weight GMC SONOMA 2002 User Guide

4-49
Here is an example of proper truck and camper match:
A. Camper Center of Gravity
B. Recommended Center of Gravity Location Zone
The camper's center of gravity should fall within the
center of gravity zone for your vehicle's cargo load.
Campers can only be installed in a long box pickup.
Check your Truck
-Camper Loading Label on the
passenger's door to determine if your vehicle can carry a
slide
-in camper.
You must weigh any accessories, trailer hitches or other
equipment you add to your vehicle. Then, subtract this
extra weight from the CWR. This extra weight may
shorten the center of gravity zone for your vehicle. Your
dealer can help you with this.If your slide
-in camper and its load weigh less than the
CWR, the center of gravity zone for your vehicle may
be larger.
Your dealer can help you make a good vehicle
-camper
match. He'll also help you determine your CWR.
Secure loose items to prevent weight shifts that could
affect the balance of your vehicle. When the truck
camper is loaded, drive to a scale and weigh on the
front and on the rear wheels separately to determine
axle loads. Individual axle loads should not exceed
either of the Gross Axle Weight Ratings (GAWR).
The total of the axle loads should not exceed the
Gross Vehicle Weight Rating (GVWR). These ratings
are given on the vehicle certification label that is located
on the rear of the passenger's door. If weight ratings are
exceeded, move or remove items to bring all weights
below the ratings.
If you want more information on curb weights, cargo
weights, cargo weight rating and the correct center of
gravity zone for your vehicle, your dealer can help you.
Just ask for a copy of ªConsumer Information,
Truck
-Camper Loading.º

4-50 Trailer Recommendations
You must subtract your hitch load from the CWR for
your vehicle. Weigh your vehicle with your trailer
attached, so that you won't go over the GVWR or the
GAWR.
You'll get the best performance if you spread out the
weight of your load the right way, and if you choose the
correct hitch and trailer brakes.
For more information, see ªTowing a Trailerº later in
this section.
Pickup Conversion to Chassis Cab
General Motors is aware that some vehicle owners may
consider having the pickup box removed and a
commercial or recreational body installed. However, we
recommend that conversions of this type not be done to
pickups. Owners should be aware that, as manufactured,
there are differences between a chassis cab and a pickup
with the box removed which may affect vehicle safety.
For specific information on this pickup, contact GM
Customer Assistance. See ªCustomer Assistanceº in
the Index.
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.

4-51
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.
Your vehicle may be able to tow a trailer. 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.

4-52 If You Do Decide To Pull A Trailer
If you do, here are some important points:

If you have the 2200 L4 (Code 5) engine, use regular
gasoline (without ethanol) when pulling a trailer. See
ªFuelº in the Index.

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 3,500 lbs. (1 589 kg). You should always use
a sway control if your trailer will weigh more than
3,500 lbs. (1 589 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, 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). If you have a manual
transmission and you are towing a trailer, it's better
not to use the highest gear.
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.
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.

4-54
4WD Extended Cab
4.3L V6/Manual Trans. 3.42 4,000 lbs. (1 816 kg)
4.3L V6/Manual Trans. w/ZR2 3.73 4,200 lbs. (1 907 kg)
4.3L V6/Auto. Trans. 3.42 5,500 lbs. (2 497 kg)
3.73 5,500 lbs. (2 497 kg)
4.3L V6/Auto. Trans. w/ZR2 3.73 5,500 lbs. (2 497 kg)
4WD Crew Cab
4.3L V6/Auto. Trans. 3.42 5,200 lbs. (2 361 kg)
3.73 5,200 lbs. (2 361 kg)
* If your vehicle is equipped with RPO V4A (Xtreme
Sport Appearance Package), your vehicle was neither
intended nor designed to tow a trailer. For more information on RPO codes, see ªService Parts Identification Labelº
in the Index.
#If your vehicle is equipped with a code 5 engine you must use regular unleaded gasoline rated at 87 octane or higher
when towing.
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 trailering capacity.
See ªWeight of the Trailer Tongueº later in this section.
**The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be
exceeded.

4-55
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
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.
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.

4-56 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 label at the rear edge of the driver's door
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 use a step
-bumper hitch, your bumper could
be damaged in sharp turns. Make sure you have
ample room when turning to avoid contact between
the trailer and the bumper.

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.

If your vehicle has the bumper delete option, do not
bolt any type of hitch to the close
-out panel. The
close
-out panel will not support a hitch.
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. For
trailers up to 3,500 lbs. (1 589 kg) you may attach the
safety chains to the attaching points on the bumper. For
heavier trailers, follow the trailer or hitch
manufacturer's recommendation for attaching safety
chains. Always leave just enough slack so you can turn
with your rig. Never allow safety chains to drag on the
ground.

4-57 Trailer Brakes
If your trailer weighs more than 1,000 lbs. (450 kg)
loaded, then it needs its own brakes
-- 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 fluid 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
fluid tap at the port on the master cylinder that sends
fluid to the rear brakes. But don't use copper tubing for
this. If you do, it will bend and finally break off. Use
steel brake tubing.
Driving with a Trailer
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.