STARTING AND OPERATING 339
rear to front as appropriate until the specified weight limita -
tions are met. Store the heavier items down low and be sure
that the weight is distributed equally. Stow all loose items
securely before driving.
Improper weight distributions can have an adverse effect on
the way your vehicle steers and handles and the way the
brakes operate.
TRAILER TOWING
In this section you will find safety tips and information on
limits to the type of towing you can reasonably do with your
vehicle. Before towing a trailer, carefully review this infor -
mation to tow your load as efficiently and safely as possible.
To maintain the New Vehicle Limited Warranty coverage,
follow the requirements and recommendations in this
manual concerning vehicles used for trailer towing. Common Towing Definitions
The following trailer towing related definitions will assist
you in understanding the following information:
Gross Vehicle Weight Rating (GVWR)
The GVWR is the total allowable weight of your vehicle. This
includes driver, passengers, cargo and tongue weight. The
total load must be limited so that you do not exceed the
GVWR. Refer to “Vehicle Loading/Vehicle Certification
Label” in “Starting And Operating” for further information.
Gross Trailer Weight (GTW)
The GTW is the weight of the trailer plus the weight of all
cargo, consumables and equipment (permanent or tempo -
rary) loaded in or on the trailer in its "loaded and ready for
operation" condition.
The recommended way to measure GTW is to put your fully
loaded trailer on a vehicle scale. The entire weight of the
trailer must be supported by the scale.CAUTION!
Do not load your vehicle any heavier than the GVWR or
the maximum front and rear GAWR. If you do, parts on
your vehicle can break, or it can change the way your
vehicle handles. This could cause you to lose control.
Also overloading can shorten the life of your vehicle. 5
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 in
or 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.
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.
SERVICING AND MAINTENANCE 455
Fuel Economy
Underinflated tires will increase tire rolling resistance
resulting in higher fuel consumption.
Tread Wear
Improper cold tire inflation pressures can cause abnormal
wear patterns and reduced tread life, resulting in the need
for earlier tire replacement.
Ride Comfort And Vehicle Stability
Proper tire inflation contributes to a comfortable ride.
Over-inflation produces a jarring and uncomfortable ride.
Tire Inflation Pressures
The proper cold tire inflation pressure is listed on the driver's
side B-Pillar or rear edge of the driver's side door.
At least once a month:
• Check and adjust tire pressure with a good quality
pocket-type pressure gauge. Do not make a visual judge -
ment when determining proper inflation. Tires may look
properly inflated even when they are under-inflated.
• Inspect tires for signs of tire wear or visible damage. Inflation pressures specified on the placard are always “cold
tire inflation pressure”. Cold tire inflation pressure is
defined as the tire pressure after the vehicle has not been
driven for at least three hours, or driven less than 1 mile
(1.6 km) after sitting for a minimum of three hours. The cold
tire inflation pressure must not exceed the maximum infla -
tion pressure molded into the tire sidewall.
Check tire pressures more often if subject to a wide range of
outdoor temperatures, as tire pressures vary with tempera -
ture changes.
Tire pressures change by approximately 1 psi (7 kPa) per 12°F
(7°C) of air temperature change. Keep this in mind when
checking tire pressure inside a garage, especially in the Winter.
Example: If garage temperature = 68°F (20°C) and the
outside temperature = 32°F (0°C) then the cold tire inflation
pressure should be increased by 3 psi (21 kPa), which equals
1 psi (7 kPa) for every 12°F (7°C) for this outside temperature
condition. CAUTION!
After inspecting or adjusting the tire pressure, always
reinstall the valve stem cap. This will prevent moisture
and dirt from entering the valve stem, which could
damage the valve stem.
7
456 SERVICING AND MAINTENANCE
Tire pressure may increase from 2 to 6 psi (13 to 40 kPa)
during operation. DO NOT reduce this normal pressure
build up or your tire pressure will be too low.
Tire Pressures For High Speed Operation
The manufacturer advocates driving at safe speeds and
within posted speed limits. Where speed limits or conditions
are such that the vehicle can be driven at high speeds, main -
taining correct tire inflation pressure is very important.
Increased tire pressure and reduced vehicle loading may be
required for high-speed vehicle operation. Refer to an autho -
rized tire dealer or original equipment vehicle dealer for
recommended safe operating speeds, loading and cold tire
inflation pressures. Radial Ply Tires
Tire Repair
If your tire becomes damaged, it may be repaired if it meets
the following criteria:
• The tire has not been driven on when flat.
• The damage is only on the tread section of your tire (side -
wall damage is not repairable).
• The puncture is no greater than a ¼ of an inch (6 mm).
Consult an authorized tire dealer for tire repairs and addi -
tional information.
Damaged Run Flat tires, or Run Flat tires that have experi -
enced a loss of pressure should be replaced immediately
with another Run Flat tire of identical size and service
description (Load Index and Speed Symbol). Replace the tire
pressure sensor as well as it is not designed to be reused.WARNING!
High speed driving with your vehicle under maximum
load is dangerous. The added strain on your tires could
cause them to fail. You could have a serious collision. Do
not drive a vehicle loaded to the maximum capacity at
continuous speeds above 75 mph (120 km/h). WARNING!
Combining radial ply tires with other types of tires on
your vehicle will cause your vehicle to handle poorly.
The instability could cause a collision. Always use radial
ply tires in sets of four. Never combine them with other
types of tires.
460 SERVICING AND MAINTENANCE
Tire Types
All Season Tires — If Equipped
All Season tires provide traction for all seasons (Spring,
Summer, Fall, and Winter). Traction levels may vary
between different all season tires. All season tires can be
identified by the M+S, M&S, M/S or MS designation on the
tire sidewall. Use all season tires only in sets of four; failure
to do so may adversely affect the safety and handling of your
vehicle. Summer Or Three Season Tires — If Equipped
Summer tires provide traction in both wet and dry condi -
tions, and are not intended to be driven in snow or on ice. If
your vehicle is equipped with Summer tires, be aware these
tires are not designed for Winter or cold driving conditions.
Install Winter tires on your vehicle when ambient tempera -
tures are less than 40°F (5°C) or if roads are covered with ice
or snow. For more information, contact an authorized dealer.
Summer tires do not contain the all season designation or
mountain/snowflake symbol on the tire sidewall. Use
Summer tires only in sets of four; failure to do so may
adversely affect the safety and handling of your vehicle.• Never use a tire with a smaller load index or capacity,
other than what was originally equipped on your
vehicle. Using a tire with a smaller load index could
result in tire overloading and failure. You could lose
control and have a collision.
• Failure to equip your vehicle with tires having
adequate speed capability can result in sudden tire
failure and loss of vehicle control.
CAUTION!
Replacing original tires with tires of a different size may
result in false speedometer and odometer readings. WARNING! (Continued)
WARNING!
Do not use Summer tires in snow/ice conditions. You
could lose vehicle control, resulting in severe injury or
death. Driving too fast for conditions also creates the
possibility of loss of vehicle control.
SERVICING AND MAINTENANCE 461
Snow Tires
Some areas of the country require the use of snow tires
during the Winter. Snow tires can be identified by a “moun -
tain/snowflake” symbol on the tire sidewall.
If you need snow tires, select tires equivalent in size
and type to the original equipment tires. Use snow
tires only in sets of four; failure to do so may
adversely affect the safety and handling of your vehicle.
Snow tires generally have lower speed ratings than what was
originally equipped with your vehicle and should not be
operated at sustained speeds over 75 mph (120 km/h). For
speeds above 75 mph (120 km/h) refer to original equipment
or an authorized tire dealer for recommended safe operating
speeds, loading and cold tire inflation pressures.
While studded tires improve performance on ice, skid and
traction capability on wet or dry surfaces may be poorer than
that of non-studded tires. Some states prohibit studded tires;
therefore, local laws should be checked before using these
tire types. Spare Tires — If Equipped
NOTE:
For vehicles equipped with Tire Service Kit instead of a spare
tire, please refer to “Tire Service Kit” in “In Case Of Emer -
gency” for further information.
Refer to the “Towing Requirements - Tires” in “Starting And
Operating” for restrictions when towing with a spare tire
designated for temporary emergency use.
Spare Tire Matching Original Equipped Tire And Wheel
— If Equipped
Your vehicle may be equipped with a spare tire and wheel
equivalent in look and function to the original equipment
tire and wheel found on the front or rear axle of your vehicle.
This spare tire may be used in the tire rotation for your
vehicle. If your vehicle has this option, refer to an authorized
tire dealer for the recommended tire rotation pattern. CAUTION!
Because of the reduced ground clearance, do not take
your vehicle through an automatic car wash with a
compact or limited use temporary spare installed.
Damage to the vehicle may result.
7
SERVICING AND MAINTENANCE 465
Dark Vapor Chrome, Black Satin Chrome, or Low Gloss
Clear Coat Wheels
Tire Chains (Traction Devices)
Use of traction devices require sufficient tire-to-body clear -
ance. Follow these recommendations to guard against
damage.
• Traction device must be of proper size for the tire, as
recommended by the traction device manufacturer.
Please follow the table below for proper tire size, chain type,
and axle recommendations:CAUTION!
If your vehicle is equipped with these specialty wheels,
DO NOT USE wheel cleaners, abrasives, or polishing
compounds. They will permanently damage this finish
and such damage is not covered by the New Vehicle
Limited Warranty. HAND WASH ONLY USING MILD
SOAP AND WATER WITH A SOFT CLOTH. Used on a
regular basis; this is all that is required to maintain this
finish.
Vehicle Axle Recommendations Tire Sizes Chain Class
Chassis Cab 3500 (Single Rear
Wheel) Models Rear Only LT275/70R18E U Class
Chassis Cab 3500 (Dual Rear
Wheel) 4X2 Models Rear Only LT235/80R17E U Class
Chassis Cab 3500 (Dual Rear
Wheel) 4X4 Models Front/Rear LT235/80R17E U Class
Chassis Cab 4500/5500 Models Rear Only 225/70R19.5G U Class 7