Page 246 of 532

Snow Tires ...........................324
Tire Rotation Recommendations ............325
▫ Dual Rear Wheels .....................326
Engine Runaway .......................327
Fuel Requirements ......................327
▫ Fuel Requirements (Gas Engines) ..........327
▫ Fuel Requirements (6.7L Diesel Engines) .....331
Adding Fuel ..........................333
▫ Adding Fuel (Gas Engines) ..............333
▫ Adding Fuel (Diesel Engines) .............335
Vehicle Loading ........................338
▫ Certification Label .....................338
TrailerTowing .........................341 ▫ Common Towing Definitions .............341
▫ Trailer Hitch Classification ...............345
▫ Trailer Towing Weights (Maximum Trailer Weight
Ratings) ............................346
▫ Trailer And Tongue Weight ..............346
▫ Towing Requirements ..................347
▫ TowingTips .........................352
▫ Trailer Towing Mirrors — If Equipped ......354
Snowplow ............................355
▫ Before Plowing .......................356
▫ Snowplow Prep Package Model Availability . . 357
▫ Over The Road Operation With Snowplow
Attached ...........................358
▫ Methods For Removing Snow ............358246 STARTING AND OPERATING
Page 247 of 532
▫ Operating Tips .......................358
▫ General Maintenance ...................359
Recreational Towing (Behind Motorhome, Etc.) . . 360 ▫ Recreational Towing – 2 Wheel Drive Models . 360
▫ Recreational Towing – 4 Wheel Drive Models . 360 STARTING AND OPERATING 247
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Page 250 of 532

CAUTION!To prevent damage to the starter, do not crank the
engine for more than 15 seconds at a time. Wait 10 to
15 seconds before trying again.
WARNING!Never pour fuel or other flammable liquids into the
throttle body air inlet opening in an attempt to start
the vehicle. This could result in a flash fire causing
serious personal injury. WARNING!Do not attempt to push or tow your vehicle to get it
started. Vehicles equipped with an automatic trans-
mission cannot be started this way. Unburned fuel
could enter the catalytic converter and once the
engine has started, ignite and damage the converter
and vehicle. If the vehicle has a discharged battery,
booster cables may be used to obtain a start from a
booster battery or the battery in another vehicle. This
type of start can be dangerous if done improperly.
See section 6 of this manual for the proper jump
starting procedures and follow them carefully.
If the engine has been flooded, it may start to run, but not
have enough power to continue running when the key is250 STARTING AND OPERATING
Page 266 of 532

NOTE: For optimum braking power it is recommended
to use the Exhaust Brake while in Tow/Haul Mode.
The purpose of the exhaust brake (engine braking) fea-
ture is to supply negative (braking) torque to the engine.
Typically, the engine braking is used for, but not limited
to, vehicle towing applications where vehicle braking can
be achieved by the internal engine power, thereby spar-
ing the mechanical brakes of the vehicle.
Benefits of the exhaust brake are:
• vehicle driving control
• reduced brake fade
• longer brake life
• faster cab warm-up. AUTOMATIC TRANSMISSION
CAUTION!Damage to the transmission may occur if the follow-
ing precautions are not observed:
• Shift into PARK only after the vehicle has come to
a complete stop.
• Shift into or out of REVERSE only after the
vehicle has come to a complete stop and the
engine is at idle speed.
• Do not shift from REVERSE, PARK, or NEUTRAL
into any forward gear when the engine is above
idle speed.
• Before shifting into any gear, make sure your foot
is firmly on the brake pedal.266 STARTING AND OPERATING
Page 267 of 532

WARNING!It is dangerous to shift the selector lever out of “P” or
“N” if the engine speed is higher than idle speed. If
your foot is not firmly on the brake pedal, the
vehicle could accelerate quickly forward or in re-
verse. You could lose control of the vehicle and hit
someone or something. Only shift into gear when
the engine is idling normally and when your right
foot is firmly on the brake pedal.
Automatic Transmission with Overdrive (5 Speed
545RFE) — If Equipped
The gear shift selector display, located in the instrument
panel cluster, indicates the transmission gear range (the
selector is illuminated for night driving). The selector
lever is mounted on the right side of the steering column.
You must depress the brake pedal, to pull the selector
lever out of park (P) position (Brake Interlock System). To drive, move the selector lever from Park or Neutral to the
desired drive position. Pull the selector lever toward you
when shifting into Reverse, Second, First or Park, or
when shifting out of Park.
Gear Ranges
DO NOT race the engine when shifting from Park or
Neutral position into another gear range.
“P” Park
This gear position supplements the parking brake by
locking the transmission. The engine can be started in
this range. Never use Park while the vehicle is in motion.
Apply the parking brake when leaving the vehicle in this
range. Always apply parking brake first, then place the
selector in Park position. On 4-wheel drive vehicles be
sure that the transfer case is in a drive position! STARTING AND OPERATING 267
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Page 268 of 532

WARNING!Never use Park position on an automatic transmis-
sion as a substitute for the parking brake. Always
apply parking brake fully when parked to guard
against vehicle movement and possible injury or
damage.
WARNING!Your vehicle could move and injure you and others if
it is not completely in P (Park). Check by trying to
move the gearshift lever back and forth without first
pulling it toward you after you have set it in P. Make
sure it is in Park before leaving the vehicle. WARNING!It is dangerous to shift the selector lever out of “P” or
“N” if the engine speed is higher than idle speed. If
your foot is not firmly on the brake pedal, the
vehicle could accelerate quickly forward or in re-
verse. You could lose control of the vehicle and hit
someone or something. Only shift into gear when
the engine is idling normally and when your right
foot is firmly on the brake pedal.
“R” Reverse
Use this range only after the vehicle has come to a
complete stop.268 STARTING AND OPERATING
Page 270 of 532

• vehicle speed is above approximately 30 mph (48
km/h);
• the “TOW HAUL O/D OFF” switch has not been
activated;
• transmission has reached normal operating tempera-
ture.
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).270 STARTING AND OPERATING
Page 271 of 532

When To Use “TOW HAUL” and “O/D OFF”
Modes
When driving in hilly areas, towing a trailer, carrying a
heavy load, etc., and frequent transmission shifting oc-
curs, press the “TOW HAUL O/D OFF” button once to
select TOW HAUL. 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 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. Pressing the “TOW HAUL O/D OFF” button a
second time to select O/D OFF will disable 4th and 5th
gear completely, which should eliminate any excessive
transmission shifting.
The “TOW HAUL” or “O/D OFF” light will illuminate in
the instrument cluster to indicate when the switch has
been activated. Pressing the switch a third time restores
normal operation. If the “TOW HAUL” or “O/D OFF”
modes are desired, the button must be pressed each time
the engine is started.Tow Haul O/D Off Switch STARTING AND OPERATING 271
5