in low speed or stop and go traffic
below 55 mph (88 km/h).

When driving in parking lots.
Use the Tow/Haul Mode instead of the previous
recommendation to shift to THIRD (3) to improve fuel
economy at highway speeds and shift performance at
lower speeds. Operating in the Tow/Haul Mode when
not pulling a heavy trailer will not cause damage to the
vehicle, but you may experience reduced fuel economy
and undesirable performance from the engine and
transmission. The Tow/Haul Mode should be used only
when pulling a heavy trailer.
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4-47 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.
The trailer should never weigh more than
5,000 lbs. (2 268 kg). But even that can be too heavy.
Maximum trailer weight is calculated assuming the
driver and one passenger are 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. The weight of the trailer tongue also
affects maximum trailer weight. See ªWeight of the
Trailer Tongueº later in this section.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
1908 Colonel Sam Drive
Oshawa, Ontario L1H 8P7
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 ªLoading
Your Vehicleº in the Index for more information about
your vehicle's maximum load capacity.
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4-48
If you're using a weight-carrying hitch, the trailer
tongue (A) should weigh 10 percent of the total loaded
trailer weight (B). If you're using a weight
-distributing
hitch, the trailer tongue (A) should weigh 12 percent of
the total loaded trailer weight (B).
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 inflated to the upper limit for
cold tires. You'll find these numbers on the Certification/Tire
label on the driver's door edge, above the door latch, or see
ªTire Loadingº in the Index. Then be sure you don't go over
the GVW limit for your vehicle, including the weight of the
trailer tongue.
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 3,500 lbs. (1 589 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 (see ªCarbon Monoxideº in the
Index). Dirt and water can, too.
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4-50 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
RECIRCULATION because it only
recirculates the air inside your vehicle.
(See ªComfort 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.
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.
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9-4
Engine Compartment Fuse Block 6-57 . . . . . . . . . . . . . . . . . .
Engine Coolant 6-21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Oil 6-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adding 6-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additives 6-13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking 6-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Kind to Use 6-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pressure Gage 2-73 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Used 6-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
When to Change 6-13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exhaust, Engine 2-30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exit Lighting 2-43 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Express-Down Window 2-32 . . . . . . . . . . . . . . . . . . . . . . . . . .
Fabric Cleaning 6-46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filling a Portable Fuel Container 6-7 . . . . . . . . . . . . . . . . . . . .
Filling Your Tank 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filter
Air 6
-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote Oil 6-13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Finish Care 6-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Finish Damage 6-52 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
First Gear 2-20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flashers, Hazard Warning 5-2 . . . . . . . . . . . . . . . . . . . . . . . . .
Flash-To-Pass Feature 2-34 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flat Tire, Changing 5-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluids and Lubricants 7-45 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fog Lamp Switch 2-42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Foreign Countries, Fuel 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Four-Wheel Drive 2-22, 6-20 . . . . . . . . . . . . . . . . . . . . . . . . .
Four-Wheel Drive (Automatic Transfer Case) 2-22 . . . . . . . .
French Language Manual ii. . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Axle 6
-20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Front Reading Lamps 2
-43, 2-47 . . . . . . . . . . . . . . . . . . . . . . .
Front Storage Area 2-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Turn Signal Lamp Bulb Replacement 6-33 . . . . . . . . . .
Fuel 6-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filling a Portable Container 6-7 . . . . . . . . . . . . . . . . . . . . . .
Filling Your Tank 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Foreign Countries 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gage 2-75 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuse Block
Engine Compartment 6
-57 . . . . . . . . . . . . . . . . . . . . . . . . . .
Instrument Panel 6-55 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuses and Circuit Breakers 6-55 . . . . . . . . . . . . . . . . . . . . . . .
Gages
Engine Coolant Temperature 2-70 . . . . . . . . . . . . . . . . . . . .
Engine Oil Pressure 2-73 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel 2-75 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Voltmeter 2-68 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gas Cap 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gate Ajar Light 2-75 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GAWR 4-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gear Positions 2-18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Glove Box 2-46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GM Mobility Program for Persons with Disabilities 8-5 . . . . .
Gross Axle Weight Rating 4-41 . . . . . . . . . . . . . . . . . . . . . . . .
Gross Vehicle Weight Rating 4-41 . . . . . . . . . . . . . . . . . . . . . .
Guide en Fran†ais ii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GVWR 4
-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Halogen Bulbs 6-32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hazard Warning Flashers 5-2 . . . . . . . . . . . . . . . . . . . . . . . . . .
Head Restraints 1-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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9-9
Speech Impaired, Customer Assistance 8-4 . . . . . . . . . . . . . . .
Speedometer 2-65 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stains, Cleaning 6-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Starter Switch Check 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Starting Your Engine 2-16 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Steam 5-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Steering
In Emergencies 4
-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power 4-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Steering Wheel, Tilt 2-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage Compartments 2-46 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage, Vehicle 6-31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storing a Flat or Spare Tire and Tools 5-28 . . . . . . . . . . . . . . .
Stuck: In Sand, Mud, Ice or Snow 5-30 . . . . . . . . . . . . . . . . . .
Sun Visors 2-55 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sunglasses Storage 2-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sunroof 2-58 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symbols, Vehicle v. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tachometer 2-65 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Taillamp Bulb Replacement 6-34 . . . . . . . . . . . . . . . . . . . . . . .
Tape Player Care 3-25, 7-39 . . . . . . . . . . . . . . . . . . . . . . . . . .
Theft 2-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THEFTLOCK
3-21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thermostat 6-21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Third Gear 2-20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tilt Steering Wheel 2-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Time, Setting 3-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tire Chains 6-45 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tire Inflation Check 7-39 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tires
Alignment and Balance 6
-43 . . . . . . . . . . . . . . . . . . . . . . . .
Buying New 6-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Changing a Flat 5-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cleaning 6
-51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inflation 6-38, 7-39 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Rotation 6-39 . . . . . . . . . . . . . . . . . . . . . . . .
Pressure 6-38 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Temperature 6-43 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Traction 6-42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Treadwear 6-42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Uniform Quality Grading 6-42 . . . . . . . . . . . . . . . . . . . . . . .
Wear Indicators 6-40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
When It's Time for New 6-40 . . . . . . . . . . . . . . . . . . . . . . .
Top Strap 1-43 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Torque Lock 2-28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Torque, Wheel Nut 5-27, 6-60 . . . . . . . . . . . . . . . . . . . . . . . . .
Tow/Haul
Mode 4
-46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mode Light 2-75 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selector Switch 2-21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Towing a Trailer 4-44 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Towing, Recreational Vehicle 4-39 . . . . . . . . . . . . . . . . . . . . .
Towing Your Vehicle 5-7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Trailer
Brakes 4
-49 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driving on Grades 4-52 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driving with a Trailer 4-50 . . . . . . . . . . . . . . . . . . . . . . . . . .
Hitches 4-48 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance When Towing 4-54 . . . . . . . . . . . . . . . . . . . . .
Parking on Hills 4-52 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Chains 4-49 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tongue Weight 4-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Total Weight on Tires 4-48 . . . . . . . . . . . . . . . . . . . . . . . . . .
Towing 4-44 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Turn Signals 4-51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Weight 4-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wiring Harness 4-54 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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