Page 400 of 675

▫ Transfer Case Position Indicator Light ..... .427
▫ Electronically Shifted Transfer Case (Four-Position
Switch) — If Equipped ................ .427
▫ Shifting Procedure .................... .431
LIMITED-SLIP DIFFERENTIAL ............ .434
DRIVING ON SLIPPERY SURFACES ........ .434
▫ Acceleration ........................ .434
▫ Traction ........................... .435
DRIVING THROUGH WATER ............ .436
▫ Flowing/Rising Water ................. .436
▫ Shallow Standing Water ................ .436
POWER STEERING .................... .437
▫ Power Steering Fluid Check ............. .438 PARKING BRAKE ..................... .439
BRAKE SYSTEM ...................... .442
▫ Hydraulic Brake Assist ................. .442
ELECTRONIC BRAKE CONTROL SYSTEM . . . .442
▫ Electronic Brake Force Distribution (EBD) . . . .443
▫ Brake System Warning Light ............. .443
▫ Anti-Lock Brake System (ABS) ........... .443
▫ Anti-Lock Brake Warning Light ........... .445
▫ Brake Assist System (BAS) .............. .445
▫ Hill Start Assist (HSA) ................ .446
▫ Traction Control System (TCS) ........... .449
▫ Electronic Stability Control (ESC) ......... .450
▫ Electronic Roll Mitigation (ERM) ......... .454398 STARTING AND OPERATING
Page 416 of 675

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
Page 421 of 675

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
braking 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 possi-
bly resulting 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 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 5STARTING AND OPERATING 419
Page 431 of 675

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
Page 436 of 675

LIMITED-SLIP DIFFERENTIAL
The limited-slip differential provides additional traction
on snow, ice, mud, sand and gravel, particularly when
there is a difference between the traction characteristics
of the surface under the right and left rear wheels. During
normal driving and cornering, the limited-slip unit per-
forms similarly to a conventional differential. On slip-
pery surfaces, however, the differential delivers more of
the driving effort to the rear wheel having the better
traction.
The limited-slip differential is especially helpful during
slippery driving conditions. With both rear wheels on a
slippery surface, a slight application of the accelerator
will supply maximum traction. When starting with only
one rear wheel on an excessively slippery surface, slight
momentary application of the parking brake may be
necessary to gain maximum traction. WARNING!On vehicles equipped with a limited-slip differential
never run the engine with one rear wheel off the
ground since the vehicle may drive through the rear
wheel remaining on the ground. You could lose
control of the vehicle.
Care should be taken to avoid sudden accelerations when
both rear wheels are on a slippery surface. This could
cause both rear wheels to spin, and allow the vehicle to
slide sideways on the crowned surface of a road or in a
turn.
DRIVING ON SLIPPERY SURFACES
Acceleration
Rapid acceleration on snow covered, wet, or other slip-
pery surfaces may cause the driving wheels to pull
erratically to the right or left. This phenomenon occurs434 STARTING AND OPERATING
Page 438 of 675

DRIVING THROUGH WATER
Driving through water more than a few inches/
centimeters deep will require extra caution to ensure
safety and prevent damage to your vehicle.
Flowing/Rising Water
WARNING!Do not drive on or across a road or path where water
is flowing and/or rising (as in storm run-off). Flow-
ing water can wear away the road or path’s surface
and cause your vehicle to sink into deeper water.
Furthermore, flowing and/or rising water can carry
your vehicle away swiftly. Failure to follow this
warning may result in injuries that are serious or
fatal to you, your passengers, and others around you. Shallow Standing Water
Although your vehicle is capable of driving through
shallow standing water, consider the following Cautions
and Warnings before doing so.
WARNING!• Driving through standing water limits your vehi-
cle’s traction capabilities. Do not exceed 5 mph
(8 km/h) when driving through standing water.
• Driving through standing water limits your vehi-
cle’s braking capabilities, which increases stopping
distances. Therefore, after driving through stand-
ing water, drive slowly and lightly press on the
brake pedal several times to dry the brakes.
• Failure to follow these warnings may result in
injuries that are serious or fatal to you, your pas-
sengers, and others around you.436 STARTING AND OPERATING
Page 442 of 675
When the parking brake is applied with the ignition
switch ON, the “Brake Warning Light” in the instrument
cluster will illuminate. NOTE:
• When the parking brake is applied and the automatic
transmission is placed in gear, the “Brake Warning
Light” will flash. If vehicle speed is detected, a chime
will sound to alert the driver. Fully release the parking
brake before attempting to move the vehicle.
• This light only shows that the parking brake is ap-
plied. It does not show the degree of brake application.
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. For vehicles equipped
with an automatic transmission, 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.Parking Brake Release440 STARTING AND OPERATING
Page 443 of 675

The parking brake should always be applied whenever
the driver is not in the vehicle.
WARNING!• 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 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 of a vehicle equipped with
Keyless Enter-N-Go in the ACC or ON/RUN mode.
A child could operate power windows, other con-
trols, 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 leav-
ing your vehicle or it may roll and cause damage or
injury. Also, be certain to leave an automatic trans-
mission in PARK, a manual transmission in RE-
VERSE or first gear. Failure to do so may cause the
vehicle to roll and cause damage or injury.
CAUTION!If the “Brake Warning Light” remains on with the
parking brake released, a brake system malfunction
is indicated. Have the brake system serviced by an
authorized dealer immediately. 5STARTING AND OPERATING 441