338 STARTING AND OPERATING
Payload
The payload of a vehicle is defined as the allowable load
weight a truck can carry, including the weight of the driver,
all passengers, options and cargo.
Gross Axle Weight Rating (GAWR)
The GAWR is the maximum permissible load on the front
and rear axles. The load must be distributed in the cargo area
so that the GAWR of each axle is not exceeded.
Each axle GAWR is determined by the components in the
system with the lowest load carrying capacity (axle, springs,
tires or wheels). Heavier axles or suspension components
sometimes specified by purchasers for increased durability
does not necessarily increase the vehicle's GVWR.
Tire Size
The tire size on the Vehicle Certification Label represents the
actual tire size on your vehicle. Replacement tires must be
equal to the load capacity of this tire size.
Rim Size
This is the rim size that is appropriate for the tire size listed.
Inflation Pressure
This is the cold tire inflation pressure for your vehicle for all
loading conditions up to full GAWR.
Curb Weight
The curb weight of a vehicle is defined as the total weight of
the vehicle with all fluids, including vehicle fuel, at full
capacity conditions, and with no occupants or cargo loaded
into the vehicle. The front and rear curb weight values are
determined by weighing your vehicle on a commercial scale
before any occupants or cargo are added.
Loading
The actual total weight and the weight of the front and rear
of your vehicle at the ground can best be determined by
weighing it when it is loaded and ready for operation.
The entire vehicle should first be weighed on a commercial
scale to insure that the GVWR has not been exceeded. The
weight on the front and rear of the vehicle should then be
determined separately to be sure that the load is properly
distributed over the front and rear axle. Weighing the vehicle
may show that the GAWR of either the front or rear axles has
been exceeded but the total load is within the specified
GVWR. If so, weight must be shifted from front to rear or
340 STARTING AND OPERATING
Gross Combination Weight Rating (GCWR)
The GCWR is the total allowable weight of your vehicle and
trailer when weighed in combination.
Gross Axle Weight Rating (GAWR)
The GAWR is the maximum capacity of the front and rear
axles. Distribute the load over the front and rear axles evenly.
Make sure that you do not exceed either front or rear GAWR.
Refer to “Vehicle Loading/Vehicle Certification Label” in
“Starting And Operating” for further information.Tongue Weight (TW)
The tongue weight is the downward force exerted on the
hitch ball by the trailer. You must consider this as part of the
load on your vehicle.
Trailer Frontal Area
The frontal area is the maximum height multiplied by the
maximum width of the front of a trailer.
Trailer Sway Control
The trailer sway control can be a mechanical telescoping link
that can be installed between the hitch receiver and the
trailer tongue that typically provides adjustable friction asso
-
ciated with the telescoping motion to dampen any unwanted
trailer swaying motions while traveling.
If equipped, the electronic Trailer Sway Control (TSC) recog -
nizes a swaying trailer and automatically applies individual
wheel brakes and/or reduces engine power to attempt to
eliminate the trailer sway.
WARNING!
If the gross trailer weight is 5,000 lbs (2,267 kg) or more,
it is recommended to use a weight-distributing hitch to
ensure stable handling of your vehicle. If you use a
standard weight-carrying hitch, you could lose control of
your vehicle and cause a collision.
WARNING!
It is important that you do not exceed the maximum front
or rear GAWR. A dangerous driving condition can result
if either rating is exceeded. You could lose control of the
vehicle and have a collision.
342 STARTING AND OPERATING
With Weight-Distributing Hitch (Correct)Improper Adjustment Of Weight-Distributing Hitch
(Incorrect)
Recommended Distribution Hitch Adjustment
1. Position the truck to be ready to connect to the trailer (do not connect the trailer).
2. Measure the height of the top of the front wheel opening on the fender to ground, this is height H1.
STARTING AND OPERATING 343
Measuring Height (H)
3. Attach the trailer to the vehicle without the weight distri -
bution bars connected.
4. Measure the height of the top of the front wheel opening on the fender to ground, this is height H2.
5. Install and adjust the tension in the weight distributing bars per the manufacturers’ recommendations so that the
height of the front fender is approximately (H2-H1)/
2+H1 (about 1/2 the difference between H2 and H1 above
normal ride height [H1]). 6. Preform a visual inspection of the trailer and weight
distributing hitch to confirm manufacturers’ recommen -
dations have been met.
NOTE:
For all towing conditions, we recommend towing with tow
haul mode engaged.
Fifth-Wheel Hitch
The fifth-wheel hitch is a special high platform with a
coupling that mounts over the rear axle of the tow vehicle in
the truck bed. It connects a vehicle and fifth-wheel trailer
with a coupling king pin.
Your truck may be equipped with a 5th wheel hitch option.
Refer to the separately provided 5th wheel hitch safety, care,
assembly, and operating instructions.
Measurement Example Example 2500/3500 Height
(mm)
H1 1030
H2 1058
H2-H1 28
(H2-H1)/2 14
(H2-H1)/2 + H1 1044
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344 STARTING AND OPERATING
Gooseneck Hitch
The gooseneck hitch employs a pivoted coupling arm which
attaches to a ball mounted in the bed of a pickup truck. The
coupling arm connects to the hitch mounted over the rear
axle in the truck bed.Trailer Hitch Type and Maximum Trailer Weight
The following chart provides the industry standard for the
maximum trailer weight a given trailer hitch class can tow
and should be used to assist you in selecting the correct
trailer hitch for your intended towing condition.
Trailer Hitch Classification Definitions
Class Max. Trailer Hitch Industry Standards
Class I - Light Duty 2,000 lbs (907 kg)
Class II - Medium Duty 3,500 lbs (1,587 kg)
Class III - Heavy Duty 5,000 lbs (2,267 kg)
Class IV - Extra Heavy Duty 10,000 lbs (4,535 kg)
Fifth Wheel/Gooseneck Greater than 10,000 lbs (4,535 kg)
Refer to the “Trailer Towing Weights (Maximum Trailer Weight Ratings)” for the Maximum Gross Trailer Weight (GTW)
towable for your given drivetrain.
All trailer hitches should be professionally installed on your vehicle.
346 STARTING AND OPERATING
Consider the following items when computing the weight on
the rear axle of the vehicle:
• The tongue weight of the trailer.
• The weight of any other type of cargo or equipment put inor on your vehicle.
• The weight of the driver and all passengers.
NOTE:
Remember that everything put into or on the trailer adds to
the load on your vehicle. Also, additional factory-installed
options or dealer-installed options must be considered as
part of the total load on your vehicle. Refer to the “Tire And
Loading Information” placard for the maximum combined
weight of occupants and cargo for your vehicle.
Towing Requirements
To promote proper break-in of your new vehicle drivetrain
components, the following guidelines are recommended.
Perform the maintenance listed in the “Scheduled
Servicing”. Refer to “Scheduled Servicing” in “Servicing
And Maintenance” for the proper maintenance intervals.
When towing a trailer, never exceed the GAWR or GCWR
ratings.
CAUTION!
Always load a trailer with 60% of the weight in the front
of the trailer. This places 10% of the GTW on the tow
hitch of your vehicle. Loads balanced over the wheels or
heavier in the rear can cause the trailer to sway severely
side to side which will cause loss of control of the vehicle
and trailer. Failure to load trailers heavier in front is the
cause of many trailer collisions.
CAUTION!
• Do not tow a trailer at all during the first 500 miles (805 km) the new vehicle is driven. The engine, axle or
other parts could be damaged.
• Then, during the first 500 miles (805 km) that a trailer is towed, do not drive over 50 mph (80 km/h) and do not
make starts at full throttle. This helps the engine and
other parts of the vehicle wear in at the heavier loads.
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(Continued)
Towing Requirements — Tires
• Do not attempt to tow a trailer while using a compact sparetire.
• Do not drive more than 50 mph (80 km/h) when towing while using a full size spare tire.
WARNING!
• Make certain that the load is secured in the trailer and will not shift during travel. When trailering cargo that
is not fully secured, dynamic load shifts can occur that
may be difficult for the driver to control. You could lose
control of your vehicle and have a collision.
• When hauling cargo or towing a trailer, do not overload your vehicle or trailer. Overloading can cause a loss of
control, poor performance or damage to brakes, axle,
engine, transmission, steering, suspension, chassis
structure or tires.
• Safety chains must always be used between your vehicle and trailer. Always connect the chains to the
hook retainers of the vehicle hitch. Cross the chains
under the trailer tongue and allow enough slack for
turning corners.
• Vehicles with trailers should not be parked on a grade. When parking, apply the parking brake on the tow
vehicle. Put the tow vehicle transmission in PARK. For
four-wheel drive vehicles, make sure the transfer case
is not in NEUTRAL. Always, block or "chock" the
trailer wheels.
• GCWR must not be exceeded.
• Total weight must be distributed between the tow vehicle and the trailer such that the following four
ratings are not exceeded:
• GVWR
• GTW
• GAWR
• Tongue weight rating for the trailer hitch utilized.
WARNING! (Continued)
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350 STARTING AND OPERATING
GAIN Adjustment Buttons (+/-)
Pushing these buttons will adjust the brake control power
output to the trailer brakes in 0.5 increments. The GAIN
setting can be increased to a maximum of 10 or decreased to
a minimum of 0 (no trailer braking).
GAIN
The GAIN setting is used to set the trailer brake control for
the specific towing condition and should be changed as
towing conditions change. Changes to towing conditions
include trailer load, vehicle load, road conditions and
weather.
Adjusting GAIN
NOTE:
This should only be performed in a traffic free environment
at speeds of approximately 20–25 mph (30–40 km/h).
1. Make sure the trailer brakes are in good working condi-
tion, functioning normally and properly adjusted. See
your trailer dealer if necessary.
2. Hook up the trailer and make the electrical connections according to the trailer manufacturer's instructions. 3. When a trailer with electric/EOH brakes is plugged in,
the trailer connected message should appear in the
instrument cluster display (if the connection is not recog -
nized by the ITBM, braking functions will not be avail -
able), the GAIN setting will illuminate and the correct
type of trailer must be selected from the instrument
cluster display options.
4. Push the UP or DOWN button on the steering wheel until “TRAILER TOW” appears on the screen.
5. Push the RIGHT arrow on the steering wheel to enter “TRAILER TOW”.
6. Push the UP or DOWN buttons until the Trailer Brake Type appears on the screen.
7. Push the RIGHT arrow and then push the UP or DOWN buttons until the proper Trailer Brake Type appears on
the screen.
8. In a traffic-free environment, tow the trailer on a dry, level surface at a speed of 20–25 mph (30–40 km/h) and
squeeze the manual brake control lever completely.
9. If the trailer wheels lockup (indicated by squealing tires), reduce the GAIN setting; if the trailer wheels turn freely,
increase the GAIN setting.