•Vehicle speed is sufficiently high,
• The TOW/HAUL switch has not been activated, and
• The driver is not heavily pressing the accelerator.
When To Use TOW/HAUL Mode
When driving in hilly areas, towing a trailer, carrying a
heavy load, etc., and frequent transmission shifting occurs,
push the TOW/HAUL switch to activate TOW/HAUL
mode. This will improve performance and reduce the
potential for transmission overheating or failure due to
excessive shifting. When operating in TOW/HAUL mode,
transmission upshifts are delayed, and the transmission
will automatically downshift (for engine braking) when the
throttle is closed and/or during steady braking maneu-
vers. The “TOW/HAUL Indicator Light” will illuminate in the
instrument cluster to indicate that TOW/HAUL mode has
been activated. Pushing the switch a second time restores
normal operation. Normal operation is always the default
at engine start-up. If TOW/HAUL mode is desired, the
switch must be pushed each time the engine is started.
TOW/HAUL Switch
314 STARTING AND OPERATING
WARNING!
Do not coast in NEUTRAL and never turn off the
ignition to coast down a hill. These are unsafe practices
that limit your response to changing traffic or road
conditions. You might lose control of the vehicle and
have a collision.
CAUTION!
Towing the vehicle, coasting, or driving for any other
reason with the transmission in NEUTRAL can cause
severe transmission damage. Refer to “Recreational
Towing” in “Starting And Operating” and “Towing A
Disabled Vehicle” in “In Case Of Emergency” for
further information.
DRIVE (D)
This range should be used for most city and highway
driving. It provides the smoothest upshifts and downshifts,
and the best fuel economy. The transmission automatically
upshifts through underdrive first, second, and third gears,
direct fourth gear and overdrive fifth and sixth gears. The
DRIVE position provides optimum driving characteristics
under all normal operating conditions. When frequent transmission shifting occurs (such as when
operating the vehicle under heavy loading conditions, in
hilly terrain, traveling into strong head winds, or while
towing a heavy trailer), use the Electronic Range Select
(ERS) shift control (refer to “Electronic Range Select (ERS)
Operation” in this section for further information) to select
a lower gear range. Under these conditions, using a lower
gear range will improve performance and extend transmis-
sion life by reducing excessive shifting and heat buildup.
If the transmission temperature exceeds normal operating
limits, the powertrain controller will modify the transmis-
sion shift schedule and expand the range of torque con-
verter clutch engagement. This is done to prevent trans-
mission damage due to overheating.
If the transmission becomes extremely hot or is in danger
of overheating, the “Transmission Temperature Warning
Light” may illuminate and the transmission may operate
differently until the transmission cools down.
NOTE:
Use cautionwhen operating a heavily loaded ve-
hicle at low speeds (such as towing a trailer up a steep
grade, or in stop-and-go traffic) during hot weather. In
these conditions, torque converter slip can impose a sig-
nificant additional heat load on the cooling system. Down-
shifting the transmission to the lowest possible gear (when
6
STARTING AND OPERATING 319
NOTE:To select the proper gear position for maximum
deceleration (engine braking), simply push and hold the
ERS (-) switch. The transmission will shift to the range
from which the vehicle can best be slowed down.
CAUTION!
When using ERS for engine braking while descending
steep grades, be careful not to overspeed the engine.
Apply the brakes as needed to prevent engine over-
speed.
Overdrive Operation
The automatic transmission includes an electronically con-
trolled Overdrive (fifth and sixth gears). The transmission
will automatically shift into Overdrive if the following
conditions are present:
• The gear selector is in the DRIVE position.
• The transmission fluid has reached an adequate tem-
perature.
• The engine coolant has reached an adequate tempera-
ture. •
Vehicle speed is sufficiently high.
• The TOW/HAUL switch has not been activated.
• The driver is not heavily pressing the accelerator.
When To Use TOW/HAUL Mode
When driving in hilly areas, towing a trailer, carrying a
heavy load, etc., and frequent transmission shifting occurs,
push the TOW/HAUL switch to activate TOW/HAUL
mode. This will improve performance and reduce the
potential for transmission overheating or failure due to
excessive shifting. When operating in TOW/HAUL mode,
transmission upshifts are delayed, and the transmission
will automatically downshift (for engine braking) when the
throttle is closed and/or during steady braking maneu-
vers.
322 STARTING AND OPERATING
Protection Strategy
In order to “protect” the air suspension system, the vehicle
will disable load leveling as required (suspension over-
loaded, battery charge low, etc.). Load leveling will auto-
matically resume as soon as system operation requirements
are met. See your authorized dealer if system does not
resume.
NOTE:If towing with air suspension refer to “Trailer
Towing” in “Starting And Operating” for further informa-
tion.
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 “Getting To Know Your Instru-
ment 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
1 — Up Button
2 — Down Button
3 — Entry/Exit Mode Indicator (Customer selectable)
4 — Normal Ride Height Indicator (Customer selectable)
5 — Off-Road 1 Indicator (Customer selectable)
6 — Off-Road 2 Indicator (Customer selectable)
The indicator lamps 3 through 6 will illuminate to show the
current position of the vehicle. Flashing indicator lamps
will show a position which the system is working to
achieve. When raising, if multiple indicator lamps are
Air Suspension Switch
348 STARTING AND OPERATING
Protection Strategy
In order to “protect” the air suspension system, the vehicle
will disable load leveling as required (suspension over-
loaded, battery charge low, etc.). Load leveling will auto-
matically resume as soon as system operation requirements
are met. See your authorized dealer if system does not
resume.
NOTE:If towing with air suspension refer to “Trailer
Towing” in “Starting And Operating” for further informa-
tion.
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 “Getting To Know Your Instru-
ment 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
The indicator lamps 3 through 6 will illuminate to show the
current position of the vehicle. Flashing indicator lamps
will show a position which the system is working to
achieve. When raising or lowering, the flashing indicator
lamp is the position the system is working to achieve.
Air Suspension Switch
1 — Up Button
2 — Down Button
3 — Entry/Exit Mode Indicator Lamp (Customer selectable)
4 — Aero Mode Indicator Lamp (Customer selectable)
5 — Normal Ride Height Indicator Lamp (Customer selectable)
6 — Off-Road Indicator Lamp (Customer selectable)
354 STARTING AND OPERATING
AIR SUSPENSION SYSTEM (2500/3500 MODELS) —
IF EQUIPPED
Description
This air suspension system is a rear leveling ride height
system. The main purpose of this system is to maintain the
truck’s rear ride height level. There are two selectable
heights that can be chosen based on your operating condi-
tions.
The system requires that the ignition be in ON/RUN
position or the engine running with zero vehicle speed for
all user requested changes and load leveling.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
minutes 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.
Rear Leveling Ride Height Switch
356 STARTING AND OPERATING
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.
Air Suspension Modes
The air suspension system has multiple modes to protect
the system in unique situations:
Tire/Jack Mode
To assist with changing a tire, the air suspension system
has a feature which allows the automatic leveling to be disabled. This mode is intended to be enabled with engine
running. Refer to “Instrument Cluster Display” in “Getting
To Know Your Instrument Panel” or “Uconnect Settings” in
“Multimedia” if equipped with a touch screen radio for
further information.
NOTE:
This mode is intended to be enabled with engine
running.
Transport Mode
For towing your vehicle with four wheels off the road, the
air suspension system has a feature which will put the
vehicle below Normal Ride Height (NRH) and disable the
automatic load leveling system. This mode is intended to
be enabled with engine running. Refer to “Instrument
Cluster Display” in “Getting To Know Your Instrument
Panel” or “Uconnect Settings” in “Understanding Your
Instrument Panel” if equipped with a touch screen radio
for further information.
NOTE: This mode is intended to be enabled with engine
running.
Wheel Alignment Mode
Before performing a wheel alignment this mode must be
enabled. Refer to “Instrument Cluster Display” in “Getting
6
STARTING AND OPERATING 357
To Know Your Instrument Panel” or “Uconnect Settings” in
“Multimedia” if equipped with a touch screen radio for
further information.
NOTE:This mode is intended to be enabled with engine
running.
Protection Strategy
In order to “protect” the air suspension system, the vehicle
will disable load leveling as required (suspension over-
loaded, battery charge low, etc.). Load leveling will auto-
matically resume as soon as system operation requirements
are met. See your authorized dealer if system does not
resume.
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 “Getting To Know Your Instru-
ment 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.
358 STARTING AND OPERATING