weight GMC SONOMA 2004 Owner's Guide

The trailer tongue weight (A) should be 10 percent to
15 percent of the total loaded trailer weight, up to
a maximum of 5,200 lbs (2 361 kg) with a weight
carrying hitch. The trailer tongue weight (A) should be
10 percent to 15 percent of the total loaded trailer
weight, up to a maximum of 5,200 lbs (2 361 kg) with a
weight distributing hitch.Do not exceed the maximum allowable tongue weight
for your vehicle. Choose the shortest hitch extension
that will position the hitch ball closest to the vehicle. This
will help reduce the effect of trailer tongue weight on
the rear axle.
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 label at the rear edge of the driver’s door
above the door latch, or seeLoading Your Vehicle
on page 4-45. Then be sure you don’t go over the GVW
limit for your vehicle, including the weight of the trailer
tongue. If you use a weight distributing hitch, make sure
you don’t go over the rear axle limit before you apply
the weight distribution spring bars.
4-58

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.
Weight-Distributing Hitches and Weight
Carrying Hitches
When using a weight-distributing hitch, the hitch must
be adjusted so that the distance (A) remains the
same both before and after coupling the trailer tow
vehicle.
If you use a step-bumper hitch, your bumper could be
damaged by sharp turns. Make sure you have ample
room when turning to avoid contact between the trailer
and the bumper.
4-59

If you’ll be pulling a trailer, that when loaded, will weigh
more than 5,000 lbs (2 270 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 driving. You should always use a sway control
if your traile will weigh more than these limits. You can
ask a hitch dealer about sway controls.
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.
Trailer Brakes
If your trailer weighs more than 1,000 lbs. (450 kg)
loaded, then it needs its own brake–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.
4-60

(A) Light Truck (LT-Metric) Tire:The United States
version of a metric tire sizing system. The letter “LT” as
the first two characters in the tire size means a light
truck tire engineered to standards set by the U. S. Tire
and Rim Association.
(B) Tire Width:The three-digit number indicates the
tire section width in millimeters from sidewall to sidewall.
(C) Aspect Ratio:A two-digit number that indicates
the tire height-to-width measurements. For example, if
the tire size aspect ratio is “75,” as shown in item “C” of
the illustration, it would mean that the tire’s sidewall is
75% as high as it is wide.(D) Construction Code:A letter code is used to
indicate the type of ply construction in the tire. The letter
“R” means radial ply construction; the letter “D” means
diagonal or bias ply construction; and the letter “B”
means belted-bias ply construction.
(E) Rim Diameter:Diameter of the wheel in inches.
(F) Service Description:The service description
indicates the load range and speed rating of a tire. The
load index can range from 1 to 279. Speed ratings
range from “A” to “Z”. The light truck tire size example
above shows dual or single tire configurations.Tire Terminology and Denitions
Air Pressure:The amount of air inside the tire pressing
outward on each square inch of the tire. Air pressure
is expressed in pounds per square inch (psi) or
kilopascal (kPa).
Accessory Weight:This means the combined weight
of optional accessories. Some examples of optional
accessories are, automatic transmission, power steering,
power brakes, power windows, power seats, and air
conditioning.
Aspect Ratio:The relationship of a tire’s height to its
width. Light Truck (LT-Metric) Tire
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Belt:A rubber coated layer of cords that is located
between the plies and the tread. Cords may be made
from steel or other reinforcing materials.
Bead:The tire bead contains steel wires wrapped by
steel cords that hold the tire onto the rim.
Bias Ply Tire:A pneumatic tire in which the plies are
laid at alternate angles less than 90 degrees to the
centerline of the tread.
Cold Ination Pressure:The amount of air pressure in
a tire, measured in pounds per square inch (psi) or
kilopascals (kPa) before a tire has built up heat
from driving. SeeInation - Tire Pressure on page 5-67.
Curb Weight:This means the weight of a motor
vehicle with standard and optional equipment including
the maximum capacity of fuel, oil and coolant, but
without passengers and cargo.
DOT Markings:A code molded into the sidewall of a
tire signifying that the tire is in compliance with the U.S.
Department of Transportation motor vehicle safety
standards. The DOT code includes the Tire Identification
Number (TIN), an alphanumeric designator which can
also identify the tire manufacturer, production plant,
brand and date of production.GVWR:Gross Vehicle Weight Rating, seeLoading
Your Vehicle on page 4-45.
GAWR FRT:Gross Axle Weight Rating for the front
axle, seeLoading Your Vehicle on page 4-45.
GAWR RR:Gross Axle Weight Rating for the rear axle,
seeLoading Your Vehicle on page 4-45.
Intended Outboard Sidewall:The side of an
asymmetrical tire, that must always face outward when
mounted on a vehicle.
Kilopascal (kPa):The metric unit for air pressure.
There are 6.9 kPa’s to one psi.
Light Truck (LT-Metric) Tire:A tire used on light duty
trucks and some multipurpose passenger vehicles.
Load Index:An assigned number ranging from 1 to 279
that corresponds to the load carrying capacity of
a tire.
Maximum Ination Pressure:The maximum air
pressure to which a cold tire may be inflated. The
maximum air pressure is molded onto the sidewall.
Maximum Load Rating:The load rating for a tire at the
maximum permissible inflation pressure for that tire.
5-65

Maximum Loaded Vehicle Weight:The sum of curb
weight; accessory weight; vehicle capacity weight;
and production options weight.
Normal Occupant Weight:The number of occupants a
vehicle is designed to seat multiplied by 150 pounds
(68 kg). SeeLoading Your Vehicle on page 4-45.
Occupant Distribution:Designated seating positions.
Outward Facing Sidewall:The side of a asymmetrical
tire that has a particular side that faces outward
when mounted on a vehicle. The side of the tire that
contains a whitewall, bears white lettering or bears
manufacturer, brand and or model name molding that is
higher or deeper than the same moldings on the
other sidewall of the tire.
Passenger (P-Metric) Tire:A tire used on passenger
cars and some light duty trucks and multipurpose
vehicles.
Recommended Ination Pressure:Vehicle
manufacturer’s recommended tire inflation pressure and
shown on the tire placard. SeeInation - Tire Pressure
on page 5-67andLoading Your Vehicle on page 4-45.
Radial Ply tire:A pneumatic tire in which the ply cords
that extend to the beads are laid at 90 degrees to the
centerline of the tread.Rim:A metal support for a tire and upon which the tire
beads are seated.
Sidewall:The portion of a tire between the tread and
the bead.
Speed Rating:An alphanumeric code assigned to a
tire indicating the maximum speed at which a tire
can operate.
Traction:The friction between the tire and the road
surface. The amount of grip provided.
Tread:The portion of a tire that comes into contact
with the road.
Treadwear Indicators:Narrow bands, sometimes
called “wear bars,” that show across the tread of a tire
when only 2/32 inch of tread remains. SeeWhen It
Is Time for New Tires on page 5-69.
UTQGS:Uniform Tire Quality Grading Standards, a tire
information system that provides consumers with
ratings for a tire’s traction, temperature and treadwear.
Ratings are determined by tire manufacturers using
government testing procedures. The ratings are molded
into the sidewall of the tire. SeeUniform Tire Quality
Grading on page 5-71.
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Vehicle Capacity Weight:The number of designated
seating positions multiplied by 150 lbs. (68 kg) plus
the rated cargo load. SeeLoading Your Vehicle
on page 4-45.
Vehicle Maximum Load on the Tire:Load on an
individual tire due to curb weight, accessory weight,
occupant weight and cargo weight.
Vehicle Placard:A label permanently attached to a
vehicle showing the original equipment tire size
and recommended inflation pressure. SeeLoading Your
Vehicle on page 4-45.
Ination - Tire Pressure
The tire and loading information label, shows the correct
inflation pressures for your tires when they’re cold.
“Cold” means your vehicle has been sitting for at least
three hours or driven no more than 1 mile (1.6 km). See
Loading Your Vehicle on page 4-45, for the location
of your vehicle’s tire and loading information label.
Notice:Don’t let anyone tell you that underination
or overination is all right. It’s not. If your tires
don’t have enough air (underination), you can get
the following:
Too much exing
Too much heat
Tire overloading
Bad wear
Bad handling
Bad fuel economy
If your tires have too much air (overination), you
can get the following:
Unusual wear
Bad handling
Rough ride
Needless damage from road hazards
When to Check
Check your tires once a month or more.
Also, check the tire pressure of the spare tire.
If you have a compact spare tire, it should be at
60 psi (420 kPa).
How to Check
Use a good quality pocket-type gage to check tire
pressure. You can’t tell if your tires are properly inflated
simply by looking at them. Radial tires may look
properly inflated even when they’re underinflated. Check
the tire’s inflation pressure when the tires are cold.
cold means your vehicle has been sitting for at least
three hours or driven no more than 1 mile (1.6 km).
5-67

Total Weight on Your Vehicle’s Tires..................4-58
Towing
Recreational Vehicle.....................................4-45
Towing a Trailer..........................................4-55
Your Vehicle...............................................4-45
Trailer
Recommendations.......................................4-54
Trailer Brakes.................................................4-60
Transfer Case........................................2-23, 5-46
Transfer Case and Front Axle
(Four-Wheel Drive) Inspection.......................6-31
Transmission
Fluid, Automatic...........................................5-19
Transmission Operation, Automatic....................2-20
Transmission, Transaxle, Transfer Case Unit
Repair Manual............................................7-12
Transportation Options...................................... 7-8
Traveling to Remote Areas...............................4-16
Trip Odometer................................................3-24
Truck-Camper Loading Information....................4-52
Turn and Lane-Change Signals.......................... 3-6
Turn Signal/Multifunction Lever........................... 3-6
Turn Signals When Towing a Trailer..................4-61
Two-Piece Composite Headlamp System............5-50
Two-Tiered Loading.........................................4-51U
Underbody Flushing Service.............................6-29
Understanding Radio Reception........................3-74
Uniform Tire Quality Grading............................5-71
United States................................................... 7-4
Used Replacement Wheels..............................5-73
Using Cleaner on Fabric..................................5-87
Using Song List Mode.....................................3-71
Using the Recovery Hooks...............................4-43
V
Vehicle
Control........................................................ 4-5
Damage Warnings........................................... iv
Loading......................................................4-45
Symbols......................................................... iv
Vehicle Data Collection and Event
Data Records............................................... 7-9
Vehicle Identification
Number (VIN).............................................5-94
Service Parts Identification Label...................5-94
Vehicle Storage..............................................5-41
Ventilation Adjustment......................................3-20
Visors...........................................................2-14
Voltmeter Gage..............................................3-26
15

W
Warning Lights, Gages and Indicators................3-21
Warnings
Hazard Warning Flashers............................... 3-4
Other Warning Devices.................................. 3-5
Safety and Symbols......................................... iii
Vehicle Damage.............................................. iv
Washing Your Vehicle......................................5-89
Weatherstrip Lubrication...................................6-26
Weight of the Trailer........................................4-56
Weight of the Trailer Tongue.............................4-57
Weight-Distributing Hitches and Weight
Carrying Hitches..........................................4-59
What Kind of Engine Oil to Use........................5-14
What to Add..................................................5-38
What to Do with Used Oil................................5-17
What to Use..........................5-24, 5-36, 5-46, 5-48
Wheels
Alignment and Tire Balance..........................5-72
Replacement...............................................5-72
When to Add Engine Oil..................................5-14
When to Change Engine Oil.............................5-16
When to Check..............................................5-67
When to Check and Change Lubricant.......5-46, 5-47
When to Check and Change the Automatic
Transmission Fluid.......................................5-19
When to Check Power Steering Fluid................5-35
When to Inspect the Engine Air Cleaner/Filter.....5-18When You Are Ready to Leave After
Parking on a Hill.........................................4-63
Where to Put the Restraint...............................1-36
Why Safety Belts Work..................................... 1-9
Window Lockout.............................................2-13
Windows.......................................................2-12
Manual......................................................2-12
Power........................................................2-13
Sliding Rear................................................2-14
Windshield Washer
Fluid..........................................................5-36
Windshield Washer Fluid Level Check................6-25
Windshield Wiper
Blade Replacement......................................5-54
Fuses........................................................5-95
Windshield Wipers............................................ 3-8
Winter Driving................................................4-38
Wiper Blade Check.........................................6-26
X
XM™ Satellite Radio Antenna System................3-76
XM™ Satellite Radio Service
(48 Contiguous US States)...........3-39, 3-60, 3-74
Y
Your Vehicle and the Environment....................... 6-2
16