Page 251 of 411

5-20
Engine Fan Noise
Your vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the fan is spinning slower and the clutch is
not fully engaged. This improves fuel economy and
reduces fan noise. Under heavy vehicle loading, trailer
towing and/or high outside temperatures, the fan
speed increases as the clutch more fully engages. So
you may hear an increase in fan noise. This is normal
and should not be mistaken as the transmission slipping
or making extra shifts. It is merely the cooling system
functioning properly. The fan will slow down when
additional cooling is not required and the clutch
partially disengages.
You may also hear this fan noise when you start
the engine. It will go away as the fan clutch
partially disengages.
If a Tire Goes Flat
It's unusual for a tire to ªblow outº while you're driving,
especially if you maintain your tires properly. If air goes
out of a tire, it's much more likely to leak out slowly.
But if you should ever have a ªblowout,º here are a few
tips about what to expect and what to do:
If a front tire fails, the flat tire will create a drag that
pulls the vehicle toward that side. Take your foot off
the accelerator pedal and grip the steering wheel firmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
A rear blowout, particularly on a curve, acts much like
a skid and may require the same correction you'd use
in a skid. In any rear blowout, remove your foot from
the accelerator pedal. Get the vehicle under control by
steering the way you want the vehicle to go. It may be
very bumpy and noisy, but you can still steer. Gently
brake to a stop
-- well off the road if possible.
If a tire goes flat, the next part shows how to use your
jacking equipment to change a flat tire safely.
Page 253 of 411
5-22 Removing the Spare Tire and Tools
Your spare tire is stored underneath the rear of your
vehicle. You will use the ratchet and extension to lower
the spare tire.A flat rear tire reduces clearance to remove the spare
tire. If there is less than 12 inches (30.48 cm) between
the ground and the rear bumper or any trailer hitch,
jack up the vehicle until the flat tire is off the ground.
(See ªRemoving the Flat Tireº and ªInstalling the
Spare Tire,º in the Index.
Unless your vehicle has a flat rear tire, do not remove or
restore a tire from/to a storage position under the vehicle
while the vehicle is supported by a jack. Always tighten
the tire fully against the underside of the vehicle
when restoring.
If you have a vehicle which was completed from a
cab and chassis, refer to the information from the
body supplier/installer.
The spare tire is a full
-size tire, like the other tires on
your vehicle.
Page 283 of 411

6-16 When to Change Engine Oil
If any one of these is true for you, use the short trip/city
maintenance schedule:
Most trips are less than 5 miles (8 km). This is
particularly important when outside temperatures are
below freezing.
Most trips include extensive idling (such as frequent
driving in stop
-and-go traffic).
You frequently tow a trailer or use a carrier on top of
your vehicle.
The vehicle is used for delivery service, police, taxi
or other commercial application.
Driving under these conditions causes engine oil to
break down sooner. If any one of these is true for your
vehicle, then you need to change your oil and filter
every 3,000 miles (5 000 km) or 3 months
-- whichever
occurs first.
If none of them is true, use the long trip/highway
maintenance schedule. Change the oil and filter every
7,500 miles (12 500 km) or 12 months
-- whichever
occurs first. Driving a vehicle with a fully warmed
engine under highway conditions will cause engine oil
to break down slower.
What to Do with Used Oil
Used engine oil contains certain elements that may be
unhealthy for your skin and could even cause cancer.
Don't let used oil stay on your skin for very long. Clean
your skin and nails with soap and water, or a good hand
cleaner. Wash or properly throw away clothing or rags
containing used engine oil. See the manufacturer's
warnings about the use and disposal of oil products.
Used oil can be a threat to the environment. If you
change your own oil, be sure to drain all the oil from the
filter before disposal. Never dispose of oil by putting it
in the trash, pouring it on the ground, into sewers, or
into streams or bodies of water. Instead, recycle it by
taking it to a place that collects used oil. If you have a
problem properly disposing of your used oil, ask your
dealer, a service station or a local recycling center
for help.
Page 286 of 411

6-19
Automatic Transmission Fluid
If your vehicle has a diesel engine, see ªAutomatic
Transmission Fluidº in the Diesel Supplement.
When to Check and Change
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change both the fluid and filter every 50,000 miles
(83 000 km) if the vehicle's GVWR is over 8,600 or
if the vehicle is mainly driven under one or more of
these conditions:
In heavy city traffic where the outside temperature
regularly reaches 90F (32C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or delivery service.
If your vehicle's GVWR is not over 8,600 and you do not
use your vehicle under any of these conditions, change the
fluid and filter every 100,000 miles (166 000 km).
See ªScheduled Maintenance Servicesº in the Index.
How to Check
Because this operation can be a little difficult, you may
choose to have this done at the dealership service department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
NOTICE:
Too much or too little fluid can damage your
transmission. Too much can mean that some of
the fluid could come out and fall on hot engine
parts or exhaust system parts, starting a fire.
Too little fluid could cause the transmission to
overheat. Be sure to get an accurate reading if
you check your transmission fluid.
Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:
When outside temperatures are above 90F (32C).
At high speed for quite a while.
In heavy traffic
-- especially in hot weather.
While pulling a trailer.
Page 344 of 411

Scheduled Maintenance
7-5
Short Trip/City Definition
Follow the Short Trip/City Scheduled Maintenance if
any one of these conditions is true for your vehicle:
Most trips are less than 5 miles (8 km). This is
particularly important when outside temperatures
are below freezing.
Most trips include extensive idling (such as frequent
driving in stop
-and-go traffic).
You frequently tow a trailer or use a carrier on top
of your vehicle.
If the vehicle is used for delivery service, police,
taxi or other commercial application.
One of the reasons you should follow this schedule
if you operate your vehicle under any of these
conditions is that these conditions cause engine oil
to break down sooner.
Short Trip/City Intervals
At 3,000 Miles (5 000 km): Drive Axle Service
(2500 and 3500 Series with locking differential only).
Every 3,000 Miles (5 000 km): Engine Oil and Filter
Change (or 3 months, whichever occurs first). Chassis
Lubrication (or 3 months, whichever occurs first).
Drive Axle Fluid Check.
Every 6,000 Miles (10 000 km): Tire Rotation.
Every 15,000 Miles (25 000 km): Diesel Engine Only:
Engine Air Cleaner Filter Inspection, if driving in
dusty conditions. Drive Axle Service When Towing
(2500 and 3500 Series only). Gasoline Engine Only:
Noise Shields Inspection (GVWR above 10,000 lbs.
only). Diesel Engine Only: Shields and Underhood
Insulation Inspection. Diesel Engine Only:
Thermostatically Controlled Engine Cooling Fan
Check (or every 12 months, whichever occurs first).
Diesel Engine Only: Air Intake System Inspection.
Front Wheel Bearing Repack (or at each brake
relining, whichever occurs first).
Page 346 of 411

Scheduled Maintenance
7-7
Long Trip/Highway Definition
Follow this scheduled maintenance only if none of
the conditions from the Short Trip/City Scheduled
Maintenance are true. Do not use this schedule if the
vehicle is used for trailer towing, driven in a dusty
area or used off paved roads. Use the Short Trip/City
schedule for these conditions.
Driving a vehicle with a fully warmed engine under
highway conditions will cause engine oil to break
down slower.
Long Trip/Highway Intervals
At 7,500 Miles (12 500 km): Drive Axle Service
(2500 and 3500 Series with locking differential only).
Every 7,500 Miles (12 500 km): Engine Oil and Filter
Change (or every 12 months, whichever occurs first).
Chassis Lubrication (or every 12 months, whichever
occurs first). Drive Axle Fluid Check. Tire Rotation.
Every 15,000 Miles (25 000 km): Gasoline Engine
Only: Noise Shields Inspection (GVWR above
10,000 lbs. only). Diesel Engine Only: Shields
and Underhood Insulation Inspection. Diesel Engine
Only: Thermostatically Controlled Engine Cooling
Fan Check (or every 12 months, whichever
occurs first). Diesel Engine Only: Air Intake
System Inspection.
Page 351 of 411

Short Trip/City Scheduled Maintenance
7-12
15,000 Miles (25 000 km)
Change engine oil and filter (or every 3 months, whichever occurs first).
An Emission Control Service.
Lubricate chassis components (or every 3 months, whichever occurs first).
(See footnote #.)
Diesel Engine Only: Inspect engine air cleaner filter if you are driving in
dusty conditions. Replace filter if necessary.
An Emission Control Service. (See footnote .)
Gasoline Engine Only: See ªEngine Air Cleaner Filter Restriction Indicator
Checkº in the Index.
Check axle fluid level and add fluid as needed. 2500 and 3500 Series Only:
If driving in dusty areas or when towing a trailer, drain fluid and refill every
15,000 miles (25 000 km).
Clean and repack the front wheel bearings (or at each brake relining,
whichever occurs first).
Vehicles With GVWR Above 10,000 lbs. or Equipped with Diesel Engine
Only: Inspect shields for damage or looseness. Adjust or replace as required.
This is a Noise Emission Control Service. Applicable only to vehicles sold
in the United States.ACTUAL
SERVICED BY:MILEAGE
DATE
Page 354 of 411
Short Trip/City Scheduled Maintenance
7-15
27,000 Miles (45 000 km)
Change engine oil and filter (or every 3 months, whichever occurs first).
An Emission Control Service.
Lubricate chassis components (or every 3 months, whichever occurs first).
(See footnote #.)
Check axle fluid level and add fluid as needed.
30,000 Miles (50 000 km)
Change engine oil and filter (or every 3 months, whichever occurs first).
An Emission Control Service.
Lubricate chassis components (or every 3 months, whichever occurs first).
(See footnote #.)
Check axle fluid level and add fluid as needed. 2500 and 3500 Series Only:
If driving in dusty areas or when towing a trailer, drain fluid and refill every
15,000 miles (25 000 km).
Clean and repack the front wheel bearings (or at each brake relining,
whichever occurs first).
Replace fuel filter. An Emission Control Service. (See footnote .)
(Continued)
ACTUAL
SERVICED BY:MILEAGE
DATE
ACTUAL
SERVICED BY:MILEAGE
DATE