LOCK/OFF position, and the transmission is locked in
PARK whenever the ignition switch is in the LOCK/OFF
position.
NOTE: If a malfunction occurs, the system will trap the
Key Fob in the ignition switch to warn you that this
safety feature is inoperable. The engine can be started
and stopped but the Key Fob cannot be removed until
you obtain service.
Brake/Transmission Shift Interlock System
This vehicle is equipped with a Brake Transmission Shift
Interlock system (BTSI) that holds the gear selector in
PARK unless the brakes are applied. To shift the trans-
mission out of PARK, the ignition must be turned to the
ON/RUN position (engine running or not) and the brake
pedal must be pressed. 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.408 STARTING AND OPERATING
The electronically-controlled transmission provides a
precise 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, RE-
VERSE, NEUTRAL, and DRIVE shift positions. Manual
downshifts can be made using the Electronic Range
Select (ERS) shift control (refer to “Electronic Range
Select [ERS] Operation” in this section for further infor-
mation). 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. Models with the Driver Information Display (DID) will display
both the selected gear limit, and the actual current gear,
while in ERS mode.
Gear Ranges
DO NOT race the engine 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.
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 leaving the
vehicle in this range. 5STARTING AND OPERATING 409
CAUTION!• Before moving the gear selector out of PARK, you
must turn the ignition switch from the LOCK/OFF
position to the ON/RUN position, 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 engaged the transmission into the PARK posi-
tion:
• When shifting into PARK, pull the gear selector to-
ward 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.
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 leave the vehicle.412 STARTING AND OPERATING
If the transmission temperature exceeds normal operat-
ing limits, the powertrain controller will modify the
transmission shift schedule and expand the range of
torque converter clutch engagement. This is done to
prevent transmission 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
temperature as well as vehicle speed. This feature im-
proves 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
below), 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 tempera-
tures (-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 loaded414 STARTING AND OPERATING
conditions may be reduced. 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
abnormal 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 illuminated. Limp Home Mode allows the
vehicle to be driven to an authorized dealer for service
without damaging the transmission. In the event of a momentary problem, the transmission
can be reset to regain all forward gears by performing the
following steps:
1. Stop the vehicle.
2. Shift the transmission into PARK.
3. Turn the ignition switch to the OFF position.
4. Wait approximately 10 seconds.
5. Restart the engine.
6. Shift into the desired gear range. If the problem is no
longer detected, the transmission will return to normal
operation.
NOTE: Even if the transmission can be reset, we recom-
mend that you visit your authorized dealer at your
earliest possible convenience. Your authorized dealer has
diagnostic equipment to determine if the problem could
recur. 5STARTING AND OPERATING 415
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 “Transfer Case Position Indicator Light” in the
instrument cluster will alert the driver that the vehicle is
in four-wheel drive and that the front and rear drive-
shafts are locked together. This light will illuminate when
the transfer case is shifted into either the 4H or 4L
position. There is no light for the 2H or NEUTRAL
positions on some models.
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 four-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 drivetrain.
NOTE: Do not attempt to make a shift while only the
front or rear wheels are spinning. The front and rear
driveshaft speeds must be equal for the shift to take
place. Shifting while only the front or rear wheels are
spinning can cause damage to the transfer case.
Because four-wheel drive provides improved traction,
there is a tendency to exceed safe turning and stopping
speeds. Do not go faster than road conditions permit.
NOTE: Delayed shifts out of four-wheel drive may be
experienced due to uneven tire wear, low or uneven tire
pressures, excessive vehicle loading, or cold tempera-
tures.424 STARTING AND OPERATING
traction and maximum pulling power for loose, slippery
road surfaces only. Do not exceed 25 mph (40 km/h).
CAUTION!Do not use 4L (Low) range when operating the
vehicle on dry pavement. Driveline hardware dam-
age can result.
Shifting Procedure — Manually Shifted Transfer
Case
2H To 4H
Shifting between 2H and 4H can be made with the
vehicle stopped or in motion. If the vehicle is in motion,
shifts can be made up to 55 mph (88 km/h). With the
vehicle in motion, the transfer case will engage/
disengage faster if you momentarily release the accelera-
tor pedal after completing the shift. Apply a constant
force when shifting the transfer case lever. 2H Or 4H To 4L
With the vehicle rolling at 2 to 3 mph (3 to 5 km/h), shift
the transmission into NEUTRAL. While the vehicle is
coasting at 2 to 3 mph (3 to 5 km/h), shift the transfer
case lever firmly to the desired position. Do not pause in
transfer case NEUTRAL.
NOTE:
• Pausing in transfer case NEUTRAL in vehicles
equipped with an automatic transmission may require
shutting the engine OFF to avoid gear clash while
completing the shift. If difficulty occurs, shift the
transmission into NEUTRAL, hold foot on brake, and
turn the engine OFF. Make shift to the desired mode.
• Shifting into or out of 4L is possible with the vehicle
completely stopped, however difficulty may occur due
to the mating clutch teeth not being properly aligned.
Several attempts may be required for clutch teeth426 STARTING AND OPERATING
3. When the shift is complete, the indicator light for the
selected position will stop flashing and remain ON.
If One Or More Shift Conditions Are Not Met:
1. The indicator light for the current position will remain
ON.
2. The newly selected position indicator light will con-
tinue to flash.
3. The transfer case will not shift.
NOTE: Before retrying a selection, make certain that all
the necessary requirements for selecting a new transfer
case position have been met. To retry the selection, turn
the control knob back to the current position, wait five
seconds, and retry selection. To find the shift require-
ments, refer to the Shifting Procedure for your transfer
case, located in this section. The “SVC 4WD Warning Light” monitors the electronic
shift four-wheel drive system. If this light remains on
after engine start up or illuminates during driving, it
means that the four-wheel drive system is not function-
ing properly and that service is required.
WARNING!Always engage the parking brake when powering
down the vehicle if the “SVC 4WD Warning Light” is
illuminated. Not engaging the parking brake may
allow the vehicle to roll, which may cause personal
injury.
NOTE: Do not attempt to make a shift while only the
front or rear wheels are spinning, as this can cause
damage to driveline components. 5STARTING AND OPERATING 429