When parking on a hill, it is important to turn the front
wheels toward the curb on a downhill grade and away
from the curb on an uphill grade. Apply the parking brake
before placing the gear selector in PARK, otherwise the
load on the transmission locking mechanism may make it
difficult to move the gear selector out of PARK. The
parking brake should always be applied whenever the
driver is not in the vehicle.
WARNING!
•Never use the PARK position as a substitute for the
parking brake. Always apply the parking brake fully
when parked to guard against vehicle movement and
possible injury or damage.
• Never leave children alone in a vehicle, or with
access to an unlocked vehicle. Leaving unattended
children in a vehicle is dangerous for a number of
reasons. A child or others could be seriously or
fatally injured.
• Do not leave the key fob in or near the vehicle, or in
a location accessible to children, and do not leave a
vehicle equipped with Keyless Enter-N-Go in the
ACC or ON/RUN mode. A child could operate power
windows, other controls, or move the vehicle.
(Continued)
WARNING! (Continued)
•Be sure the parking brake is fully disengaged before
driving; failure to do so can lead to brake failure and
a collision.
• Always fully apply the parking brake when leaving
your vehicle or it may roll and cause damage or
injury. Also, be certain to leave the transmission in
PARK. Failure to do so may cause the vehicle to roll
and cause damage or injury.
CAUTION!
If the Brake System Warning Light remains on with the
parking brake released, a brake system malfunction is
indicated. Have the brake system serviced by an au-
thorized dealer immediately.
244 STARTING AND OPERATING
Six–Speed Automatic Transmission — If Equipped
Chassis Cab models (with automatic transmission) may
use either the AS66RC transmission (which is equipped
with a Power Take-Off (PTO) access cover on the side of the
transmission case), or the 66RFE transmission (which has
no PTO access cover).
The transmission gear position display (located in the
instrument cluster) indicates the transmission gear range.
The gear selector is mounted on the right side of the
steering column. You must press the brake pedal to move
the gear selector out of PARK (refer to “Brake/
Transmission Shift Interlock System” in this section). To
drive, move the gear selector from PARK or NEUTRAL to
the DRIVE position. Pull the gear selector toward you
when shifting into REVERSE or PARK, or when shifting
out of PARK.
The electronically-controlled transmission provides a pre-
cise shift schedule. The transmission electronics are self-
calibrating; therefore, the first few shifts on a new vehicle
may be somewhat abrupt. This is a normal condition, and
precision shifts will develop within a few hundred miles
(kilometers).Only shift from DRIVE to PARK or REVERSE when the
accelerator pedal is released and the vehicle is stopped. Be
sure to keep your foot on the brake pedal when shifting
between these gears.
The transmission gear selector has only PARK, REVERSE,
NEUTRAL, and DRIVE shift positions. Manual downshifts
can be made using the Electronic Range Select (ERS) shift
control. Pushing the ERS (-/+) switches (on the gear
selector) while in the DRIVE position will select the highest
available transmission gear, and will display that gear limit
in the instrument cluster as 1, 2, 3, etc. Refer to
Electronic
Range Select (ERS) Operation in this section for further
information. Some models will display both the selected
gear limit, and the actual current gear, while in ERS mode.
Gear Ranges
Do not depress the accelerator pedal when shifting from
PARK or NEUTRAL into another gear range.
NOTE: After selecting any gear range, wait a moment to
allow the selected gear to engage before accelerating. This
is especially important when the engine is cold.
6
STARTING AND OPERATING 247
PARK (P)
This range supplements the parking brake by locking the
transmission. The engine can be started in this range.
Never attempt to use PARK while the vehicle is in motion.
Apply the parking brake when exiting the vehicle in this
range.
When parking on a level surface, you may shift the
transmission into PARK first, and then apply the parking
brake.
When parking on a hill, apply the parking brake before
shifting the transmission to PARK, otherwise the load on
the transmission locking mechanism may make it difficult
to move the gear selector out of PARK. As an added
precaution, turn the front wheels toward the curb on a
downhill grade and away from the curb on an uphill grade.
NOTE:On four-wheel drive vehicles be sure that the
transfer case is in a drive position.
When exiting the vehicle, always:
• Apply the parking brake.
• Shift the transmission into PARK.
• Turn the engine OFF.
• Remove the key fob.WARNING!
•Never use the PARK position as a substitute for the
parking brake. Always apply the parking brake fully
when exiting the vehicle to guard against vehicle
movement and possible injury or damage.
• Your vehicle could move and injure you and others if
it is not in PARK. Check by trying to move the gear
selector out of PARK with the brake pedal released.
Make sure the transmission is in PARK before exit-
ing the vehicle.
• It is dangerous to shift out of PARK or NEUTRAL if
the engine speed is higher than idle speed. If your
foot is not firmly pressing the brake pedal, the
vehicle could accelerate quickly forward or in re-
verse. You could lose control of the vehicle and hit
someone or something. Only shift into gear when the
engine is idling normally and your foot is firmly
pressing the brake pedal.
• Unintended movement of a vehicle could injure
those in or near the vehicle. As with all vehicles, you
should never exit a vehicle while the engine is
running. Before exiting a vehicle, always come to a
complete stop, then apply the parking brake, shift
(Continued)
248 STARTING AND OPERATING
WARNING!(Continued)
the transmission into PARK, turn the engine OFF,
and remove the key fob. When the ignition is in the
LOCK/OFF (key removal) position (or, with Keyless
Enter-N-Go, when the ignition is in the OFF mode),
the transmission is locked in PARK, securing the
vehicle against unwanted movement.
• When leaving the vehicle, always make sure the
ignition is in the OFF mode, remove the key fob from
the vehicle, and lock the vehicle.
• Never leave children alone in a vehicle, or with
access to an unlocked vehicle. Allowing children to
be in a vehicle unattended is dangerous for a number
of reasons. A child or others could be seriously or
fatally injured. Children should be warned not to
touch the parking brake, brake pedal or the trans-
mission gear selector.
• Do not leave the key fob in or near the vehicle (or in
a location accessible to children), and do not leave
the ignition (in a vehicle equipped with Keyless
Enter-N-Go) in the ACC or ON/RUN mode. A child
could operate power windows, other controls, or
move the vehicle.
CAUTION!
• Before moving the transmission gear selector out of
PARK, you must turn the ignition to the ON/RUN
mode, and also press the brake pedal. Otherwise,
damage to the gear selector could result.
• DO NOT race the engine when shifting from PARK
or NEUTRAL into another gear range, as this can
damage the drivetrain.
The following indicators should be used to ensure that you
have properly engaged the transmission into the PARK
position:
• When shifting into PARK, pull the gear selector toward
you and move it all the way counterclockwise until it
stops.
• Release the gear selector and make sure it is fully seated
in the PARK gate.
• Look at the transmission gear position display and
verify that it indicates the PARK position (P).
• With brake pedal released, verify that the gear selector
will not move out of PARK.
6
STARTING AND OPERATING 249
REVERSE (R)
This range is for moving the vehicle backward. Shift into
REVERSE only after the vehicle has come to a complete
stop.
NEUTRAL (N)
Use this range when the vehicle is standing for prolonged
periods with the engine running. The engine may be
started in this range. Apply the parking brake and shift the
transmission into PARK if you must exit the vehicle.
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
(Continued)
CAUTION!(Continued)
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.
250 STARTING AND OPERATING
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 caution when operating a heavily loaded vehicle
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 significant additional heat
load on the cooling system. Downshifting the transmission to
the lowest possible gear (when climbing a grade), or shifting
to NEUTRAL (when stopped in heavy traffic) can help to
reduce this excess heat generation.
During cold temperatures, transmission operation may be
modified depending on engine and transmission tempera-
ture as well as vehicle speed. This feature improves warm up
time of the engine and transmission to achieve maximum
efficiency. Engagement of the torque converter clutch is
inhibited until the transmission fluid is warm (refer to the
“Note” under “Torque Converter Clutch” in this section).
On models with 66RFE transmission, top overdrive gear is
also inhibited until the transmission fluid is warm, and
during extremely cold temperatures (-16°F [-27°C] or be-
low), operation may briefly be limited to first and direct
gears only. On trucks with AS66RC transmission, fifth and
sixth gears may be inhibited briefly on cold starts below
41°F (5°C), and during very cold temperatures (-4°F [-20°C]
or below), operation may briefly be limited to third gear
only. During this condition, the ability of the vehicle to
accelerate under heavily loaded conditions may be re-
duced. In all cases, normal operation will resume once the
transmission temperature has risen to a suitable level.
Transmission Limp Home Mode
Transmission function is monitored electronically for ab-
normal conditions. If a condition is detected that could
result in transmission damage, Transmission Limp Home
Mode is activated. In this mode, the transmission remains
in fourth gear (for 66RFE transmission) or third gear (for
AS66RC transmission) regardless of which forward gear is
selected. If an AS66RC equipped truck enters Limp Home
Mode at highway speeds, it will initially engage fifth gear,
until the vehicle slows to a speed where third gear can be
engaged. PARK, REVERSE, and NEUTRAL will continue
to operate. The Malfunction Indicator Light (MIL) may be
6
STARTING AND OPERATING 251
To exit ERS mode, simply push and hold the ERS (+) switch
until the gear limit display disappears from the instrument
cluster.
WARNING!
Do not downshift for additional engine braking on a
slippery surface. The drive wheels could lose their grip
and the vehicle could skid, causing a collision or
personal injury.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 overspeed.
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 temperature.
• Vehicle speed is sufficiently high.
• The TOW/HAUL switch has not been activated.
• The driver is not heavily pressing the accelerator.
Column Gear Selector
6
STARTING AND OPERATING 253
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.
WARNING!
Do not use the “TOW/HAUL” feature when driving in
icy or slippery conditions. The increased engine brak-
ing can cause the rear wheels to slide, and the vehicle
to swing around with the possible loss of vehicle
control, which may cause an accident possibly result-
ing in personal injury or death.
Torque Converter Clutch
A feature designed to improve fuel economy has been
included in the automatic transmission on your vehicle. A
clutch within the torque converter engages automatically
at calibrated speeds. This may result in a slightly different
feeling or response during normal operation in the upper
gears. When the vehicle speed drops or during some
accelerations, the clutch automatically disengages.
TOW/HAUL Switch
254 STARTING AND OPERATING