trailer GMC SONOMA 2003 User Guide

Dinghy Towing
Notice:Towing your vehicle with all four wheels on
the ground will damage drivetrain components.Your two-wheel-drive vehicle should not be towed with
all four wheels on the ground. Your transmission
has no provision for internal lubrication while being
towed. To properly to your vehicle, it 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
must 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. SeeService Publications Ordering
Information on page 7-9.
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 transmissionuid level before driving the vehicle. Two-Wheel Drive Vehicles Only
4-43
2003 - Sonoma OM

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
fuse when you reach your destination. SeeFuses
and Circuit Breakers on page 5-89. Be sure to use the
proper towing equipment designed for recreational
vehicle towing. Follow the instructions for the towing
equipment.
{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) 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 isfirmly set before you shift the transfer
case to NEUTRAL.
If your vehicle has four-wheel-drive it cannot be dinghy
towed. A four-wheel-drive vehicle must be towed by
atbed.
Dolly Towing
Notice:Towing your vehicle with all four wheels on
the ground will damage drivetrain components.
Your two-wheel-drive vehicle should not be towed with
two wheels on the ground. Your transmission has no
provision for internal lubrication while being towed.
To properly tow your vehicle, it 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.Two-Wheel-Drive Vehicles Only
4-44
2003 - Sonoma OM

Loading Your Vehicle
The Certication/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 ination 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 Certication/Tire label also tells you the maximum
weights for the front and rear axles, called Gross
Axle Weight Rating (GAWR). Tond 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.
And, if you do have a heavy load, you should spread
it out.
Similar appearing vehicles may have different GVWRs
and payloads. Please note the Certication/Tire label on
your truck or consult your dealer for additional details.{CAUTION:
In the case of a sudden stop or collision,
things carried in the bed of your truck could
shift forward and come into the passenger
area, injuring you and others. If you put things
in the bed of your truck, you should make sure
they are properly secured.
4-46
2003 - Sonoma OM

The Cargo Weight Rating (CWR) is the maximum
weight of the load your vehicle can carry. It doesn’t
include the weight of the people inside. But, you
cangure about 150 lbs. (68 kg) for each seating
position. The total cargo load must not be more than
your vehicle’s CWR.
Refer to the Truck-Camper Loading Information Label
on the passenger’s door for dimensions A and B as
shown in the following illustration.
Use the rear edge of the loadoor for measurement
purposes. The recommended location for the cargo
center of gravity for the Cargo Weight Rating (C) is the
point where the mass of a body is concentrated and, if
suspended at that point, would balance the front and rear.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.
4-49
2003 - Sonoma OM

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 certication 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“Consumer Information,
Truck-Camper Loading.”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, seeTowing a Trailer on page 4-51
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 specic information on
this pickup, contact GM Customer Assistance. See
Customer Assistance Offices on page 7-4.
4-50
2003 - Sonoma OM

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
“Scheduled Maintenance Services”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“Weight of the Trailer”
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.
4-51
2003 - Sonoma OM

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 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 therst 500 miles
(800 km) your new vehicle is driven. Your engine,
axle or other parts could be damaged.
Then, during therst 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 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.
4-52
2003 - Sonoma OM

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 following chart shows how much your trailer can weigh, based upon your vehicle model and options.
Vehicle* Axle RatioMaximum Trailer
WeightGCWR**
2WD Regular Cab
2.2L L4/Manual Trans. 3.73 1,600 lbs. (726 kg) 5,000 lbs. (2 268 kg)
2.2L L4/Auto. Trans. 4.10 3,100 lbs. (1 406 kg) 6,500 lbs. (2 948 kg)
4.3L V6/Manual Trans. 3.08 3,900 lbs. (1 769 kg) 7,500 lbs. (3 402 kg)
4.3L V6/Auto. Trans. w/ZR2 3.42 5,900 lbs. (2 676 kg) 9,500 lbs. (4 309 kg)
2WD Extended Cab
2.2L L4/Manual Trans. 4.10 2,000 lbs. (907 kg) 5,000 lbs. (2 268 kg)
2.2L L4/Auto. Trans. 4.10 3,000 lbs. (1 362 kg) 6,500 lbs. (2 948 kg)
4.3L V6/Manual Trans. 3.08 3,800 lbs. (1 725 kg) 7,500 lbs. (3 402 kg)
4.3L V6/Auto. Trans 3.42 5,600 lbs. (2 540 kg) 9,500 lbs. (4 309 kg)
2WD Long Box
4.3L V6/Manual Trans. 3.08 3,900 lbs. (1 771 kg) 7,500 lbs. (3 402 kg)
4.3 L V6/Auto Trans. 3.42 5,900 lbs. (2 679 kg) 9, 500 lbs. (4 309 kg)
4-53
2003 - Sonoma OM

Vehicle* Axle RatioMaximum Trailer
WeightGCWR**
4WD Extended Cab
4.3L V6/Manual Trans. 3.42 4,000 lbs (1 816 kg) 8,000 lbs. (3 629 kg)
4.3 L V6/Manual Trans. 3.73 4,200 lbs. (1 907 kg) 8,500 lbs. (3 856 kg)
4.3 L Auto. Trans.3.42
3.735,500 lbs. (2 497 kg)
5,500 lbs. (2 497 kg)9,500 lbs. (4 309 kg)
4.3 L Auto Trans. w/ZR2 3.73 4,700 lbs. (2 132 kg) 9.000 lbs. (4 082 kg)
4WD Crew Cab
®
4.3L V6/Auto. Trans.3.42
3.735,200 lbs. (2 361 kg)
5,200 lbs. (2 361 kg)9,500 lbs. (4 309 kg)
9,500 lbs. (4 309 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, seeService Parts
Identification Label on page 5-88.
Maximum trailer weight is calculated assuming only the
driver is 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″Weight of the Trailer Tongue″next.**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.
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
4-54
2003 - Sonoma OM

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. SeeLoading Your Vehicle
on page 4-46for 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 inated to the upper limit
for cold tires. You’llnd these numbers on the
Certication label at the rear edge of the driver’s door
above the door latch, or seeLoading Your Vehicle
on page 4-46. Then be sure you don’t go over the
GVW limit for your vehicle, including the weight of the
trailer tongue.
4-55
2003 - Sonoma OM