Page 288 of 502

Overdrive Operation
The automatic transmission includes an electronically
controlled Overdrive (fifth and sixth gears). The trans-
mission will automatically shift into the Overdrive gear if
the following conditions are present:
• the shift lever is in the DRIVE position,
• the transmission fluid has reached an adequate tem-
perature,
• the engine coolant (antifreeze) has reached an ad-
equate temperature,
• vehicle speed is sufficiently high, and
• the TOW/HAUL switch has not been activated.
When To Use TOW/HAUL Mode
When driving in hilly areas, towing a trailer, carrying a
heavy load, etc., and frequent transmission shifting oc-
curs, press the TOW/HAUL switch to select 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 trans-
mission will automatically downshift (for engine brak-
ing) during steady braking maneuvers.
TOW/HAUL Switch286 STARTING AND OPERATING
Page 340 of 502

Materials Added To Fuel
All gasolines sold in the United States are required to
contain effective detergent additives. Use of additional
detergents or other additives is not needed under normal
conditions and would result in unnecessary cost. There-
fore, you should not have to add anything to the fuel.
Fuel System Cautions
CAUTION!Follow these guidelines to maintain your vehicle’s
performance:
• The use of leaded gas is prohibited by Federal law.
Using leaded gasoline can impair engine perfor-
mance, damage the emission control system.
(Continued) CAUTION! (Continued)• An out-of-tune engine, or certain fuel or ignition
malfunctions, can cause the catalytic converter to
overheat. If you notice a pungent burning odor or
some light smoke, your engine may be out of tune
or malfunctioning and may require immediate
service. Contact your authorized dealer for service
assistance.
• When pulling a heavy load or driving a fully-
loaded vehicle when the humidity is low and the
temperature is high, use a premium unleaded fuel
to help prevent spark knock. If spark knock per-
sists, lighten the load, or engine piston damage
may result.
(Continued)338 STARTING AND OPERATING
Page 362 of 502

WARNING!Any work done to the vehicle’s electrical system or
wiring should be performed by a qualified automo-
tive technician. If done improperly it may cause
damage to the electrical system wiring and could
result in serious or fatal injury.
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
The “DRIVE” range can be selected when towing. How-
ever, if frequent shifting occurs while in this range, select
“TOW/HAUL” mode or select a lower gear using the
Electronic Range Select (ERS) feature. NOTE: Using “TOW/HAUL” mode or a lower gear
range while operating the vehicle under heavy operating
conditions will improve performance and extend trans-
mission life by reducing excessive shifting and heat build
up. This action will also provide better engine braking.
The automatic transmission fluid and filter should be
changed if you regularly tow a trailer for more than
45 minutes of continuous operation. Refer to “Mainte-
nance Schedule” for the proper maintenance intervals.
NOTE: Check the automatic transmission fluid level
before towing.
Tow/Haul
To reduce potential for automatic transmission overheat-
ing, turn the “TOW/HAUL” feature ON when driving in
hilly areas, or select a lower gear range (using the
Electronic Range Select (ERS) feature) on more severe
grades.360 STARTING AND OPERATING
Page 366 of 502

NOTE: During snowplow usage on vehicles equipped
with outside temperature display, the display may show
higher temperatures than the outside ambient tempera-
ture. The higher displayed temperature is due to blocked
or reduced airflow to the underhood ambient tempera-
ture sensor caused by the snowplow. In addition, on
vehicles equipped with Automatic Temperature Control
(ATC), it is suggested that the interior cabin temperature
be manually controlled should the system not perform as
desired while in automatic mode. Both the outside tem-
perature display and ATC operation will return to nor-
mal when the snowplow is removed.
General Maintenance
Snowplows should be maintained in accordance with the
plow manufacturer’s instructions.
Keep all snowplow electrical connections and battery
terminals clean and free of corrosion. When plowing snow, to avoid transmission and drive-
train damage, the following precautions should be ob-
served.
• Operate with transfer case in 4L when plowing small
or congested areas where speeds are not likely to
exceed 15 mph (24 km/h). At higher speeds operate in
4H.
• Vehicles with automatic transmissions should use 4L
range when plowing deep or heavy snow for extended
periods of time to avoid transmission overheating.
• Do not shift the transmission unless the engine has
returned to idle and wheels have stopped. Make a
practice of stepping on the brake pedal before shifting
the transmission.364 STARTING AND OPERATING
Page 394 of 502

FREEING A STUCK VEHICLE
If the vehicle becomes stuck in snow, sand, or mud, it can
often be moved by a rocking motion. Move the shift lever
rhythmically between DRIVE/1st and REVERSE while
applying slight pressure to the accelerator.
CAUTION!• Racing the engine or spinning the wheels may
lead to transmission overheating and failure. Al-
low the engine to idle with the shift lever in
NEUTRAL for at least one minute after every five
rocking-motion cycles. This will minimize over-
heating and reduce the risk of transmission failure
during prolonged efforts to free a stuck vehicle.
(Continued) CAUTION! (Continued)• When “rocking” a stuck vehicle by moving be-
tween DRIVE/1st and REVERSE, do not spin the
wheels faster than 15 mph (24 km/h), or drivetrain
damage may result.
• Revving the engine or spinning the wheels too fast
may lead to transmission overheating and failure.
It can also damage the tires. Do not spin the
wheels above 30 mph (48 km/h) while in gear (no
transmission shifting occurring).392 WHAT TO DO IN EMERGENCIES
Page 417 of 502

WARNING!• Exhaust gases can injure or kill. They contain
carbon monoxide (CO), which is colorless and
odorless. Breathing it can make you unconscious
and can eventually poison you. To avoid breathing
CO, refer to “Safety Tips/Exhaust Gas” in “Things
To Know Before Starting Your Vehicle” for further
information.
• A hot exhaust system can start a fire if you park
over materials that can burn. Such materials might
be grass or leaves coming into contact with your
exhaust system. Do not park or operate your ve-
hicle in areas where your exhaust system can
contact anything that can burn. CAUTION!• The catalytic converter requires the use of un-
leaded fuel only. Leaded gasoline will destroy the
effectiveness of the catalyst as an emissions con-
trol device and may seriously reduce engine per-
formance and cause serious damage to the engine.
• Damage to the catalytic converter can result if your
vehicle is not kept in proper operating condition.
In the event of engine malfunction, particularly
involving engine misfire or other apparent loss of
performance, have your vehicle serviced promptly.
Continued operation of your vehicle with a severe
malfunction could cause the converter to overheat,
resulting in possible damage to the converter and
vehicle.
7 MAINTAINING YOUR VEHICLE 415
Page 418 of 502

Under normal operating conditions, the catalytic con-
verter will not require maintenance. However, it is im-
portant to keep the engine properly tuned to assure
proper catalyst operation and prevent possible catalyst
damage.
NOTE: Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
In unusual situations involving grossly malfunctioning
engine operation, a scorching odor may suggest severe
and abnormal catalyst overheating. If this occurs, stop
the vehicle, turn off the engine and allow it to cool.
Service, including a tune-up to manufacturer’s specifica-
tions, should be obtained immediately. To minimize the possibility of catalytic converter dam-
age:
• Do not shut off the engine or interrupt the ignition,
when the transmission is in gear and the vehicle is in
motion.
• Do not try to start the engine by pushing or towing the
vehicle.
• Do not idle the engine with any spark plug wires
disconnected or removed, such as when diagnostic
testing, or for prolonged periods during very rough
idle or malfunctioning operating conditions.416 MAINTAINING YOUR VEHICLE
Page 422 of 502

WARNING!• The warning words “DO NOT OPEN HOT” on
the cooling system pressure cap are a safety pre-
caution. Never add engine coolant (antifreeze)
when the engine is overheated. Do not loosen or
remove the cap to cool an overheated engine. Heat
causes pressure to build up in the cooling system.
To prevent scalding or injury, do not remove the
pressure cap while the system is hot or under
pressure.
• Do not use a pressure cap other than the one
specified for your vehicle. Personal injury or en-
gine damage may result. Disposal Of Used Coolant
Used ethylene glycol-based engine coolant (antifreeze) is
a regulated substance requiring proper disposal. Check
with your local authorities to determine the disposal
rules for your community. To prevent ingestion by ani-
mals or children do not store ethylene glycol-based
engine coolant (antifreeze) in open containers or allow it
to remain in puddles on the ground. If ingested by a child
or pet, seek emergency assistance immediately. Clean up
any ground spills immediately.
Checking Coolant Level – 5.7L Engine
With the engine OFF and cold, the level of the engine
coolant should be between the MIN and MAX range on
the dipstick.
To check the coolant level:
1. Open the coolant reservoir.420 MAINTAINING YOUR VEHICLE