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Procedures” in “Maintaining Your Vehicle” for proper
coolant selection. Use of the air Recirculation mode
during Winter months is not recommended because it
may cause window fogging.
Vacation/Storage
Any time you store your vehicle or keep it out of service
(i.e., vacation) for two weeks or more, run the air
conditioning system at idle for about five minutes in
fresh air with the blower setting in high. This will ensure
adequate system lubrication to minimize the possibility
of compressor damage when the system is started again.
Window Fogging and Frosting
Vehicle windows tend to fog on the inside of the glass in
mild, rainy and/or humid weather. Windows may frost
on the inside of the glass in very cold weather. To clear
the windows, select Defrost or Mix mode and increasethe front blower speed. Do not use the Recirculation
mode without A/C for long periods, as fogging may
occur.
NOTE:
Automatic Temperature Controls (ATC) will au-
tomatically adjust the climate control settings to reduce
or eliminate window fogging on the front windshield.
When this occurs, recirculation will be unavailable.
Outside Air Intake
Make sure the air intake, located directly in front of the
windshield, is free of obstructions such as leaves. Leaves
collected in the air intake may reduce airflow, can cause
odor, and if they enter the plenum they could plug the
water drains. In Winter months make sure the air intake
is clear of ice, slush and snow.
4
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WARNING!
Do not downshift for additional engine braking on a
slippery surface. The drive wheels could lose their
grip and the vehicle could skid, causing a collision or
personal injury.
NOTE: To select the proper gear position for maximum
deceleration (engine braking), simply press and hold the
ERS (-) switch down. The transmission will shift to the
range from which the vehicle can best be slowed down.
CAUTION!
When using ERS for engine braking while descend-
ing steep grades, be careful not to overspeed the
engine. Apply the brakes as needed to prevent en-
gine overspeed.
Overdrive Operation
The automatic transmission includes an electronically
controlled Overdrive (fifth and sixth gears). The trans-
mission will automatically shift into Overdrive 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 has reached an adequate tempera-
ture.
• Vehicle speed is sufficiently high.
• 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 occurs,
press the TOW/HAUL switch to activate TOW/HAUL
5
STARTING AND OPERATING 309
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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
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ENGINE COMPARTMENT — 5.7L
1 — Air Cleaner Filter6 — Battery
2 — Automatic Transmission Dipstick 7 — Washer Fluid Reservoir
3 — Engine Oil Fill 8 — Power Distribution Center (Fuses)
4 — Engine Oil Dipstick 9 — Coolant Pressure Cap
5 — Brake Fluid Reservoir 10 — Engine Coolant Reservoir
7
MAINTAINING YOUR VEHICLE 445
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ENGINE COMPARTMENT — 6.4L
1 — Coolant Pressure Bottle6 — Battery
2 — Transmission Dipstick 7 — Power Distribution Center (Fuses)
3 — Engine Oil Fill 8 — Washer Solvent
4 — Engine Oil Dipstick 9 — Power Steering Fluid Reservoir
5 — Brake Fluid Reservoir 10 — Air Cleaner Filter
446 MAINTAINING YOUR VEHICLE
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To minimize the possibility of catalytic converter damage:
•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.
Cooling System
WARNING!
You or others can be badly burned by hot engine
coolant (antifreeze) or steam from your radiator. If
(Continued)
WARNING! (Continued)
you see or hear steam coming from under the hood,
do not open the hood until the radiator has had time
to cool. Never try to open a cooling system pressure
cap when the radiator is hot.
Engine Coolant Checks
Check the engine coolant (antifreeze) protection every 12
months (before the onset of freezing weather, where
applicable). If the engine coolant (antifreeze) is dirty or
rusty in appearance, the system should be drained,
flushed and refilled with fresh coolant. Check the front of
the A/C condenser (if equipped) or radiator for any
accumulation of bugs, leaves, etc. If dirty, clean by gently
spraying water from a garden hose vertically down the
face of the A/C condenser (if equipped) or the back of the
radiator core.
7
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Check the engine cooling system hoses for brittle rubber,
cracking, tears, cuts and tightness of the connection at the
coolant recovery bottle and radiator. Inspect the entire
system for leaks.
With the engine at normal operating temperature (but
not running), check the cooling system pressure cap for
proper vacuum sealing by draining a small amount of
engine coolant (antifreeze) from the radiator drain cock.
The radiator drain cock is located in the lower radiator
tank. If the cap is sealing properly, the engine coolant
(antifreeze) will begin to drain from the coolant expan-
sion bottle. DO NOT REMOVE THE COOLANT PRES-
SURE CAP WHEN THE COOLING SYSTEM IS HOT.Cooling System — Drain Flush And Refill
If the engine coolant (antifreeze) is dirty or contains a
considerable amount of sediment, clean and flush with a
reliable cooling system cleaner. Follow with a thorough
rinsing to remove all deposits and chemicals. Properly
dispose of old engine coolant (antifreeze).
Refer to the “Maintenance Schedule” for the proper
maintenance intervals.
Selection Of Coolant
Refer to “Fluids, Lubricants, and Genuine Parts” in
“Maintaining Your Vehicle” for further information.
462 MAINTAINING YOUR VEHICLE
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CAUTION!
•Mixing of engine coolant (antifreeze) other than
specified Organic Additive Technology (OAT) en-
gine coolant (antifreeze), may result in engine
damage and may decrease corrosion protection.
Organic Additive Technology (OAT) engine cool-
ant is different and should not be mixed with
Hybrid Organic Additive Technology (HOAT) en-
gine coolant (antifreeze) or any “globally compat-
ible” coolant (antifreeze). If a non-OAT engine
coolant (antifreeze) is introduced into the cooling
system in an emergency, the cooling system will
need to be drained, flushed, and refilled with fresh
OAT coolant (conforming to MS-12106), by an
authorized dealer as soon as possible.
(Continued)
CAUTION! (Continued)
•Do not use water alone or alcohol-based engine
coolant (antifreeze) products. Do not use additional
rust inhibitors or antirust products, as they may not
be compatible with the radiator engine coolant and
may plug the radiator.
• This vehicle has not been designed for use with
propylene glycol-based engine coolant (antifreeze).
Use of propylene glycol-based engine coolant (an-
tifreeze) is not recommended.
Adding Coolant
Your vehicle has been built with an improved engine
coolant (OAT coolant conforming to MS-12106) that
allows extended maintenance intervals. This engine cool-
ant (antifreeze) can be used up to ten years or 150,000
miles (240,000 km) before replacement. To prevent reduc-
ing this extended maintenance period, it is important that7
MAINTAINING YOUR VEHICLE 463