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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 commer-
cial scale to insure that the GVWR has not been exceeded.
580 STARTING AND OPERATING
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WARNING!(Continued)
3. GAWR
4. Tongue weight rating for the trailer hitch utilized.
Towing Requirements — Tires
•Do not attempt to tow a trailer while using a compact
spare tire.
• Proper tire inflation pressures are essential to the safe
and satisfactory operation of your vehicle. Refer to
“Tires – General Information” in “Starting and Oper-
ating” for proper tire inflation procedures.
• Check the trailer tires for proper tire inflation pres-
sures before trailer usage.
• Check for signs of tire wear or visible tire damage
before towing a trailer. Refer to “Tires – General
Information” in “Starting and Operating” for the
proper inspection procedure. •
When replacing tires, refer to “Tires – General Infor-
mation” in “Starting and Operating” for proper tire
replacement procedures. Replacing tires with a higher
load carrying capacity will not increase the vehicle’s
GVWR and GAWR limits.Towing Requirements — Trailer Brakes
WARNING!
•Do not connect trailer brakes to your vehicle’s hy-
draulic brake lines. It can overload your brake system
and cause it to fail. You might not have brakes when
you need them and could have an accident.
•Towing any trailer will increase your stopping dis-
tance. When towing you should allow for additional
space between your vehicle and the vehicle in front
of you. Failure to do so could result in an accident.
592 STARTING AND OPERATING
Page 620 of 790

supplement to the radiator and aids in removing heat
from the engine cooling system.
CAUTION!
Driving with a hot cooling system could damage
your vehicle. If the temperature gauge reads HOT
(H), pull over and stop the vehicle. Idle the vehicle
with the air conditioner turned off until the pointer
drops back into the normal range. If the pointer
remains on HOT (H), and you hear continuous
chimes, turn the engine off immediately and call for
service.
WARNING!
You or others can be badly burned by hot engine
coolant (antifreeze) or steam from your radiator. If
you see or hear steam coming from under the hood,
do not open the hood until the radiator has had time
to cool. Never try to open a cooling system pressure
cap when the radiator or coolant bottle is hot.
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 calibrated torque wrench.
618 WHAT TO DO IN EMERGENCIES
Page 635 of 790

end of the wheel nuts toward the wheel. To avoid the
risk of forcing the vehicle off the jack, do not fully
tighten the wheel nuts until the vehicle has been
lowered.
6. Finish tightening the lug nuts. Push down on the wrench while at the end of the handle for increased
leverage. Tighten the lug nuts in a star pattern until
each nut has been tightened twice. For the correct lug
nut torque refer to “Torque Specifications” in this
section. If in doubt about the correct tightness, have
them checked with a torque wrench by you authorized
dealer or service station.
WARNING!
A loose tire or jack thrown forward in a collision or
hard stop could injure someone in the vehicle. Al-
ways stow the jack parts and the extra tire and wheel
in the places provided. 7. Install the wheel center cap and remove the wheel
blocks. Do not install chrome or aluminum wheel
center caps on the spare wheel. This may result in cap
damage.
8. Lower the jack to its fully closed position. If the bottle jack will not lower by turning the dial (thumbwheel)
by hand, it may be necessary to use the jack drive tube
in order to lower the jack. Stow the replaced tire, jack,
and tools as previously described.
9. Adjust the tire pressure when possible.
NOTE: Do not oil wheel studs. For chrome wheels, do
not substitute with chrome plated wheel nuts.
6
WHAT TO DO IN EMERGENCIES 633
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them checked with a torque wrench by you authorized
dealer or service station.
WARNING!
A loose tire or jack thrown forward in a collision or
hard stop could injure someone in the vehicle. Al-
ways stow the jack parts and the extra tire and wheel
in the places provided.
7. Install the wheel center cap and remove the wheel blocks. Do not install chrome or aluminum wheel
center caps on the spare wheel. This may result in cap
damage.
8. Lower the jack to its fully closed position. If the bottle jack will not lower by turning the dial (thumbwheel)
by hand, it may be necessary to use the jack drive tube
in order to lower the jack. Stow the replaced tire, jack,
and tools as previously described. 9. Adjust the tire pressure when possible.
NOTE:
Do not oil wheel studs. For chrome wheels, do
not substitute with chrome plated wheel nuts.To Stow The Flat Or Spare
NOTE: Have the flat tire repaired or replaced immedi-
ately.
WARNING!
A loose tire thrown forward in a collision or hard
stop could injure the occupants in the vehicle. Have
the deflated (flat) tire repaired or replaced immedi-
ately.
1. Turn the wheel so that the valve stem is facing the ground and toward the rear of the vehicle for conve-
nience in checking the spare tire inflation. Slide the
wheel retainer through the center of the wheel.
6
WHAT TO DO IN EMERGENCIES 653
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Cooling System
WARNING!
You or others can be badly burned by hot engine
coolant (antifreeze) or steam from your radiator. If
you see or hear steam coming from under the hood,
do not open the hood until the radiator has had time
to cool. Never try to open a cooling system pressure
cap when the radiator is hot.
Engine Coolant Checks
Check the engine coolant (antifreeze) protection every 12
months (before the onset of freezing weather, where
applicable). If the engine coolant (antifreeze) is dirty or
rusty in appearance, the system should be drained,
flushed and refilled with fresh coolant. Check the front of
the A/C condenser (if equipped) or radiator for any
accumulation of bugs, leaves, etc. If dirty, clean by gentlyspraying water from a garden hose vertically down the
face of the A/C condenser (if equipped) or the back of the
radiator core.
Check the engine cooling system hoses for brittle rubber,
cracking, tears, cuts and tightness of the connection at the
coolant recovery bottle and radiator. Inspect the entire
system for leaks.
With the engine at normal operating temperature (but
not running), check the cooling system pressure cap for
proper vacuum sealing by draining a small amount of
engine coolant (antifreeze) from the radiator drain cock.
The radiator drain cock is located in the lower radiator
tank. If the cap is sealing properly, the engine coolant
(antifreeze) will begin to drain from the coolant expan-
sion bottle. DO NOT REMOVE THE COOLANT PRES-
SURE CAP WHEN THE COOLING SYSTEM IS HOT.
7
MAINTAINING YOUR VEHICLE 697
Page 726 of 790
Cavity Cartridge Fuse Micro FuseDescription
F33 20 Amp Yellow Cummins Diesel Fuel Heater #1 – If Equipped / Rear
Blower – If Equipped
F34 30 Amp Pink Vehicle System Interface Module #2 – If Equipped
F35 30 Amp Pink Sunroof – If Equipped
F36 30 Amp Pink Rear Defroster– If Equipped
F37 30 Amp Pink Cummins Diesel Fuel Heater #2 If Equipped
F38 30 Amp Pink Power Inverter 115V AC– If Equipped
F39 30 Amp Pink Vehicle System Interface Module #1– If Equipped
F41 10 Amp Red Active Grill Shutter
F42 20 Amp Yellow Horn
F43 10 Amp RedSnow Plow (Left) – If Equipped
F44 10 Amp Red Diagnostic Port
F46 10 Amp RedTire Pressure Monitor
F47 10 Amp RedSnow Plow (Right) – If Equipped
F49 10 Amp RedInstrument Panel Cluster
724 MAINTAINING YOUR VEHICLE
Page 753 of 790
Severe Duty All Models
•Change Engine Oil at 4000 miles (6,500 km) if the
vehicle is operated in a dusty and off road environ-
ment. This type of vehicle use is considered Severe
Duty
Once A Month Or Before A Long Trip:
• Check engine oil level
• Check windshield washer fluid level •
Check tire pressure and look for unusual wear or dam-
age. Rotate tires at the first sign of irregular wear, even if
it occurs before the oil indicator system turns on.
• Check the fluid levels of the coolant reservoir, brake
master cylinder, power steering (2500/3500 Models
Only) and automatic transmission (six-speed only) as
needed
• Check function of all interior and exterior lights
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SMAINTENANCE SCHEDULES 751