Transmission Temperature Indicator Light
Yellow Telltale
Light What It Means
Transmission Temperature Indicator Light
This light indicates that the transmission fluid temperature is running hot. This may occur with
severe usage, such as trailer towing. If this light turns on, safely pull over and stop the vehicle.
Then, shift the transmission into NEUTRAL and run the engine at idle or faster until the light
turns off.
WARNING!If you continue operating the vehicle when the Trans-
mission Temperature Warning Light is illuminated you
could cause the fluid to boil over, come in contact with
hot engine or exhaust components and cause a fire. CAUTION!Continuous driving with the Transmission Tempera-
ture Warning Light illuminated will eventually cause
severe transmission damage or transmission failure. 4UNDERSTANDING YOUR INSTRUMENT PANEL 211
• Transmission Cool Ready To Drive
• Trailer Brake Disconnected
• Service Transmission
• Service Shifter
• Engage Park Brake To Prevent Rolling
• Transmission Too Cold Idle With Engine On
• Washer Fluid Low
The Reconfigurable Telltales section is divided into the
white telltales area on the right, yellow telltales in the
middle, and red telltales on the left.
Battery Saver On/Battery Saver Mode Message —
Electrical Load Reduction Actions — If Equipped
This vehicle is equipped with an Intelligent Battery Sensor
(IBS) to perform additional monitoring of the electrical
system and status of the vehicle battery.
In cases when the IBS detects charging system failure, or
the vehicle battery conditions are deteriorating, electrical
load reduction actions will take place to extend the driving
time and distance of the vehicle. This is done by reducing
power to or turning off non-essential electrical loads. Load reduction is only active when the engine is running.
It will display a message if there is a risk of battery
depletion to the point where the vehicle may stall due to
lack of electrical supply, or will not restart after the current
drive cycle.
When load reduction is activated, the message “Battery
Saver On” or “Battery Saver Mode” will appear in the
instrument cluster.
These messages indicate the vehicle battery has a low state
of charge and continues to lose electrical charge at a rate
that the charging system cannot sustain.
NOTE:
• The charging system is independent from load reduc-
tion. The charging system performs a diagnostic on the
charging system continuously.
• If the Battery Charge Warning Light is on it may indicate
a problem with the charging system. Refer to “Battery
Charge Warning Light” in “Understanding Your Instru-
ment Panel” for further information.232 UNDERSTANDING YOUR INSTRUMENT PANEL
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 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 sig-
nificant additional heat load on the cooling system. Down-
shifting 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 maxi-
mum 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 sec-
tion).
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. 5STARTING AND OPERATING 331
• 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. 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 Switch334 STARTING AND OPERATING
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. 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 converter 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 Over-
drive.
• If the vehicle has not been driven for several days, the
first few seconds of operation after shifting the transmis-
sion 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 converter
will refill within five seconds after starting the engine. 5STARTING AND OPERATING 335
CAUTION!Prolonged operation of the steering system at the end
of the steering wheel travel will increase the steering
fluid temperature and it should be avoided when
possible. Damage to the power steering pump may
occur.
Power Steering Fluid Check
Checking the power steering fluid level at a defined service
interval is not required. The fluid should be checked at
every oil change if a leak is suspected, abnormal noises are
apparent, and/or the system is not functioning as antici-
pated. Coordinate inspection efforts through an authorized
dealer.
CAUTION!Do not use chemical flushes in your power steering
system as the chemicals can damage your power steer-
ing components. Such damage is not covered by the
New Vehicle Limited Warranty. WARNING!Fluid level should be checked on a level surface and
with the engine off to prevent injury from moving
parts and to ensure accurate fluid level reading. Do not
overfill. Use only manufacturer’s recommended power
steering fluid.
If necessary, add fluid to restore to the proper indicated
level. With a clean cloth, wipe any spilled fluid from all
surfaces. Refer to “Fluids, Lubricants And Genuine Parts”
in “Maintaining Your Vehicle” for further information.
PARKING BRAKE
Before leaving the vehicle, make sure that the parking
brake is fully applied, the engine is off and the key fob is
removed from the ignition switch. Also, be certain to leave
an automatic transmission in PARK, or manual transmis-
sion in REVERSE or first gear.
The foot operated parking brake is located below the lower
left corner of the instrument panel. To apply the parking
brake, firmly push the parking brake pedal fully. To release
the parking brake, pull the parking brake release handle.350 STARTING AND OPERATING
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 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 au-
thorized dealer immediately.
BRAKE SYSTEM
If power assist is lost for any reason (for example, repeated
brake applications with the engine off), the brakes will still
function. However, you will experience a substantial in-
crease in braking effort to stop the vehicle. If either the front or rear hydraulic system loses normal
braking capability, the remaining system will still function
with some loss of overall braking effectiveness. This will be
evident by increased pedal travel during application,
greater pedal force required to slow or stop, and activation
of the “Brake Warning Light” and the “ABS Warning
Light” (if equipped) during brake use.
The brake system power assist is provided by a hydro-boost
unit which shares fluid with the power steering system. You
may experience some clicking or hissing noises from the
hydro-boost system during hard braking conditions.
NOTE: Under cold temperatures, pedal effort will be
higher than normal until the power steering fluid reaches
operating temperature.
Hydraulic Brake Assist
The brake system power assist is provided by a hydro-boost
unit which shares fluid with the power steering system. You
may experience some clicking or hissing noises from the
hydro-boost system during hard braking conditions.
NOTE: Under cold temperatures, pedal effort will be
higher than normal until the power steering fluid reaches
operating temperature.352 STARTING AND OPERATING
Towing Tips
Before setting out on a trip, practice turning, stopping and
backing the trailer up in an area away from heavy traffic.
Automatic Transmission — If Equipped
The DRIVE range can be selected when towing. The
transmission controls include a drive strategy to avoid
frequent shifting when towing. However, if frequent shift-
ing does occur while in DRIVE, select TOW/HAUL mode
or select a lower gear range (using the Electronic Range
Select (ERS) shift control).
NOTE: Using TOW/HAUL mode, or selecting a lower
gear range (using the ERS shift control) while operating the
vehicle under heavy loading conditions will improve per-
formance and extend transmission life by reducing exces-
sive shifting and heat build up. This action will also
provide better engine braking.
When towing a loaded trailer up steep grades at low
speeds (20 mph [32 km/h] or below), holding your vehicle
in first gear (using the ERS shift control) can help to avoid
transmission overheating. If you regularly tow a trailer for more than 45 minutes of
continuous operation, then change the transmission fluid
and filter(s) as specified for police, taxi, fleet, or frequent
trailer towing. Refer to the “Maintenance Schedule” for
the proper maintenance intervals.
NOTE: Check the automatic transmission fluid level be-
fore towing.
Tow/Haul Mode
To reduce potential for automatic transmission overheat-
ing, activate TOW/HAUL mode when driving in hilly
areas, or select a lower gear range (using the Electronic
Range Select (ERS) shift control) on more severe grades.
Electronic Speed Control — If Equipped
• Do not use in hilly terrain or with heavy loads.
• When using the speed control, if you experience speed
drops greater than 10 mph (16 km/h), disengage until
you can get back to cruising speed.
• Use speed control in flat terrain and with light loads to
maximize fuel efficiency. 5STARTING AND OPERATING 415