speeds will reduce fogging. Interior fogging on the
windshield can be quickly removed by selecting the
defrost mode.
Regular cleaning of the inside of the windows with a
non-filming cleaning solution (vinegar and water works
very well) will help prevent contaminates (cigarette
smoke, perfumes, etc.) from sticking to the windows.
Contaminates increase the rate of window fogging.
Summer Operation
Air conditioned vehicles must be protected with a high
quality antifreeze coolant during summer to provide
proper corrosion protection and to raise the boiling point
of the coolant for protection against overheating. A 50 %
concentration is recommended. Refer to Recommended
Fluids and Genuine Parts for the proper coolant type.
When using the air conditioner in extremely heavy traffic
in hot weather especially when towing a trailer, addi-
tional engine cooling may be required. If this situation isencountered, operate the transmission in a lower gear to
increase engine RPM, coolant flow and fan speed. When
stopped in heavy traffic, it may be necessary to shift into
NEUTRAL and depress the accelerator slightly for fast
idle operation to increase coolant flow and fan speed.
NOTE:On models equipped with Diesel engines, the
idle speed will automatically increase to 1000 rpm at
elevated coolant temperatures to improve engine cooling.
Your air conditioning system is also equipped with an
automatic recirculation system. When the system senses
a heavy load or high heat conditions, it may use partial
Recirculation A/C mode to provide additional comfort.
Winter Operation
When operating the system during the winter months,
make sure the air intake, located directly in front of the
windshield, is free of ice, slush, snow, or other obstruc-
tions.
220 UNDERSTANDING YOUR INSTRUMENT PANEL
NOTE:If the vehicle is started in extremely cold tem-
peratures, the transmission may not shift into Overdrive
and will automatically select the most desirable gear for
operation at this temperature. Normal operation will
resume when the transmission fluid temperature has
risen to a suitable level. Refer also to the Note under
torque converter clutch, later in this section.
If the transmission temperature gets extremely hot, the
transmission will automatically select the most desirable
gear for operation at this temperature. If the transmission
temperature becomes hot enough the TRANS TEMP light
may illuminate and the transmission may downshift out
of Overdrive until the transmission cools down. After
cooldown, the transmission will resume normal opera-
tion.
The transmission will downshift from Overdrive to Drive
if the accelerator pedal is fully depressed at vehicle
speeds above approximately 35 mph (56 km/h).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” button. This will improve
performance and reduce the potential for transmission
overheating or failure due to excessive shifting. When
operating in “TOW/HAUL” mode, 5th gear (if
236 STARTING AND OPERATING
equipped) is disabled and 2-3 and 3-4 shift patterns are
modified. Shifts into Overdrive (4th gear) are allowed
during steady cruise (for improved fuel economy) and
automatic closed-throttle downshifts to 3rd gear (for
improved braking) will occur during steady braking.
The “TOW/HAUL” light will illuminate in the instru-
ment cluster to indicate when the switch has been
activated. Pressing the switch a second time restores
normal operation. If the “TOW/HAUL” mode is desired,
the button must be pressed each time the engine is
started.
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 inhigh gear. When the vehicle speed drops or during
acceleration when the transmission downshifts to second
gear, the clutch automatically disengages.
NOTE:The torque converter clutch will not engage
until the transmission fluid and engine coolant are warm
[usually after 1-3 miles (1.6 - 4.8 km) of driving]. Because
the engine speed is higher when the torque converter
clutch is not engaged, it may seem as if the transmission
is not shifting into Overdrive when cold. This is normal.
Pressing the “TOW/HAUL” button, when the transmis-
sion is sufficiently warm, will demonstrate that the
transmission is able to shift into and out of overdrive.
NOTE:If the vehicle has not been driven in several
days, the first few seconds of operation after shifting the
transmission 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
STARTING AND OPERATING 237
5
•Air Conditioning—turn it off temporarily.
•Hilly Terrain—Turn 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 automatic transmissions are equipped
with a transmission sump oil temperature sensor and
warning light. If elevated transmission temperatures are
encountered, the engine controller will select the most
desirable gear until the transmission temperatures are
reduced. If transmission oil temperatures continue to
rise, a warning light located in the instrument 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, select TOW/HAUL mode 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:
•5800 rpm with 3.7L engines.
•5800 rpm with 4.7L engines.
•5600 rpm with 5.7L engines.
If your vehicle has an automatic transmission and you
tow a trailer frequently, change transmission fluid and
filter(s) according to Maintenance Schedule “B.”
304 STARTING AND OPERATING
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.
•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.
•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 between forward and reverse.
NOTE:Change the automatic transmission fluid and
filter(s) according to Maintenance ScheduleB.
RECREATIONAL TOWING — 4 WHEEL DRIVE
VEHICLES (BEHIND MOTORHOME, ETC.)
Recreational Towing – 2 Wheel Drive Models
Recreational towing 2 Wheel Drive is not allowed.
Towing with the rear wheels on the ground can result in
severe transmission damage.
CAUTION!
Failure to follow these requirements can cause se-
vere damage to the transmission and/or transfer case.
STARTING AND OPERATING 309
5
4. Shift automatic transmission to N (NEUTRAL), or
depress the clutch on manual transmissions.
5. Shift transfer case lever to desired position.
6. Shift automatic transmission into P (Park).
WARNING!
You or others could be injured if you leave the
vehicle unattended with the transfer case in the N
(NEUTRAL) position without first fully engaging
the parking brake. The transfer case N (NEUTRAL)
position disengages both the front and rear drive-
shafts from the powertrain and will allow the ve-
hicle to move regardless of the transmission posi-
tion. The parking brake should always be applied
when the driver is not in the vehicle.
CAUTION!
•Do not use a bumper mounted clamp-on tow bar
on your vehicle. The bumper face bar will be
damaged.
•Do not disconnect the rear driveshaft because
fluid will leak from the transfer case and damage
the internal parts.
312 STARTING AND OPERATING
▫Air Conditioner Maintenance.............362
▫Power Steering — Fluid Check............363
▫Front Suspension Ball Joints..............364
▫Steering Linkage — Inspection............365
▫Half-Shaft Constant Velocity Joints.........365
▫Front Prop Shaft Lubrication — 2500/3500
(4X4) Models........................365
▫Body Lubrication.....................366
▫Windshield Wiper Blades................366
▫Windshield Washers...................366
▫Exhaust System......................367
▫Cooling System.......................368
▫Hoses And Vacuum/Vapor Harnesses.......372▫Brake System........................372
▫Clutch Hydraulic System................374
▫Clutch Linkage.......................374
▫Rear Axle And 4X4 Front Driving Axle
Fluid Level..........................374
▫Transfer Case........................375
▫Manual Transmission..................376
▫Automatic Transmission................377
▫Front Wheel Bearings..................380
▫Selection Of Lubricating Grease...........380
▫Noise Control System Required Maintenance &
Warranty For 3500 2-Wheel Drive And 4-Wheel
Drive Models Over 10,000 Lbs. (4 535 Kg)
Gross Vehicle Weight Rating..............381
346 MAINTAINING YOUR VEHICLE
Lubricant Selection Getrag G56 (6-Speed Manual
Transmission — If Equipped)
This transmission is filled with manual transmission
fluid at the factory. This fluid does not require periodic
changing. If it is necessary to add or change fluid in this
transmission refer to Recommended Fluids, Lubricants
and Genuine Parts for correct fluid type. This is the only
lubricant recommended for use in the Getrag G56 trans-
mission.
Automatic Transmission
Fluid Level Check
The fluid level should be checked when the engine is
fully warmed up and the fluid in the transmission is at
normal operating temperature. Operation of the trans-
mission with an improper fluid level will greatly reduce
the life of the transmission and of the fluid. Check the
fluid level whenever the vehicle is serviced.
Fluid Level Check – 45RFE/545RFE
Check the fluid level while the transmission is at normal
operating temperature 82°C (180°F). This occurs after at
least 15 miles (25 km) of driving. At normal operating
temperature the fluid cannot be held comfortably be-
tween the fingertips.
To check the automatic transmission fluid level properly,
the following procedure must be used:
1. Operate the engine at idle speed and normal operating
temperature.
2. The vehicle must be on level ground.
3. Fully apply the parking brake and press the brake
pedal.
4. Place the gear selector momentarily in each gear
position ending with the lever in P (Park).
MAINTAINING YOUR VEHICLE 377
7