If the light remains lit with the engine running, your
vehicle will usually be drivable. However, see an autho-
rized dealer for service as soon as possible. If the light is
flashing when the engine is running, immediate service is
required. You may experience reduced performance, an
elevated/rough idle or engine stall and your vehicle may
require towing.
28. Air Suspension Normal Ride Height Indicator Lamp
– If Equipped
This light will illuminate when the air suspension system
is set to the Normal Ride Height setting. For further
information, refer to “Air Suspension System” in “Start-
ing And Operating”.
29. Air Suspension Off-Road 1 Indicator Lamp – If
Equipped
This light will illuminate when the air suspension system is
set to the Off-Road 1 setting. For further information, refer
to “Air Suspension System” in “Starting And Operating”.
30. Air Suspension Off-Road 2 Indicator Lamp – If
Equipped
This light will illuminate when the air suspension system
is set to the Off-Road 2 setting. For further information,
refer to “Air Suspension System” in “Starting And
Operating”.
31. 4 LOWThis light alerts the driver that the vehicle is in
the four-wheel drive LOW mode. The front and
rear driveshafts are mechanically locked to-
gether forcing the front and rear wheels to
rotate at the same speed. Low range provides a greater
gear reduction ratio to provide increased torque at the
wheels.
For further information on four-wheel drive operation
and proper use, refer to “Four-Wheel Drive Operation —
If Equipped” in “Starting And Operating”.
4
UNDERSTANDING YOUR INSTRUMENT PANEL 211
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 transmis-
sion, top overdrive gear is also inhibited until the trans-
mission fluid is warm, and during extremely cold tem-
peratures (-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 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 accel-
erate under heavily loaded conditions may be reduced.
306 STARTING AND OPERATING
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 automati-
cally 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.
NOTE:
•The torque converter clutch will not engage (and
66RFE-equipped trucks will not shift to sixth gear),
until the transmission fluid and engine coolant are
warm [usually after 1 to 3 miles (2 to 5 km) of driving].
Because engine speed is higher when the torque con-
verter clutch is not engaged, it may seem as if the
transmission is not shifting properly when cold. This is
normal. Using the Electronic Range Select (ERS) shift control, when the transmission is sufficiently warm,
will demonstrate that the transmission is able to shift
into and out of Overdrive.
• If the vehicle has not been driven for several days, the
first few seconds of operation after shifting the trans-
mission into gear may seem sluggish. This is due to the
fluid partially draining from the torque converter into
the transmission. This condition is normal and will not
cause damage to the transmission. The torque con-
verter will refill within five seconds after starting the
engine.
FOUR-WHEEL DRIVE OPERATION — IF
EQUIPPED
Four-wheel drive trucks are equipped with either a
manually shifted transfer case or an electronically shifted
transfer case. Refer to the operating instructions for your
transfer case, located in this section for further informa-
tion.
5
STARTING AND OPERATING 311
Electronically Shifted Transfer Case
(Four-Position Switch) — If Equipped
This is an electronic shift transfer case and is operated by
the 4WD Control Switch (Transfer Case Switch), which is
located on the instrument panel.This electronically shifted transfer case provides four
mode positions:
•
Two-wheel drive high range (2WD)
• Four-wheel drive lock range (4WD LOCK)
• Four-wheel drive low range (4WD LOW)
• Neutral (NEUTRAL)
This electronically shifted transfer case is designed to be
driven in the two-wheel drive position (2WD) for normal
street and highway conditions on dry, hard surfaced
roads.
When additional traction is required, the transfer case
4WD LOCK and 4WD LOW positions can be used to
maximize torque to the front driveshaft, forcing the front
and rear wheels to rotate at the same speed. This is
accomplished by rotating the 4WD Control Switch to the
desired position. Refer to “Shifting Procedure” in this
section for specific shifting instructions. The 4WD LOCK
Transfer Case Switch (Four-Position)
316 STARTING AND OPERATING
WARNING!
You or others could be injured or killed if you leave
the vehicle unattended with the transfer case in the
NEUTRAL position without first fully engaging the
parking brake. The transfer case NEUTRAL position
disengages both the front and rear drive shafts from
the powertrain and will allow the vehicle to move
regardless of the transmission position. The parking
brake should always be applied when the driver is
not in the vehicle.
For additional information on the appropriate use of each
transfer case mode position, see the information below:
2WD
Rear Wheel Drive High Range — This range is for normal
street and highway driving on dry, hard surfaced roads. 4WD LOCK
Four-Wheel Drive Lock Range — This range maximizes
torque to the front driveshaft, forcing the front and rear
wheels to rotate at the same speed. This range provides
additional traction for loose, slippery road surfaces only.
4WD LOW
Four-Wheel Drive Low Range — This range provides low
speed four-wheel drive. It maximizes torque to the front
driveshaft, forcing the front and rear wheels to rotate at
the same speed. This range provides additional traction
and maximum pulling power for loose, slippery road
surfaces only. Do not exceed 25 mph (40 km/h).
NEUTRAL (N)
Neutral — This range disengages both the front and rear
driveshafts from the powertrain. To be used for flat
5
STARTING AND OPERATING 319
WARNING!(Continued)
•The ABS cannot prevent collisions, including those
resulting from excessive speed in turns, following
another vehicle too closely, or hydroplaning.
• The capabilities of an ABS-equipped vehicle must
never be exploited in a reckless or dangerous
manner which could jeopardize the user’s safety or
the safety of others.
Traction Control System (TCS) — If Equipped
The TCS monitors the amount of wheel spin of each of
the driven wheels. If wheel spin is detected, brake
pressure is applied to the slipping wheel(s), and engine
power is reduced to provide enhanced acceleration and
stability. A feature of the TCS functions similarly to a
limited-slip differential and controls the wheel spin
across a driven axle. If one wheel on a driven axle is
spinning faster than the other, the system will apply the brake of the spinning wheel. This will allow more engine
torque to be applied to the wheel that is not spinning.
This feature remains active even if TCS and ESC are in
the “Partial Off” mode. Refer to “Electronic Stability
Control (ESC)” in this section of this manual. This brake
pressure modulation transfers drive torque from slipping
to non-slipping wheels to provide optimal forward trac-
tion.
Hill Start Assist (HSA) — If Equipped
The HSA system is designed to assist the driver in
launching a vehicle on an incline. HSA will maintain the
level of brake pressure the driver inputs for a short
duration once the driver takes his foot off of the brake
pedal. If the driver does not apply the throttle during this
short duration, the system will release brake pressure
and the vehicle will roll down the incline. The system will
release brake pressure in proportion to the amount of
throttle applied.
334 STARTING AND OPERATING
In this mode, ESC and TCS except for the “limited slip”
feature described in the TCS section are turned off until
the vehicle reaches a speed of 40 mph (64 km/h). At
40 mph (64 km/h) the system returns to “Partial Off”
mode, described above. When the vehicle speed drops
below 35 mph (56 km/h) the ESC system shuts off. ESC
is off at low vehicle speeds so that it will not interfere
with off-road driving but ESC function returns to provide
the stability feature at speeds above 40 mph (64 km/h).
The “ESC Off Indicator Light” will always be illuminated
when ESC is off. To turn ESC on again, momentarily
press the “ESC Off” switch. This will restore the normal
“ESC On” mode of operation.
“ESC Off” is the only operating mode for ESC in 4WD
LOW. Whenever the vehicle is started in 4WD LOW or
the transfer case (if equipped) is shifted from 4WD LOCK
or NEUTRAL, to 4WD LOW, the ESC system will be in
this mode.WARNING!
In the ESCFull Offmode, the engine torque reduc-
tion and stability features are disabled. Therefore,
the enhanced vehicle stability offered by ESC is
unavailable. In an emergency evasive maneuver the
ESC system will not engage to assist in maintaining
stability. “ESC Off” mode is intended for off-
highway or off-road use only.
ESC Activation/Malfunction Indicator Light And
ESC OFF Indicator Light
The “ESC Activation/Malfunction Indicator
Light” in the instrument cluster will come on
when the ignition switch is turned to the ON
position. It should go out with the engine
running. If the “ESC Activation/Malfunction Indicator
Light” comes on continuously with the engine running, a
5
STARTING AND OPERATING 341
WHAT TO DO IN EMERGENCIES
CONTENTS
HAZARD WARNING FLASHERS ...........420
WHEEL AND TIRE TORQUE
SPECIFICATIONS ..................... .420
▫ Torque Specifications ..................420
JACKING AND TIRE CHANGING ..........423
▫ 4500/5500 Models .....................423
▫ Preparations For Jacking .................423
▫ Jacking Instructions ....................425
HOISTING .......................... .431
JUMP-STARTING PROCEDURES ...........431
▫ Preparations For Jump-Start ..............431
▫ Jump-Starting Procedure ................433
FREEING A STUCK VEHICLE .............435
EMERGENCY TOW HOOKS — IF EQUIPPED . .437
SHIFT LEVER OVERRIDE ................437
TOWING A DISABLED VEHICLE ...........438
▫ Two-Wheel Drive Models ................440
▫ Four-Wheel Drive Models ................441
6