2008 JEEP WRANGLER maintenance

Follow the recommended tire rotation frequency for your
type of driving. Refer to the “Maintenance Schedule” in
Section 8 of this manual. More frequent rotation is
permissible if desired. The reasons for any rapid or
unusual wear should be corrected prior to rotation being
performed.
The suggested rotation method is the “forward-cross”
shown in the following diagram.TIRE PRESSURE MONITOR SYSTEM (TPMS)
The Tire Pressure Monitoring System (TPMS) will warn
the driver of a low tire pressure based on the vehicle
recommended cold placard pressure.
The tire pressure will vary with temperature by about 1
psi (6.9 kPa) for every 12°F (6.5°C). This means that when
the outside temperature decreases, the tire pressure will
decrease. Tire pressure should always be set based on
cold inflation tire pressure. This is defined as the tire
pressure after a vehicle has not been driven for more than
three hours, or driven less than 1 mi (1 km) after a three
hour period.Refer to the “Tires — General Informa-
tion” in this section for information on how to properly
inflate the vehicle’s tires. The tire pressure will also
increase as the vehicle is driven, this is normal and there
should be no adjustment for this increased pressure.
330 STARTING AND OPERATING

CAUTION!
The TPMS has been optimized for the original
equipment tires and wheels. TPMS pressures have
been established for the tire size equipped on your
vehicle. Undesirable system operation or sensor
damage may result when using replacement equip-
ment that is not of the same size, type, and/or style.
Aftermarket wheels can cause sensor damage. Do not
use aftermarket tire sealants or balance beads if your
vehicle is equipped with a TPMS, as damage to the
sensors may result.
CAUTION!
After inspecting or adjusting the tire pressure always
reinstall the valve stem cap. This will prevent mois-
ture and dirt from entering the valve stem, which
could damage the Tire Pressure Monitoring Sensor.
NOTE:
•The TPMS is not intended to replace normal tire care
and maintenance, nor to provide warning of a tire
failure or condition.
•The TPMS should not be used as a tire pressure gauge
while adjusting your tire pressure.
•Driving on a significantly under-inflated tire causes
the tire to overheat and can lead to tire failure.
Under-inflation also reduces fuel efficiency and tire
tread life, and may affect the vehicle’s handling and
stopping ability.
332 STARTING AND OPERATING

NOTE:Remember that everything put into or on the
trailer adds to the load on your vehicle. Also, additional
factory-installed options, or authorized dealer-installed
options, must be considered as part of the total load on
your vehicle. Refer to the Tire and Loading Information
placard in the “Tire Safety Information” section of this
manual for the maximum combined weight of occupants
and cargo for your vehicle.
Towing Requirements
To promote proper break-in of your new vehicle driv-
etrain components, the following guidelines are recom-
mended:
NOTE: Trailer towing requires special rear axle lubri-
cant. Refer to “Fluids, Lubricants, and Genuine Parts” in
Section 7 for more information.
CAUTION!
•Avoid towing a trailer for the first 500 mi (805 km)
of vehicle operation. Doing so may damage your
vehicle.
Perform the maintenance listed in the “Maintenance
Schedule.” Refer to Section 8 of this manual. When
towing a trailer, never exceed the GAWR, or GCWR,
ratings.
STARTING AND OPERATING 353
5

Towing Tips — Cooling System
To reduce potential for engine and transmission over-
heating, take the following actions:
Highway Driving
Reduce speed.
Air Conditioning
Turn off temporarily.
refer to Cooling System Operating information in the
Maintenance section of this manual for more informa-
tion.
RECREATIONAL TOWING (BEHIND
MOTORHOME, ETC.)
CAUTION!
Front or rear wheel lifts should not be used. Internal
damage to the transmission or transfer case will occur
if a front or rear wheel lift is used when recreational
towing.
Towing – 2WD Models
Recreational towing is allowed ONLY if the rear drive-
shaft is removed. See your authorized dealer or refer to
the Service Manual. Towing with the rear wheels on the
ground while the driveshaft is connected can result in
severe transmission damage.
STARTING AND OPERATING 359
5

MAINTAINING YOUR VEHICLE
CONTENTS
Engine Compartment – 3.8L ...............378
 Onboard Diagnostic System — OBD II ........379
▫ Loose Fuel Filler Cap Message ............380
 Emissions Inspection And Maintenance
Programs ............................380
 Replacement Parts ......................382
 Authorized Dealer Service ................382
 Maintenance Procedures ..................383
▫ Engine Oil ..........................383 ▫
Drive Belts — Check Condition And Tension . . 386
▫ Spark Plugs .........................386
▫ Catalytic Converter ....................386
▫ Crankcase Emission Control System ........388
▫ Fuel Filter ..........................388
▫ Engine Air Cleaner Filter ................389
▫ Maintenance-Free Battery ................389
▫ Air Conditioner Maintenance .............390
▫ Power Steering Fluid Check ..............391
7

▫Driveline And Steering Component
Lubrication ..........................392
▫ Body Lubrication .....................392
▫ Windshield Wiper Blades ................392
▫ Windshield And Rear Window Washers .....393
▫ Exhaust System ......................393
▫ Cooling System .......................394
▫ Hoses And Vacuum/Vapor Harnesses .......399
▫ Brake System ........................399
▫ Automatic Transmission ................401
▫ Hydraulic Clutch Fluid — Manual
Transmission ........................403
▫ Manual Transmission ..................403
▫ Transfer Case ........................404 ▫
Front/Rear Axle Fluid ..................405
▫ Maintenance After Off-Road Driving ........405
▫ Appearance Care And Protection From
Corrosion ...........................406
 Fuses (Totally Integrated Power Module) ......413
 Vehicle Storage ........................419
 Replacement Bulbs — If Equipped ...........420
 Bulb Replacement ......................420
▫ Head Light ..........................420
▫ Front Park/Turn Signal .................421
▫ Front Side Marker .....................422
▫ Front Fog Light ......................422
▫ Rear Tail, Stop, Turn Signal, And Backup
Lights .............................422
376 MAINTAINING YOUR VEHICLE

Loose Fuel Filler Cap Message
After fuel is added, the vehicle diagnostic system can
determine if the fuel filler cap is possibly loose, improp-
erly installed, or damaged. A “gASCAP” message will be
displayed in the odometer. Tighten the gas cap until a
clickingsound is heard. This is an indication that the
gas cap is properly tightened. Press the odometer reset
button to turn the message off. If the problem persists,
the message will appear the next time the vehicle is
started. This might indicate a damaged cap. If the prob-
lem is detected twice in a row, the system will turn on the
“Malfunction Indicator Light.” Resolving the problem
will turn the “Malfunction Indicator Light.” off.
EMISSIONS INSPECTION AND MAINTENANCE
PROGRAMS
In some localities, it may be a legal requirement to pass
an inspection of your vehicle’s emissions control system.
Failure to pass could prevent vehicle registration.
For states that require an Inspection and Mainte-
nance (I/M), this check verifies the Malfunction
Indicator Light (MIL) is functioning and is not on
when the engine is running, and that the OBD II system
is ready for testing.
Normally, the OBD II system will be ready. The OBD II
system may notbe ready if your vehicle was recently
serviced, recently had a dead battery, or a battery replace-
ment. If the OBD II system should be determined not
ready for the I/M test, your vehicle may fail the test.
380 MAINTAINING YOUR VEHICLE

serviced before going to the I/M station. The I/M station
can fail your vehicle because the MIL is on with the
engine running.
REPLACEMENT PARTS
Use of genuine MOPARparts for normal/scheduled
maintenance and repairs is highly recommended to en-
sure the designed performance. Damage or failures
caused by the use of non-MOPAR parts for maintenance
and repairs will not be covered by the manufacturer’s
warranty.
AUTHORIZED DEALER SERVICE
Your authorized dealer has the qualified service person-
nel, special tools, and equipment to perform all service
operations in an expert manner. Service manuals are
available which include detailed service information for
your vehicle. Refer to these Service manuals before
attempting any procedure yourself. NOTE:
Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
WARNING!
You can be badly injured working on or around a
motor vehicle. Only do service work for which you
have the knowledge and the proper equipment. If
you have any doubt about your ability to perform a
service job, take your vehicle to a competent
mechanic.
382 MAINTAINING YOUR VEHICLE