wheel size DODGE RAM 2500 POWER WAGON 2008 3.G Owners Manual

collision requiring the airbags, it signals the inflator
units. A large quantity of nontoxic gas is generated to
inflate the front airbags. Different airbag inflation rates
may be possible based on collision severity and occu-
pant size. The steering wheel hub trim cover and the
upper right side of the instrument panel separate and
fold out of the way as the bags inflate to their full size.
The bags fully inflate in about 50 - 70 milliseconds.
This is about half of the time it takes to blink your eyes.
The bags then quickly deflate while helping to restrain
the driver and front passenger. The driver's front
airbag gas is vented through vent holes in the sides of
the airbag. The passenger's front airbag gas is vented
through vent holes in the sides of the airbag. In this
way the airbags do not interfere with your control of
the vehicle.
²TheSide Impact SRS Window Bagsare designed to
activate only in certain side collisions. When the ORC
(with side impact option) detects a collision requiringthe window bags to inflate, it signals the inflators on
the crash side of the vehicle. A quantity of nontoxic gas
is generated to inflate the window bag. The inflating
window bag pushes the outside edge of the headliner
out of the way and covers the window. The airbag
inflates in about 30 milliseconds (about one quarter of
the time it takes to blink your eyes) with enough force
to injure you if you are not belted and seated properly,
or if items are positioned in the area where the
window bag inflates. This especially applies to chil-
dren. The window bag is only about 3-1/2 inches (9
cm) thick when it is inflated.
NOTE:At no time should any supplemental restraint
system (SRS) component or SRS related component or
fastener be modified or replaced with any part except
those which are approved by DaimlerChrysler/Mopar.
54 THINGS TO KNOW BEFORE STARTING YOUR VEHICLE

POWER WAGON FEATURES
Locking Front and Rear Differentials
Most 4WD trucks are equipped with open differentials
front and rear. This design is used because it allows each
wheel to turn independently helping to eliminate bind-
ing when cornering. A disadvantage of using an open
differential is when one or more wheels lose traction; all
of the power is directed to those wheels resulting in a loss
of momentum. The Power Wagon is equipped with
electronically locking front and rear differentials. These
differentials, when engaged, mechanically lock together
the axle shafts forcing the wheels to spin at an equal rate.
This allows the vehicle to maintain its momentum and
thus prevents it from becoming stuck. The locking front
and rear differentials should only be engaged during
low-speed, extreme off-road situations where one wheel
is likely to not be in contact with the ground. It is notrecommended to drive the vehicle with the differentials
locked on pavement due to the reduced ability to turn
and speed limitations.
4.56:1 Gears
This is the highest axle ratio available in a full-size
pickup. The high gearing helps to compensate for the
increased rolling mass and increase diameter of the
off-road tires. As well, there are many advantages to a
higher axle ratio in off-road applications. When driving
downhill the high gearing enables the driver to use the
engine to slow the vehicle down in a more controlled
manner. When driving up a steep grade, the ratio helps
by keeping the truck in its power band helping to
maintain upward momentum.
84 UNDERSTANDING THE FEATURES OF YOUR VEHICLE

When the malfunction indicator is illuminated, the sys-
tem may not be able to detect or signal low tire pressure
as intended. TPMS malfunctions may occur for a variety
of reasons, including the installation of replacement or
alternate tires or wheels on the vehicle that prevent the
TPMS from functioning properly. Always check the
TPMS malfunction telltale after replacing one or more
tires or wheels on your vehicle to ensure that the replace-
ment or alternate tires and wheels allow the TPMS to
continue to function properly.CAUTION!
The TPMS has been optimized for the original
equipment tires and wheels. TPMS pressures and
warning have been established for the tire size
equipped on your vehicle. Undesirable system opera-
tion or sensor damage may result when using re-
placement equipment that is not of the same size,
type, and/or style. Aftermarket wheels can cause
sensor damage. Do not use tire sealant from a can, or
balance beads if your vehicle is equipped with a
TPMS, as damage to the sensors may result.
188 UNDERSTANDING YOUR INSTRUMENT PANEL

FOUR-WHEEL- DRIVE OPERATION
Manually Shifted Transfer Case Operating
Information/Precautions
The transfer case provides 4 mode positions-2(rear)-
wheel-drive high range, 4-wheel-drive high range, neu-
tral, and 4-wheel-drive low range.
This transfer case is intended to be driven in the 2-wheel-
drive position (2H) for normal street and highway con-
ditions such as dry hard surfaced roads.
When additional traction is required the transfer case 4H
and 4L positions can be used to lock the front and rear
driveshafts together and force the front and rear wheels
to rotate at the same speed. This is accomplished by
simply moving the shift lever to the desired positions.
The 4H and 4L positions are intended for loose, slippery
road surfaces only. Driving in the 4H and 4L positions on
dry hard surfaced roads may cause increased tire wear
and damage to the driveline components.The 4-wheel drive high (4LOCK) and 4±wheel drive low
(4LOW) lights, located in the instrument cluster, alert the
driver that the vehicle is either in 4-wheel drive high or
4±wheel drive low and that the front and rear driveshafts
are locked together. There are no lights for the 2H or N
(Neutral) positions.
When operating your vehicle in 4L, the engine speed is
approximately three times that of the 2H or 4H positions
at a given road speed. Take care not to overspeed the
engine and do not exceed 25 mph (40 km/h).
Proper operation of 4-wheel-drive vehicles depends on
tires of equal size, type and circumference on each wheel.
Any difference will adversely affect shifting and can
cause damage to the transfer case.
NOTE:Do not attempt to make a shift while only the
front or rear wheels are spinning. The transfer case is not
equipped with a synchronizer and therefore the front and
rear driveshaft speeds must be equal for the shift to take
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WARNING!
²Do not use a tire, wheel size or rating other than that
specified for your vehicle. Some combinations of
unapproved tires and wheels may change suspension
dimensions and performance characteristics, result-
ing in changes to steering, handling, and braking of
your vehicle. This can cause unpredictable handling
and stress to steering and suspension components.
You could lose control and have an accident resulting
in serious injury or death. Use only the tire and wheel
sizes with load ratings approved for your vehicle.
²Never 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 an accident.
²Failure 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
readings.
Alignment And Balance
Poor suspension alignment may result in:
²Fast tire wear.
²Uneven tire wear, such as feathering and one-sided
wear.
²Vehicle pull to right or left.
Tires may also cause the vehicle to pull to the left or right.
Alignment will not correct this condition. See your dealer
for proper diagnosis.
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Improper alignment will not cause vehicle vibration.
Vibration may be a result of tire and wheel out-of-
balance. Proper balancing will reduce vibration and
avoid tire cupping and spotty wear.
SUPPLEMENTAL TIRE PRESSURE INFORMATION
Ð IF EQUIPPED
A light load vehicle condition is defined as two passen-
gers {150 lbs (68 kg) each} plus 200 lbs (91kg) of cargo.
Cold tire inflation pressures for a lightly loaded vehicle
will be found on the face of the driver's door.
TIRE CHAINS
Use ªClass Uº chains on Power Wagon models, or other
traction aids that meet SAE Type ªUº specifications.
NOTE:Chains must be the proper size for the vehicle,
as recommended by the chain manufacturer.
CAUTION!
To avoid damage to your vehicle, tires or chains, observe the
following precautions:
²Because of limited chain clearance between tires and other suspen-
sion components, it is important that only chains in good condition
are used. Broken chains can cause serious vehicle damage. Stop the
vehicle immediately if noise occurs that could suggest chain
breakage. Remove the damaged parts of the chain before further
use.
²Install chains as tightly as possible and then retighten after driving
about 1/2 mile (0.8 km).
²Do not exceed 45 mph (72 km/h).
²Drive cautiously and avoid severe turns and large bumps, espe-
cially with a loaded vehicle.
²Do not install tire chains on front wheels of 4x2 vehicles.
²Do not drive for a prolonged period on dry pavement.
²Observe the tire chain manufacturer's instructions on method of
installation, operating speed, and conditions for usage. Always use
the lower suggested operating speed of the chain manufacturer if
different than the speed recommended by the manufacturer.
344 STARTING AND OPERATING

These cautions apply to all chain traction devices, includ-
ing link and cable (radial) chains.
NOTE:On 4x4 Power Wagon models, class ªUº snow
chains are permitted on the rear wheels only of vehicles
equipped with LT285/70R17D.
CAUTION!
Do not use tire chains on the 4X4 front wheels of Ram
Trucks equipped with LT285/70R17D. There may not
be adequate clearance for the chains and you are
risking structural or body damage to your vehicle.
SNOW TIRES
Snow tires should be of the same size and type construc-
tion as the front tires. Consult the manufacturer of the
snow tire to determine any maximum vehicle speed
requirement associated with the tire. These tires should
always be operated at the vehicle maximum capacity
inflation pressures under any load condition.
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 pro-
hibit studded tires; therefore, local laws should be
checked before using these tire types.
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The TPM System will continue to warn the driver of low
tire pressure as long as the condition exists, and will not
turn off until the tire pressure is at or above recom-
mended cold placard pressure. Once the low tire pressure
warning has been illuminated, the tire pressure must be
increased to the recommended cold placard pressure in
order for the TPMS warning lamp to be turned off. The
system will automatically update and the TPMS warning
lamp will extinguish once the updated tire pressures
have been received. The vehicle may need to be driven
for up to 10 minutes above 15 mph (25 km/h) to receive
this information.
As an example, assume your vehicle has a recommended
cold tire inflation placard pressure (parked for more than
3 hours) of 35 psi (241 kPa). If the ambient temperature is
68_F (20_C) and the measured tire pressure is 30 psi (207
kPa), a temperature drop to 20_F (-7_C) will decrease the
tire pressure to approximately 26 psi (179 kPa). This tire
pressure is sufficiently low enough to turn ON the TirePressure Monitoring lamp. Driving the vehicle may cause
the tire pressure to rise to approximately 30 psi (207 kPa),
but the Tire Pressure Monitoring lamp will still be ON. In
this situation, the Tire Pressure Monitoring lamp will
turn OFF only after the tires have been inflated to the
vehicle's recommended cold tire placard pressure value.
CAUTION!
The TPMS has been optimized for the original
equipment tires and wheels. TPMS pressures have
been established for the tire size equipped on your
vehicle. Undesirable system operation or sensor
damage may result when using replacement equip-
ment that is not of the same size, type, and/or style.
After-market wheels can cause sensor damage. Do
not use aftermarket tire sealants or balance beads if
your vehicle is equipped with a TPMS, as damage to
the sensors may result.
348 STARTING AND OPERATING

the ignition key is cycled, this sequence will repeat,
providing the system fault still exists. A system fault can
occur by any of the following scenarios:
1. Signal interference due to electronic devices or driving
next to facilities emitting the same Radio Frequencies as
the TPM sensors.
2. Installing aftermarket window tinting that affects ra-
dio wave signals.
3. Accumulation of snow or ice around the wheels or
wheel housings.
4. Using tire chains on the vehicle.
5. Using wheels/tires not equipped with TPM sensors.
6. Loss of communication with the trigger modules or
tire pressure monitoring sensors.
NOTE: Your vehicle is equipped with a non-matching
full size spare wheel and tire assembly.1. This spare tire does not have a tire pressure monitor-
ing sensor. Therefore, the TPMS will not monitor the tire
pressure in the spare tire.
2. If you install the full size spare tire in place of a road
tire that has a pressure below the low-pressure warning
limit, upon the next ignition key cycle, a chime will
sound and the TPM Telltale Light will still turn ON due
to the low tire.
3. However, after driving the vehicle for up to 10 min-
utes above 15 mph (25 km/h), the TPM Telltale Light will
flash on and off for 75 seconds and then remain on solid.
4. For each subsequent ignition key cycle, a chime will
sound and the TPM Telltale Light will flash on and off for
75 seconds and then remain on solid.
5. Once you repair or replace the original road tire, and
reinstall it on the vehicle in place of the full size spare tire,
the TPMS will update automatically and the TPM Telltale
356 STARTING AND OPERATING

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 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.
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 front and rear axle. Weighing
the vehicle may show that the GAWR of either the front
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