2008 DODGE RAM 3500 GAS fuel

Gross Axle Weight Rating (GAWR)
The GAWR is the maximum permissible load on the front
and rear axles. The load must be distributed in the cargo
area so that the GAWR of each axle is not exceeded.
Each axle GAWR is determined by the components in the
system with the lowest load carrying capacity (axle,
springs, tires or wheels). Heavier axles or suspension
components sometimes specified by purchasers for in-
creased durability does not necessarily increase the vehi-
cle's GVWR.
Tire Size
The tire size on the Label represents the actual tire size on
your vehicle. Replacement tires must be equal to the load
capacity of this tire size.
Rim Size
This is the rim size that is appropriate for the tire size
listed.
Inflation Pressure
This is the cold tire inflation pressure for your vehicle for
all loading conditions up to full GAWR.
Curb Weight
The curb weight of a vehicle is defined as the total weight
of the vehicle with all fluids, including vehicle fuel, at full
capacity conditions, and with no occupants or cargo
loaded into the vehicle. The front and rear curb weight
values are determined by weighing your vehicle on a
commercial scale before any occupants or cargo are
added.
382 STARTING AND OPERATING

NOTE:Using the ªTOW HAULº or ªOD/OFFº range
while operating the vehicle under heavy operating con-
ditions will improve performance and extend transmis-
sion life by reducing excessive shifting and heat build up.
This action will also provide better engine braking.
The automatic transmission fluid and filter should be
changed if you REGULARLY tow a trailer for more than
45 minutes of continuous operation. See Maintenance
Schedule in section 8 of this manual for transmission
fluid change intervals.
NOTE:Check the automatic transmission fluid level
before towing.
Towing Tips Ð Tow/Haul (If Equipped)
To reduce potential for automatic transmission overheat-
ing, turn the ªTOW HAUL OD/OFFº feature ON when
driving in hilly areas or shift the transmission to Drive
position 2 on more severe grades.
Towing Tips Ð Electronic Speed Control (If
Equipped)
þ
Don't use in hilly terrain or with heavy loads.
þWhen using the speed control, if you experience speed
drops greater than 10 mph (16 km/h), disengage until
you can get back to cruising speed.
þUse speed control in flat terrain and with light loads to
maximize fuel efficiency.
Towing Tips Ð Cooling System
To reduce potential for engine and transmission over-
heating, take the following actions:
þCity Driving
When stopped for short periods of time, put transmission
in neutral and increase engine idle speed.
þHighway Driving
Reduce speed.
STARTING AND OPERATING 399
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MAINTAINING YOUR VEHICLE
CONTENTS
mEngine CompartmentÐ 3.7L...............444
mEngine CompartmentÐ 4.7L...............445
mEngine CompartmentÐ 5.7L...............446
mOnboard Diagnostic System (OBD II).........447
NLoose Fuel Filler Cap Message............447
mEmissions Inspection And Maintenance
Programs............................448
mReplacement Parts......................449
mAuthorized Dealer Service................450mMaintenance Procedures..................450
NEngine Oil..........................451
NEngine Oil Filter......................454
NDrive Belts Ð Check Condition And Tension . . 454
NSpark Plugs (Gas Engines)...............454
NEngine Air Cleaner Filter................455
NEngine Fuel Filter.....................455
NCatalytic Converter....................455
NEmission-Related Components............457
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NMaintenance-Free Battery................457
NAir Conditioner Maintenance.............459
NPower Steering Ð Fluid Check............460
NFront Suspension Ball Joints..............460
NSteering Linkage Ð Inspection............461
NHalf-Shaft Constant Velocity Joints.........461
NFront Prop Shaft Lubrication Ð
2500/3500 (4X4) Models................462
NBody Lubrication.....................462
NWindshield Wiper Blades................463
NWindshield Washers...................463
NExhaust System......................464NCooling System.......................465
NHoses And Vacuum/Vapor Harnesses.......470
NFuel System Connections................471
NBrake System........................471
NClutch Hydraulic System................474
NClutch Linkage.......................474
NRear Axle And 4X4 Front Driving Axle
Fluid Level..........................474
NTransfer Case........................475
NManual Transmission..................476
NAutomatic Transmission................476
NFront And Rear Wheel Bearings...........479
442 MAINTAINING YOUR VEHICLE

ONBOARD DIAGNOSTIC SYSTEM (OBD II)
Your vehicle is equipped with a sophisticated onboard
diagnostic system called OBDII. This system monitors
the performance of the emissions, engine, and automatic
transmission control systems. When these systems are
operating properly, your vehicle will provide excellent
performance and fuel economy, as well as engine emis-
sions well within current government regulations.
If any of these systems require service, the OBD II system
will turn on the Malfunction Indicator Light (MIL). It will
also store diagnostic codes and other information to
assist your service technician in making repairs. Al-
though your vehicle will usually be drivable and not
need towing, see your authorized dealer for service as
soon as possible.CAUTION!
Prolonged driving with the Malfunction Indicator
Light (MIL) on could cause further damage to the
emission control system. It could also affect fuel
economy and drivability. The vehicle must be ser-
viced before any emissions tests can be performed.
If the Malfunction Indicator Light (MIL) is flashing,
severe catalytic converter damage and power loss
will soon occur. Immediate service is required.
Loose Fuel Filler Cap Message
If the vehicle's diagnostic system determines that the fuel
filler cap in loose, improperly installed, or damaged, a
GASCAP message will be displayed in the instrument
cluster. Tighten the gas cap until a ªclickingº sound is
heard. This is an indication that the gas cap is properly
MAINTAINING YOUR VEHICLE 447
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Change Engine Oil
Follow the Maintenance Schedule for recommended en-
gine oil change intervals.
Engine Oil Selection
For best performance and maximum protection under all
types of operating conditions, the manufacturer only
recommends engine oils that are API-certified and meet
the requirements of DaimlerChrysler Material Standard
MS-6395.
American Petroleum Institute (API) Engine Oil
Identification Symbol
This symbol means that the oil has
been certified by the American
Petroleum Institute (API). The
manufacturer only recommends
API-Certified engine oils.
Engine Oil Viscosity (SAE Grade)
SAE 5W-20 engine oil is recommended for all operating
temperatures. This engine oil improves low temperature
starting and vehicle fuel economy. The engine oil filler
cap also shows the recommended engine oil viscosity for
your engine. For information on engine oil filler cap
location, refer to the ªEngine Compartmentº illustration
in this section.
452 MAINTAINING YOUR VEHICLE

Engine Air Cleaner Filter
Follow the Maintenance Schedule for recommended En-
gine Air Cleaner Filter change intervals.
WARNING!
The air induction system (air cleaner, hoses, etc.) can
provide a measure of protection in the case of engine
backfire. Do not remove the air induction system (air
cleaner, hoses, etc.) unless such removal is necessary
for repair or maintenance. Make sure that no one is
near the engine compartment before starting the
vehicle with the air induction system (air cleaner,
hoses, etc.) removed. Failure to do so can result in
serious personal injury.
Engine Fuel Filter
A plugged fuel filter can cause stalling, limit the speed at
which a vehicle can be driven or cause hard starting.
Should an excessive amount of dirt accumulate in the
fuel tank, frequent filter replacement may be necessary.
Catalytic Converter
The catalytic converter requires the use of unleaded fuel
only. Leaded gasoline will destroy the effectiveness of the
catalyst as an emission control device.
Under normal operating conditions, the catalytic con-
verter will not require maintenance. However, it is im-
portant to keep the engine properly tuned to assure
proper catalyst operation and prevent possible catalyst
damage.
MAINTAINING YOUR VEHICLE 455
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Ensure nylon tubing in these areas has not melted or
collapsed.
Inspect all hose connections such as clamps and cou-
plings to make sure they are secure and no leaks are
present.
Components should be replaced immediately if there is
any evidence of wear or damage that could cause failure.
Fuel System Connections
Electronic Fuel Injection high pressure fuel systems are
designed with tubes and special connects, connections
and clamps which have unique material characteristics to
provide adequate sealing and resist attack by deterio-
rated gasoline.
You are urged to use only the manufacture's specified
tubes, connections and clamps, or their equivalent in
material and specification, in any fuel system servicing.
Brake System
Power Disc Brakes (Front and Rear)
Disc brakes do not require adjustment; however, several
hard stops during the break-in period are recommended
to seat the linings and wear off any foreign material.
Brake and Power Steering Hoses
When the vehicle is serviced for scheduled maintenance,
inspect surface of hoses and nylon tubing for evidence of
heat and mechanical damage. Hard and brittle rubber,
cracking, tears, cuts, abrasion, and excessive swelling
indicate deterioration of the rubber. Particular attention
should be made to examining those hose surfaces nearest
to high heat sources, such as the exhaust manifold.
Ensure nylon tubing in these areas has not melted or
collapsed.
MAINTAINING YOUR VEHICLE 471
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