2001 GMC ENVOY Owners Manual

4-41
CAUTION:
Snow can trap exhaust gases under your vehicle.
This can cause deadly CO (carbon monoxide) gas
to get inside. CO could overcome you and kill
you. You can't see it or smell it, so you might not
know it is in your vehicle. Clear away snow from
around the base of your vehicle, especially any
that is blocking your exhaust pipe. And check
around again from time to time to be sure snow
doesn't collect there.
Open a window just a little on the side of the
vehicle that's away from the wind. This will
help keep CO out.
Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little faster
than just idle. That is, push the accelerator slightly. This
uses less fuel for the heat that you get and it keeps the
battery charged. You will need a well
-charged battery to
restart the vehicle, and possibly for signaling later on
with your headlamps. Let the heater run for a while.Then, shut the engine off and close the window almost
all the way to preserve the heat. Start the engine again
and repeat this only when you feel really uncomfortable
from the cold. But do it as little as possible. Preserve the
fuel as long as you can. To help keep warm, you can get
out of the vehicle and do some fairly vigorous exercises
every half hour or so until help comes.
Recreational Vehicle Towing
There may be times when you want to tow your vehicle
behind another vehicle for use at your destination.
Be sure to use the proper towing equipment designed
for recreational vehicle towing. Follow the instructions
for the towing equipment.
When towing your vehicle, turn the ignition to OFF.
To prevent your battery from draining while towing,
remove the RDO BATT and CLSTR fuses from the
instrument panel fuse block. Be sure to replace the fuses
when you reach your destination. See ªFuses and Circuit
Breakersº in the Index.
ProCarManuals.com

4-42 Two-Wheel Drive Vehicles and Vehicles
with the Electronic Shift Transfer Case
Tw o-wheel-drive vehicles and vehicles with the
Electronic Shift Transfer Case should not be towed
with all four wheels on the ground. These transmissions
have no provisions for internal lubrication while being
towed. To properly tow these vehicles, they should be
placed on a platform trailer with all four wheels off the
ground. Towing with all four wheels on the ground
should be avoided.
In rare cases when it's unavoidable and your vehicle
has to be towed with all four wheels on the ground,
the propeller shaft to axle yoke orientation should be
marked and the propeller shaft removed following
the applicable service manual removal/installation
procedure. See ªService and Owner Publicationsº in
the Index.
Dust or dirt can enter the back of the transmission
through the opening created by removing the propeller
shaft if proper protection is not provided. Also, check
the transmission fluid level before driving the vehicle.
Four-Wheel-Drive Vehicles
(Automatic Transfer Case)
Use the following procedure to correctly tow your
vehicle on all four wheels:
1. Firmly set the parking brake.
2. Place the transmission in PARK (P).
3. Securely attach the vehicle being towed to the
tow vehicle.
ProCarManuals.com

4-43
4. With the engine running, shift the transfer case to
NEUTRAL. See ªFour
-Wheel Driveº in the Index
for the proper procedure to select the NEUTRAL
position for your vehicle.
CAUTION:
Shifting the transfer case into NEUTRAL can
cause your vehicle to roll even if the transmission
is in PARK (P), for an automatic transmission,
or if your vehicle is in gear, for a manual
transmission. You or others could be injured.
Make sure the parking brake is firmly set
before you shift the transfer case into NEUTRAL.
See ªFour
-Wheel Drive (Automatic Transfer Case)º
in the Index.
5. Release the parking brake only after the vehicle
being towed is firmly attached to the towing vehicle.
6. Turn the ignition to OFF. The OFF position unlocks
the steering column and reduces battery drain.
Unlocking the steering column will allow the proper
movement of the front wheels and tires during towing.
Loading Your Vehicle
The Certification/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 inflation 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 Certification/Tire label also tells you the maximum
weights for the front and rear axles, called Gross Axle
Weight Rating (GAWR).
ProCarManuals.com

4-44
To find out the actual loads on your front and rear axles,
you need to go to a weigh station and weigh your vehicle.
Your dealer can help you with this. Be sure to spread out
your load equally on both sides of the centerline.
Never exceed the GVWR for your vehicle, or the GAWR
for either the front or rear axle.
If you do have a heavy load, you should spread it out.
Similar appearing vehicles may have different GVWRs
and payloads. Please note your vehicle's Certification/Tire
label or consult your dealer for additional details.
CAUTION:
Do not load your vehicle any heavier than the
GVWR, or either the maximum front or rear
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.
Using heavier suspension components to get added
durability might not change your weight ratings.
Ask your dealer to help you load your vehicle the
right way.
NOTICE:
Your warranty does not cover parts or
components that fail because of overloading.
If you put things inside your vehicle -- like suitcases,
tools, packages, or anything else
-- they will go as fast
as the vehicle goes. If you have to stop or turn quickly,
or if there is a crash, they'll keep going.
ProCarManuals.com

4-45
CAUTION:
Things you put inside your vehicle can strike
and injure people in a sudden stop or turn,
or in a crash.

Put things in the cargo area of your vehicle.
Try to spread the weight evenly.

Never stack heavier things, like suitcases,
inside the vehicle so that some of them are
above the tops of the seats.

Don't leave an unsecured child restraint
in your vehicle.

When you carry something inside the
vehicle, secure it whenever you can.

Don't leave a seat folded down unless
you need to.
There's also important loading information for off-road
driving in this manual. See ªLoading Your Vehicle for
Off
-Road Drivingº in the Index.
Payload
The payload capacity is shown on the Certification/Tire
label. This is the maximum load capacity that your
vehicle can carry. Be sure to include the weight of the
occupants as part of your load. If you added any
accessories or equipment after your vehicle left the
factory, remember to subtract the weight of these things
from the payload. Your dealer can help you with this.
Electronic Level Control (If Equipped)
If your vehicle is equipped with the electronic level
control the rear of the vehicle is automatically kept
level as you load or unload your vehicle. However,
you should still not exceed the GVWR or the GAWR.
The ignition has to be on for the level control to work.
The system includes a small electric air compressor and
air
-adjustable rear shock absorbers.
You may hear the compressor operating when you load
or unload your vehicle, and periodically as the system
self
-adjusts. This is normal.
ProCarManuals.com

4-46
The compressor should operate for brief periods of time.
If the sound continues for an extended period of time,
your vehicle needs service. To keep your battery from
being drained, you may want to remove the LD LEV
fuse in the engine compartment fuse block until you
can get your vehicle serviced (see ªFuses and Circuit
Breakersº in the Index).
Using heavier suspension components to get added
durability might not change your weight ratings. Ask
your dealer to help you load your vehicle the right way.
Add-On Equipment
When you carry removable items, you may need to put a
limit on how many people you carry inside your vehicle.
Be sure to weigh your vehicle before you buy and install
the new equipment.
NOTICE:
Your warranty doesn't cover parts or components
that fail because of overloading.
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.
ProCarManuals.com

4-47
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 what the vehicle trailering capacity is for
your vehicle, you should read the information in
ªWeight of the Trailerº that appears later in
this section.
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.
ProCarManuals.com

4-48 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.

If you have an automatic transmission, you can
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.
If you have a manual transmission and you are
towing a trailer, it's better not to use FIFTH (5) gear.
Just drive in FOURTH (4) gear (or, as you need to,
a lower gear). See ªTow/Haul Modeº in the Index.
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.
ProCarManuals.com