Normal Ride Height (NRH)– This is the standard position
of the suspension and is meant for normal driving. It will
automatically adjust to maintain the rear ride height as
conditions change.
Alternate Trailer Height (ATH) – Lowers the vehicle
approximately 1 in (25 mm) for a level truck, to be used as
required while trailer towing. It will automatically adjust
to maintain the rear ride height as conditions change.
Trailer Decoupling/Unloading - The air suspension sys-
tem will load level (lower/exhaust only) for up to 10 min-
utes after the vehicle is turned off. This allows for easy
removal of a trailer and/or load from the back of the truck
by maintaining the ride height. After 10 minutes you will
need to turn the ignition to the run position for the air
suspension to maintain ride height. If the air suspension
system is disabled using the settings menu (Tire Jack Mode,
Transport Mode or Alignment Mode) the system will
remain disabled when the vehicle is turned off. Reactivat-
ing the air suspension can be accomplished via the settings
menu or driving the vehicle above 5 mph (8 km/h) for Tire
Jack Mode or Alignment Mode and 16 mph (26 km/h) for
Transport Mode. NOTE:
•
Most 3500 models will not lower to Alternate Trailer
Height (ATH) when unloaded.
• Refer to “Trailer Towing” in “Starting And Operating”
for further information.
Ignition OFF Behavior
For a predetermined amount of time after the ignition is off
the air suspension may adjust to maintain a proper appear-
ance.
WARNING!
The air suspension system uses a high pressure vol-
ume of air to operate the system. To avoid personal
injury or damage to the system, see your authorized
dealer for service.
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Instrument Cluster Display Messages
When the appropriate conditions exist, a message will
appear in the instrument cluster display. Refer to “Instru-
ment Cluster Display” in “Understanding Your Instrument
Panel” for further information.
An audible chime will be heard whenever a system error
has been detected.
See your authorized dealer for system service if normal
operation does not resume.
Operation
Pushing the Alternate Trailer Height (ATH) button once
while at Normal Ride Height (NRH), will lower the vehicle
to Alternate Trailer Height (ATH) and will illuminate the
LED.
NOTE:The LED will continuously blink until vehicle
Alternate Trailer Height (ATH) has been achieved and the
LED will turn off.
Pushing the Alternate Trailer Height (ATH) again will raise
the vehicle to Normal Ride Height (NRH).
NOTE: The LED will continuously blink until Normal Ride
Height (NRH) has been achieved. •
Transport Mode – No indicator lamps will be illumi-
nated. Transport Mode is disabled by driving the ve-
hicle.
• Tire/Jack Mode – No indicator lamps will be illumi-
nated. Tire/Jack Mode is disabled by driving the vehicle.
• Wheel Alignment Mode – No indicator lamps will be
illuminated. Wheel Alignment Mode is disabled by
driving the vehicle.
AXLE LOCKER SYSTEM — POWER WAGON
MODELS ONLY (IF EQUIPPED)
This vehicle 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 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 not recommended to drive the vehicle with
the differentials locked on pavement due to the reduced
ability to turn and speed limitations.
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This system is controlled by the electronic control sway bar
switch located on the instrument panel.
The switch has two positions; On-Road and Off-Road. The
system is normally in the On-Road mode, indicated by a
solid green light. The stabilizer/sway bar should remain in
the On-Road mode during normal driving conditions.WARNING!
Do not disconnect the stabilizer bar and drive on hard
surfaced roads or at speeds above 18 mph (29 km/h),
you may lose control of the vehicle, which could result
in serious injury or death. The front stabilizer bar
enhances vehicle stability and assists in maintaining
control of the vehicle. The system monitors vehicle
speed and will attempt to reconnect the stabilizer bar
at speeds over 18 mph (29 km/h). This is indicated by a
flashing off road light and solid on road light. Once
vehicle speed is reduced below 14 mph (22 km/h), the
system will attempt to return to the Off-Road mode.
To disconnect the stabilizer/sway bar, shift to either 4HI or
4LO as shown in “Four Wheel Drive Operation” and push
the right hand Off Road stabilizer/sway bar button to
obtain the Off-Road position. The amber indicator light
will flash until the stabilizer/sway bar has been fully
disconnected.
Sway Bar Disconnect Buttons
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Ramp Travel Index (RTI)
The ramp travel index is the distance, in inches, that you
can drive your vehicle with one wheel on a 20-degree ramp
without lifting any other wheel off the ground. This
distance up the ramp divided by the wheelbase of the
vehicle and multiplied by 1,000 is the RTI. This vehicle has
an RTI of 510, which means you can articulate one front
wheel 26 inches (66 cm) in the air while the other three
wheels remain in contact with the ground.
Water Fording Characteristics
Water fording characteristic is the vehicle’s ability to cross
a body of still water, where the powertrain and drivetrain
are safe from water ingestion. This vehicle has high water
fording characteristics with the ability to cross a pool of
water, without stopping, 24 inches (60 cm) deep at a
maximum speed of 10 mph (16 km/h) and a pool of water
30 inches (76 cm) deep at a maximum speed of 5 mph
(8 km/h), both with an entrance ramp angle of 1.3 degrees.
CAUTION!
The door sill height is 25 inches (63.5 cm). Water may
intrude into the interior of the vehicle at greater
depths.
Simultaneous Brake And Throttle Operation
Many off-road driving conditions require the simultaneous
use of the brake and throttle (two footed driving). When
climbing rocks, logs, or other stepped objects, using light
brake pressure with light throttle will keep the vehicle from
jerking or lurching. This technique is also used when you
need to stop and restart a vehicle on a steep incline.
The Basics Of Off-Road Driving
You will encounter many types of terrain driving off-road.
You should be familiar with the terrain and area before
proceeding. There are many types of surface conditions: hard
packed dirt, gravel, rocks, grass, sand, mud, snow and ice.
Every surface has a different effect on your vehicle’s steering,
handling and traction. Controlling your vehicle is one of the
keys to successful off-road driving, so always keep a firm
grip on the steering wheel and maintain a good driving
posture. Avoid sudden accelerations, turns or braking. In
most cases there are no road signs, posted speed limits or
signal lights. Therefore you will need to use your own good
judgment on what is safe and what isn’t. When on a trail you
should always be looking ahead for surface obstacles and
changes in terrain. The key is to plan your future driving
route while remembering what you are currently driving
over.
458 STARTING AND OPERATING
CAUTION!
Never park your vehicle over dry grass or other com-
bustible materials. The heat from your vehicle exhaust
system could cause a fire.
WARNING!
Always wear your seat belt and firmly tie down cargo.
Unsecured cargo can become projectiles in an off-road
situation.
When To Use Low Range
When driving off-road, shift into 4LO (Low Range) for
additional traction or to improve handling and control on
slippery or difficult terrain. Due to the lower gearing, low
range will allow the engine to operate in a higher power
range. This will allow you to idle over obstacles and down
hills, with improved control and less effort. Also, use 4LO
(Low Range) in rain, ice, snow, mud, sand, to get heavy
loads rolling, improve traction, or whenever 4HI (High
Range) traction will not do the job.
Driving In Snow, Mud And Sand
There is a drastic reduction in traction when driving in
snow, mud or sand. The vehicle will be less responsive to
steering, acceleration and braking inputs. Therefore you
should accelerate slowly, leave greater stopping distances
and avoid abrupt vehicle maneuvers. You want to keep a
slow constant steady pace. The key is to maintain the
vehicle’s momentum.
•Snow – In heavy snow or for additional control and
traction at slower speeds, shift the transmission to a low
gear and shift the transfer case to 4LO (Low Range) if
necessary. Do not shift to a lower gear than necessary to
maintain headway. Over-revving the engine can spin the
wheels and traction will be lost. If you start to slow to a
stop, try turning your steering wheel no more than a ¼
turn quickly back and forth, while still applying throttle.
This will allow the tires to get a fresh biteand help
maintain your momentum.
CAUTION!
On icy or slippery roads, do not downshift at high
engine RPMs or vehicle speeds because engine brak-
ing may cause skidding and loss of control.
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STARTING AND OPERATING 459
•Mud – Deep mud creates a great deal of suction around
the tires and is very difficult to get through. You should
use 4LO (Low Range) with a gear low enough to
maintain your momentum without shifting. If you start
to slow to a stop, try turning your steering wheel no
more than a ¼ turn quickly back and forth for additional
traction. Mud holes pose an increased threat of vehicle
damage and getting stuck. They are normally full of
debris from previous vehicles getting stuck. As a good
practice before entering any mud hole, get out and
determine how deep it is, if there are any hidden
obstacles and if the vehicle can be safely recovered if
stuck.
• Sand – Soft sand is very difficult to travel through with
full tire pressure. When crossing soft sandy spots in a
trail maintain your vehicle’s momentum and do not
stop. The key to driving in soft sand using the appro-
priate tire pressure, accelerating slowly, avoiding abrupt
maneuvers and maintaining the vehicle’s momentum. If
you are going to be driving on large soft sandy areas or
dunes, reduce your tire pressure to a minimum of 15 psi
(103 kPa) to allow for a greater tire surface area. Reduced
tire pressure will drastically improve your traction and
handling, while driving on the soft sand, but you must
return the tires to normal air pressure before driving on pavement or other hard surfaces. Be sure you have a
way to air the tires back up prior to reducing the
pressure.
CAUTION!
Reduced tire pressures may cause tire unseating and
total loss of air pressure. To reduce the risk of tire
unseating, while at a reduced tire pressure, reduce your
speed and avoid sharp turns or abrupt maneuvers.
Crossing Obstacles (Rocks And Other High Points)
While driving off road, you will encounter many types of
terrain. These varying types of terrain bring different types
of obstacles. Before proceeding review the path ahead to
determine the correct approach and your ability to safely
recover the vehicle if something goes wrong. Keeping a
firm grip on the steering wheel, bring the vehicle to a
complete stop and then inch the vehicle forward until it
makes contact with the object. Apply the throttle lightly
while holding a light brake pressure and ease the vehicle
up and over the object.
460 STARTING AND OPERATING
WARNING!
Crossing obstacles can cause abrupt steering system
loading which could cause you to loose control of your
vehicle.
Using A Spotter
There are many times where it is hard to see the obstacle or
determine the correct path. Determining the correct path
can be extremely difficult when you are confronting many
obstacles. In these cases have someone guide you over,
through, or around the obstacle. Have the person stand a
safe distance in front of you where they can see the
obstacle, watch your tires and undercarriage, and guide
you through.
Crossing Large Rocks
When approaching large rocks, choose a path which en-
sures you drive over the largest with your tires. This will
lift your undercarriage over the obstacle. The tread of the
tire is tougher and thicker than the side wall and is
designed to take the abuse. Always look ahead and make
every effort to cross the large rocks with your tires.
CAUTION!
•Never attempt to straddle a rock that is large enough
to strike your axles or undercarriage.
• Never attempt to drive over a rock which is large
enough to contact the door sills.
Crossing A Ravine, Gully, Ditch, Washout Or Rut
When crossing a ravine, gully, ditch, washout or a large rut,
the angled approach is the key to maintaining your vehi-
cle’s mobility. Approach these obstacles at a 45-degree
angle and let each tire go through the obstacle indepen-
dently. You need to use caution when crossing large
obstacles with steep sides. Do not attempt to cross any
large obstacle with steep sides at an angle great enough to
put the vehicle at risk of a rollover. If you get caught in a
rut, dig a small trench to the right or left at a 45-degree
angle ahead of the front tires. Use the removed dirt to fill
the rut ahead of the turnout you just created. You should
now be able to drive out following the trench you just
created at a 45-degree angle.
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STARTING AND OPERATING 461
into a lower gear, shift the transfer case into 4LO (Low)
and proceed with caution. You should use first gear and
4LO (Low Range) for very steep hills.
• Driving Up Hill – Once you have determined your
ability to proceed and have shifted into the appropriate
gear, line your vehicle up for the straightest possible run.
Accelerate with an easy constant throttle and apply
more power as you start up the hill. Do not race forward
into a steep grade, the abrupt change of grade could
cause you to lose control. If the front end begins to
bounce, ease off the throttle slightly to bring all four tires
back on the ground. As you approach the crest of the hill
ease off the throttle and slowly proceed over the top. If
the wheels start to slip as you approach the crest of a hill,
ease off the accelerator and maintain headway by turn-
ing the steering wheel no more than a ¼ turn quickly
back and forth. This will provide a fresh biteinto the
surface and will usually provide enough traction to
complete the climb. If you do not make it to the top,
place the vehicle in REVERSE and back straight down
the grade using engine resistance along with the vehicle
brakes.WARNING!
Never attempt to climb a hill at an angle or turn around
on a steep grade. Driving across an incline increases
the risk of a roll over, which may result in severe injury
or death.
• Driving Down Hill – Before driving down a steep hill
you need to determine if it is too steep for a safe descent.
What is the surface traction? Is the grade too steep to
maintain a slow controlled descent? Are there obstacles?
Is it a straight descent? Is there plenty of distance at the
base of the hill to regain control if the vehicle descends
too fast? If you feel confident in your ability to proceed
then make sure you are in 4LO (Low Range) with the
transmission in first gear (manually select first gear on
automatic transmissions) and proceed with caution.
Allow engine braking to control the descent and apply
your brakes if necessary, but do not allow the tires to
lock.
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