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WARNING!
²Always 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
transmission in Park, a manual transmission in
Reverse or first gear. Failure to do so may allow
the vehicle to roll and cause damage or injury.
²Leaving children in a vehicle unattended is dan-
gerous for a number of reasons. A child or others
could be injured. Children should be warned not
to touch the parking brake or the gear selector
lever. Don't leave the keys in the ignition. A child
could operate power windows, other controls, or
move the vehicle.
²Be sure the parking brake is fully disengaged before
driving, failure to do so can lead to brake problems
due to excessive heating of the rear brakes.
When parking on a hill, turn the front wheels toward the
curb on a downhill grade and away from the curb on an
uphill grade.
The parking brake should always be applied whenever
the driver is not in the vehicle.
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 increase in braking effort to stop the vehicle.
If either the front or rear hydraulic systems lose normal
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 activa-
tion of the BRAKE warning lamp and the ABS lamp (if
equipped) during brake use.
STARTING AND OPERATING 239
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NOTE:
²These mirrors are power adjustable and heated.
²The passenger side main mirror is flat.
Cooling System Tips Ð Trailer Towing
To reduce potential for engine and transmission over-
heating, take the following actions in high ambient
temperatures:
²City DrivingÐwhen stopped, put the transmission in
N (Neutral) and increase the engine idle speed.
280 STARTING AND OPERATING
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²Highway DrivingÐreduce your speed.
²Air ConditioningÐturn it off temporarily.
²Hilly TerrainÐTurn overdrive off.
See Cooling System Operating information in the Service
and Maintenance section of this manual for more infor-
mation.
Automatic Transmission Oil Temperature Warning
Light
All vehicles with heavy duty transmission oil cooling are
equipped with a transmission sump oil temperature
sensor and warning light. If elevated transmission tem-
peratures are encountered, the engine controller will
select the most desirable gear until the transmission
temperatures are reduced. If transmission oil tempera-
tures continue to rise, a warning light located in theinstrument cluster will illuminate. If this should occur,
stop the vehicle, shift to Neutral, and run the engine at
idle or faster until the light goes off.
Towing With An Automatic Transmission
Vehicles equipped with an automatic transmission may
shift into and out of Overdrive, or a lower gear, when
driving in hilly areas, when heavily loaded, or when
towing into heavy winds.
When this condition occurs, press the ªTOW/HAULº
button or shift into a lower gear to prevent excessive
transmission wear and/or overheating, and to provide
better engine braking.
NOTE:Do not exceed the following RPM while manu-
ally downshifting:
²5.9L Diesel Engines 3200 RPM.
STARTING AND OPERATING 281
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NOTE:During snowplow usage on vehicles equipped
with an overhead console module, the outside tempera-
ture display will show higher temperatures than the
outside ambient temperature. The higher displayed tem-
perature is due to blocked or reduced airflow to the
underhood ambient temperature sensor by the snow-
plow. This is common and outside temperature display
operation will return to normal 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 driv-
etrain damage, the following precautions should be ob-
served.
²Operate 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.
²Vehicles with 48RE transmissions should use 4L range
when plowing deep or heavy snow for extended
periods of time to avoid transmission overheating.
²Do 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.
STARTING AND OPERATING 285
5
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WARNING!
Any procedure other than above could result in:
1. Personal injury caused by electrolyte squirting
out the battery vent;
2. Personal injury or property damage due to battery
explosion;
3. Damage to charging system of booster vehicle or
of immobilized vehicle.
With Portable Starting Unit
There are many types of these units available. Follow the
manufacturer's instructions for necessary precautions
and operation.
CAUTION!
It is very important that the starting unit operating
voltage does not exceed 12 Volts D.C. or damage to
battery, starter motor, alternator, or electrical system
may occur.
FREEING A STUCK VEHICLE
If vehicle becomes stuck in snow, sand, or mud, it can
often be moved by a rocking motion. Move the gear
selector rhythmically between DRIVE and REVERSE,
while applying slight pressure to the accelerator.
In general, the least amount of accelerator pedal pressure
to maintain the rocking motion without spinning the
wheels or racing the engine is most effective. Racing the
engine or spinning the wheels, due to the frustration of
not freeing the vehicle, may lead to transmission over-
heating and failure. Allow the engine to idle with the
WHAT TO DO IN EMERGENCIES 313
6
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transmission selector in NEUTRAL for at least one
minute after every five rocking-motion cycles. This will
minimize overheating and reduce the risk of transmis-
sion failure during prolonged efforts to free a stuck
vehicle.
EMERGENCY TOW HOOKS Ð IF EQUIPPED
Your vehicle may be equipped with emergency tow
hooks.
WARNING!
Chains are not recommended for freeing a stuck
vehicle. Chains may break, causing serious injury or
death.
WARNING!
Stand clear of vehicles when pulling with tow
hooks. Tow straps and chains may break, causing
serious injury.
CAUTION!
Tow hooks are for emergency use only, to rescue a
vehicle stranded off road. Do not use tow hooks for
tow truck hookup or highway towing. You could
damage your vehicle.
314 WHAT TO DO IN EMERGENCIES
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Cooling System
Cooling System Maintenance
At the intervals shown in the Maintenance Schedules
Section of the manual, the system should be drained,
flushed and filled.
Inspection
Coolant protection checks should be made every 12
months (prior to the onset of freezing weather, where
applicable). If coolant is dirty or rusty in appearance, the
system should be drained, flushed and refilled with fresh
coolant as specified.
Inspect the entire cooling system for leaks. Check the face
of the radiator for any accumulation of bugs, leaves, or
other foreign matter. If dirty, clean the radiator core with
a garden hose. With the engine OFF, gently spray water
from the back of the radiator core. Check coolant bottle
tube for condition and tightness of connections at coolant
bottle and radiator.Check the coolant pressure cap and coolant bottle for
proper vacuum sealing. With the engine at normal oper-
ating temperature, note the level of the coolant in the
coolant bottle. Without removing the pressure cap (with
the engine off), drain a small amount of coolant from the
radiator drain cock. If the coolant level in the coolant
bottle drops, the system is sealing properly.
Extremely cold ambient temperature may require the
addition of a ªwinter frontº for effective operation of the
cab heating/cooling system. Make certain that a percent-
age of the radiator is exposed for adequate air flow
through the charge air cooler and automatic transmission
oil cooler. The percentage of opening must be increased
with the increasing ambient air temperature and/or
engine load. If the cooling fan can be heard cycling
frequently, increase the size of the opening in the winter
front.
MAINTAINING YOUR VEHICLE 343
7