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 in-
creased durability does not necessarily increase the vehi-
cle’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 rear to front as appropriate until the specified
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STARTING AND OPERATING 289
Life Of Tire
The service life of a tire is dependent upon varying factors
including, but not limited to:
•Driving style.
• Tire pressure - Improper cold tire inflation pressures can
cause uneven wear patterns to develop across the tire
tread. These abnormal wear patterns will reduce tread
life, resulting in the need for earlier tire replacement.
• Distance driven.
• Performance tires, tires with a speed rating of V or
higher, and Summer tires typically have a reduced tread
life. Rotation of these tires per the vehicle scheduled
maintenance is highly recommended.
WARNING!
Tires and the spare tire should be replaced after six
years, regardless of the remaining tread. Failure to
follow this warning can result in sudden tire failure.
You could lose control and have a collision resulting in
serious injury or death. Keep dismounted tires in a cool, dry place with as little
exposure to light as possible. Protect tires from contact with
oil, grease, and gasoline.
Replacement Tires
The tires on your new vehicle provide a balance of many
characteristics. They should be inspected regularly for
wear and correct cold tire inflation pressures. The manu-
facturer strongly recommends that you use tires equivalent
to the originals in size, quality and performance when
replacement is needed. Refer to the paragraph on “Tread
Wear Indicators” in this section. Refer to the Tire and
Loading Information placard or the Vehicle Certification
Label for the size designation of your tire. The Load Index
and Speed Symbol for your tire will be found on the
original equipment tire sidewall.
See the Tire Sizing Chart example found in the “Tire Safety
Information” section of this manual for more information
relating to the Load Index and Speed Symbol of a tire.
It is recommended to replace the two front tires or two rear
tires as a pair. Replacing just one tire can seriously affect
your vehicle’s handling. If you ever replace a wheel, make
sure that the wheel’s specifications match those of the
original wheels.
406 SERVICING AND MAINTENANCE
It is recommended you contact your authorized tire dealer
or original equipment dealer with any questions you may
have on tire specifications or capability. Failure to use
equivalent replacement tires may adversely affect the
safety, handling, and ride of your vehicle.
WARNING!
•Do not use a tire, wheel size, load rating, or speed
rating other than that specified for your vehicle.
Some combinations of unapproved tires and wheels
may change suspension dimensions and perfor-
mance characteristics, resulting in changes to steer-
ing, handling, and braking of your vehicle. This can
cause unpredictable handling and stress to steering
and suspension components. You could lose control
and have a collision resulting in serious injury or
death. Use only the tire and wheel sizes with load
ratings approved for 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.
(Continued)
WARNING! (Continued)
•Failure to equip your vehicle with tires having ad-
equate 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 read-
ings.
Tire Types
All Season Tires — If Equipped
All Season tires provide traction for all seasons (Spring,
Summer, Fall, and Winter). Traction levels may vary be-
tween 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.
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SERVICING AND MAINTENANCE 407
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 Emergency” for further information.
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.
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.
Compact Spare Tire — If Equipped
The compact spare is for temporary emergency use only.
You can identify if your vehicle is equipped with a compact spare by looking at the spare tire description on the Tire
and Loading Information Placard located on the driver ’s
side door opening or on the sidewall of the tire. Compact
spare tire descriptions begin with the letter “T” or “S”
preceding the size designation. Example: T145/80D18
103M.
T, S = Temporary Spare Tire
Since this tire has limited tread life, the original equipment
tire should be repaired (or replaced) and reinstalled on
your vehicle at the first opportunity.
Do not install a wheel cover or attempt to mount a
conventional tire on the compact spare wheel, since the
wheel is designed specifically for the compact spare tire.
Do not install more than one compact spare tire and wheel
on the vehicle at any given time.
WARNING!
Compact and collapsible spares are for temporary
emergency use only. With these spares, do not drive
more than 50 mph (80 km/h). Temporary use spares
have limited tread life. When the tread is worn to the
tread wear indicators, the temporary use spare tire
(Continued)
8
SERVICING AND MAINTENANCE 409
WARNING!(Continued)
needs to be replaced. Be sure to follow the warnings,
which apply to your spare. Failure to do so could result
in spare tire failure and loss of vehicle control.
Collapsible Spare Tire — If Equipped
The collapsible spare is for temporary emergency use only.
You can identify if your vehicle is equipped with a collaps-
ible spare by looking at the spare tire description on the
Tire and Loading Information Placard located on the
driver ’s side door opening or on the sidewall of the tire.
Collapsible spare tire description example: 165/80-17 101P.
Since this tire has limited tread life, the original equipment
tire should be repaired (or replaced) and reinstalled on
your vehicle at the first opportunity.
Inflate collapsible tire only after the wheel is properly
installed to the vehicle. Inflate the collapsible tire using the
electric air pump before lowering the vehicle.
Do not install a wheel cover or attempt to mount a
conventional tire on the collapsible spare wheel, since the
wheel is designed specifically for the collapsible spare tire.
WARNING!
Compact and Collapsible spares are for temporary
emergency use only. With these spares, do not drive
more than 50 mph (80 km/h). Temporary use spares
have limited tread life. When the tread is worn to the
tread wear indicators, the temporary use spare tire
needs to be replaced. Be sure to follow the warnings,
which apply to your spare. Failure to do so could result
in spare tire failure and loss of vehicle control.
Full Size Spare — If Equipped
The full size spare is for temporary emergency use only.
This tire may look like the originally equipped tire on the
front or rear axle of your vehicle, but it is not. This spare
tire may have limited tread life. When the tread is worn to
the tread wear indicators, the temporary use full size spare
tire needs to be replaced. Since it is not the same as your
original equipment tire, replace (or repair) the original
equipment tire and reinstall on the vehicle at the first
opportunity.
410 SERVICING AND MAINTENANCE
When cleaning extremely dirty wheels including excessive
brake dust, care must be taken in the selection of tire and
wheel cleaning chemicals and equipment to prevent dam-
age to the wheels. Mopar Wheel Treatment or Mopar
Chrome Cleaner or their equivalent is recommended or
select a non-abrasive, non-acidic cleaner for aluminum or
chrome wheels.
CAUTION!
Do not use scouring pads, steel wool, a bristle brush,
metal polishes or oven cleaner. These products may
damage the wheel’s protective finish. Such damage is
not covered by the New Vehicle Limited Warranty.
Only car wash soap, Mopar Wheel Cleaner or equiva-
lent is recommended.
NOTE: If you intend parking or storing your vehicle for an
extended period after cleaning the wheels with wheel
cleaner, drive your vehicle and apply the brakes to remove
the water droplets from the brake components. This activ-
ity will remove the red rust on the brake rotors and prevent
vehicle vibration when braking. Dark Vapor Chrome, Black Satin Chrome, or Low Gloss
Clear Coat Wheels
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 US-
ING MILD SOAP AND WATER WITH A SOFT
CLOTH. Used on a regular basis; this is all that is
required to maintain this finish.
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.
412 SERVICING AND MAINTENANCE
Please follow the table below for proper tire size, chain type, and axle recommendations:
VehicleAxle Recommendations Tire SizesChain 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
WARNING!
Using tires of different size and type (M+S, Snow)
between front and rear axles can cause unpredictable
handling. You could lose control and have a collision.
CAUTION!
To avoid damage to your vehicle or tires, observe the
following precautions:
•Because of restricted traction device clearance be-
tween tires and other suspension components, it is
important that only traction devices in good condi-
tion are used. Broken devices can cause serious
damage. Stop the vehicle immediately if noise occurs
that could indicate device breakage. Remove the
damaged parts of the device before further use.
(Continued)
8
SERVICING AND MAINTENANCE 413
Hydraulic Brake Assist
The brake system power assist is provided by a hydro-
boost unit which shares fluid with the power steering
system. You may experience some clicking or hissing
noises from the hydro-boost system during hard braking
conditions.
NOTE:Under cold temperatures, pedal effort will be
higher than normal until the power steering fluid reaches
operating temperature.
WHEEL AND TIRE TORQUE SPECIFICATIONS
Proper lug nut/bolt torque is very important to ensure that
the wheel is properly mounted to the vehicle. Any time a
wheel has been removed and reinstalled on the vehicle, the
lug nuts/bolts should be torqued using a properly cali-
brated torque wrench using a high quality six sided (hex)
deep wall socket.
Torque Specifications
Lug Nut/
Bolt Torque Lug Nut/
Bolt Type **Lug Nut/
Bolt Size Lug Nut/
Bolt Socket Size
120-150 Ft- Lbs (160-
200 N·m) Cone M14 x 1.50 22 mm
130-160 Ft- Lbs (190-
220 N·m) Flanged
**Use only your authorized dealer recommended lug nuts/
bolts and clean or remove any dirt or oil before tightening.
Inspect the wheel mounting surface prior to mounting the
tire and remove any corrosion or loose particles.
9
TECHNICAL SPECIFICATIONS 425