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CAUTION: Do not overfill the engine crankcase with
oil. This will cause oil aeration and result in a de-
crease in the engine oil pressure.
(9) Start the engine and observe the oil pressure
gauge or warning lamp. If the pressure does not in-
crease or the warning lamp does not go out, stop the
engine and determine the cause of the problem.
USED ENGINE OIL DISPOSAL
Care should be exercised when disposing used en-
gine oil after it has been drained from a vehicle en-
gine. Refer to the WARNING listed above.
COOLING SYSTEM
WARNING: USE EXTREME CAUTION WHEN RE-
MOVING THE RADIATOR CAP IF THE ENGINE IS
OPERATING. DO NOT PUT YOUR HANDS NEAR
THE DRIVE BELT(S), PULLEYS OR FAN BLADE. DO
NOT STAND IN A DIRECT LINE WITH THE FAN
BLADE.
RECOMMENDED MAINTENANCE
The engine coolant level should be determined at
least once a month and more often during periods of
hot weather. Add coolant as necessary.
COOLANT LEVEL
With the engine at normal operating temperature,
observe the coolant level in thecoolant recovery bot-
tle. The coolant level must be at least above the ADD
mark and preferably at the FULL mark. Add coolant
to the coolant recovery bottleonly, if necessary.
REQUIRED MAINTENANCE
Check coolant level, and inspect condition of cool-
ing system hoses and clamps after each 12 000-km
(7,500-miles).
Initially, coolant must be drained and cooling sys-
tem flushed and filled after the first 36 months of op-
eration. Thereafter, after each 24-months interval of
vehicle operation.
RECOMMENDED MAINTENANCE
The engine cooling system should be inspected for
proper operation and for component failure at least
every 12 months.
WARNING: IF THE ENGINE HAS BEEN RECENTLY
OPERATED, USE EXTREME CARE WHEN REMOV-
ING THE RADIATOR CAP TO AVOID SCALDING
WITH HOT, PRESSURIZED COOLANT.
For additional information, refer to Section 7, Cool-
ing System.COOLANT FREEZE PROTECTION
Jeeptcooling systems contain a 50/50 mixture of
anti-freeze and distilled water coolant. This is the
recommended coolant mixture for most ambient tem-
peratures. The factory-installed anti-freeze is formu-
lated to prevent corrosion on all cooling system metal
surfaces.
The degree of coolant freeze protection should be
tested every 12 months. If the coolant is contami-
nated orrustyin appearance, cooling system should
be drained and filled with a 50/50 mixture of fresh
coolant. For additional information, refer to Group
7ÐCooling System.
ENGINE AIR CLEANER FILTER ELEMENT
RECOMMENDED MAINTENANCE
Engine performance and fuel economy can be af-
fected by a restricted air cleaner filter. The filter
should be inspected on a regular basis for excessive
air restriction.
If the filter element is saturated with oil, replace
the filter element.
REQUIRED MAINTENANCE
Engine air cleaner filter must be replaced after
each 48 000-km (30,000-miles).
If a vehicle is frequently operated in dusty
areas, the air cleaner filter should be inspected
often.
FILTER ELEMENT SERVICE/REPLACEMENT
(1) Remove the air cleaner cover from the body/
housing (Fig. 9).
(2) Remove the air cleaner filter element from the
body/housing.
Fig. 9 Air Cleaner & Filter ElementÐ2.5L and 4.0L
Engines
0 - 16 LUBRICATION AND MAINTENANCEJ
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CAUTION: Do not tap the filter element or immerse
the filter in liquid to remove trapped particles.
(3) Clean filter element by gently blowing the
trapped particles from the filter with compressed air.
Direct air in the opposite direction of normal intake
air flow. Keep air nozzle at least two inches away
from the filter to avoid damage to filter.
(4) If the filter has become partially saturated with
oil, replace the filter. Test the crankcase ventilating
(CCV) system for proper operation.
(5) Wash the air cleaner cover and body/housing
(Figs. 10) with cleaning solvent and wipe dry.
(6) Install the air cleaner filter element and attach
the cover to the body/housing.
CRANKCASE VENTILATION SYSTEM
All Jeept2.5L and 4.0L engines are equipped with
a crankcase ventilation (CCV) system. Refer to
Group 25ÐEmissions, for additional information.
FUEL USAGE STATEMENTÐGAS ENGINES
Jeeptvehicles are designed to meet all emission
regulations and provide excellent fuel economy using
high quality unleaded gasoline. Only use unleaded
gasolines having a minimum posted octane of 87.
If a Jeeptvehicle develops occasional light spark
knock (ping) at low engine speeds, this is not harm-
ful. However,continued heavy knock at high
speeds can cause damage and should be
checked immediately.Engine damage as a result of
heavy knock operation may not be covered by the
new vehicle warranty.In addition to using unleaded gasoline with the
proper octane rating,those that contain deter-
gents, corrosion and stability additives are rec-
ommended.Using gasolines that have these
additives will help improve fuel economy, reduce
emissions and maintain vehicle performance. Gener-
ally, premium unleaded gasolines contain more addi-
tive than regular unleaded gasolines.
Poor quality gasolinecan cause problems such as
hard starting, stalling and stumble. If these problems
occur, use another brand of gasoline before consider-
ing servicing the vehicle.
GASOLINE/OXYGENATE BLENDS
Some fuel suppliers blend unleaded gasoline with
materials that contain oxygen such as alcohol, MTBE
and ETBE. The type and amount of oxygenate used
in the blend is important. The following are gener-
ally used in gasoline blends:
ETHANOL
Ethanol (Ethyl or Grain Alcohol) properly blended,
is used as a mixture of 10 percent ethanol and 90
percent gasoline.Gasoline with ethanol may be
used in your vehicle.
METHANOL
CAUTION: Do not use gasolines containing metha-
nol. Use of methanol/gasoline blends may result in
starting and driveability problems. In addition, dam-
age may be done to critical fuel system compo-
nents.
Methanol (Methyl or Wood Alcohol) is used in a va-
riety of concentrations blended with unleaded gaso-
line. You may encounter fuels containing 3 percent
or more methanol along with other alcohols called co-
solvents.
Problems that are the result of using methanol/gas-
oline blends are not the responsibility of Chrysler
Corporation. They may not be covered by the vehicle
warranty.
MTBE/ETBE
Gasoline and MTBE (Methyl Tertiary Butyl Ether)
blends are a mixture of unleaded gasoline and up to
15 percent MTBE. Gasoline and ETBE (Ethyl Ter-
tiary Butyl Ether) are blends of gasoline and up to
17 percent ETBE. Gasoline blended with MTBE or
ETBE may be used.
CLEAN AIR GASOLINE
Many gasolines are now being blended that con-
tribute to cleaner air, especially in those areas of the
country where air pollution levels are high. These
new blends provide a cleaner burning fuel and some
are referred to asReformulated Gasoline.
Fig. 10 Air Cleaner Body/Housing & Cover
JLUBRICATION AND MAINTENANCE 0 - 17
Page 19 of 1784

In areas of the country where carbon monoxide lev-
els are high, gasolines are being treated with oxy-
genated materials such as MTBE, ETBE and
ethanol.
Chrysler Corporation supports these efforts toward
cleaner air and recommends the use of these gaso-
lines as they become available.
IGNITION CABLES, DISTRIBUTOR CAP AND
ROTOR
REQUIRED IGNITION SYSTEM MAINTENANCE
The ignition cables, distributor cap and rotor must
be replaced after each 96 000-km (60,000-miles). Re-
fer to Group 8DÐIgnition Systems for additional in-
formation.
IGNITION TIMING
The ignition timing for 2.5L and 4.0L engines is
not adjustable. Refer to the specifications listed on
the engine Emission Control Information Label. Re-
fer to Group 25ÐEmission Control Systems for addi-
tional information.
SPARK PLUGS
REQUIRED MAINTENANCE
The spark plugs must be replaced after each 48
000-km (30,000-miles). Refer to the Spark Plugs
chart below and to Group 8DÐIgnition Systems for
additional information.
BATTERY
RECOMMENDED MAINTENANCE
The battery electrolyte level should be checked and
the cable clamps should be inspected for corrosion.
This should be done when the oil is changed and the
oil filter is replaced.
The battery cables should be inspected for abnor-
mal clamp and battery terminal post corrosion. Ser-
vice the terminals and cable clamps as necessary.In addition, the general condition of the battery
should be determined before the start of cold and hot
weather seasons. If the battery condition is marginal
or worse, it should be replaced.
Care should be taken when disposing a bat-
tery after removal from a vehicle. Lead-acid bat-
teries are highly poisonous and, when
indiscriminately disposed, could create a prob-
lem for the environment. Contact the applicable
local city or county government agency to deter-
mine where automobile (lead-acid) batteries can
be properly disposed in the local area.
INSPECTION/SERVICE
WARNING: WEAR SAFETY GLASSES, RUBBER
GLOVES AND PROTECTIVE CLOTHING WHEN HAN-
DLING/SERVICING A BATTERY. THE BATTERY
ELECTROLYTE CONTAINS SULFURIC ACID AND
WILL CAUSE HARM IF IT CONTACTS SKIN, EYES
OR CLOTHING. IT WILL ALSO DAMAGE PAINTED
(AS WELL AS UN-PAINTED) SURFACES OF A VEHI-
CLE. IF SULFURIC ACID CONTACTS ANY OF
THESE, FLUSH IMMEDIATELY WITH LARGE
AMOUNTS OF WATER. IF SULFURIC ACID CON-
TACTS SKIN OR EYES, GET IMMEDIATE MEDICAL
ATTENTION. DO NOT SMOKE IN THE VICINITY OF
A BATTERY. KEEP OPEN FLAMES AND SPARKS
AWAY FROM BATTERY FILLER CAPS BECAUSE
EXPLOSIVE GAS IS ALWAYS PRESENT.
(1) Disconnect the battery negative cable and then
the positive cable.
(2) Clean the battery cable clamps and terminal
posts with a wire brush and a battery terminal
cleaner.
(3) Pry the battery cell filler caps upward to re-
move them and inspect each filler well (low-mainte-
nance batteries only, not applicable to maintenance-
free batteries). It could possibly be necessary to
loosen the battery holddown clamp to remove the
caps. Maintain the electrolyte level above the battery
plates and at the bottom of the filler well ring. Add
distilled water or low-mineral content drinking wa-
ter, if necessary. In freezing weather (below 0ÉC/
32ÉF), add the water just before driving to ensure
that it mixes thoroughly with the electrolyte. This
will prevent it from freezing.
(4) Remove the battery holddown strap and clean
the battery case/battery tray.Clean with bicarbonate
of soda (baking soda) and water. Rinse and dry the
battery case/tray thoroughly after cleaning.
(5) Position the battery in the tray and install the
holddown strap.Do not over-tighten the nuts.
(6) Connect the battery positive cable and then the
negative cable to the battery.
SPARK PLUGS
0 - 18 LUBRICATION AND MAINTENANCEJ
Page 20 of 1784

(7) Apply a small amount of chassis lubricant (or
an equivalent protective coating) to the cable termi-
nals to minimize corrosion.
RUBBER AND PLASTIC DUCTS/HOSES/TUBING
RECOMMENDED MAINTENANCE
Rubber and plastic ducts/hoses/tubing should be in-
spected at the same time the engine oil is changed
and the oil filter is replaced.
The conditions associated with vehicle operation
determines the usable life of the rubber and plastic
ducts/hoses/tubing. These conditions include:
²the extent and quality of vehicle maintenance,
²the geographic area of vehicle operation, and
²the length of exposure time to excess heat and
chemical contaminants.
DUCT/HOSE/TUBING INSPECTIONÐEXCEPT
EMISSION CONTROL HOSES/TUBING
Refer to Group 25ÐEmission Control Systems.
Engine performance could be affected by air leaks
into various hoses.
Rubber/plastic ducts, hoses and tubing should
be replaced immediately if there is any evidence
of deterioration.
(1) Inspect all hose fittings for looseness and corro-
sion. Inspect rubber ducts (Fig. 12) and hoses for
brittleness and cracks. Examine the hose ends (those
that are slipped over nipple connectors) for splits.
(2) Inspect surface of hoses and tubing (Fig. 13) for
heat and mechanical damage.The hose and tubing
that is located near an exhaust manifold should
be given special attention.
(3) Inspect the rubber hose routing to ensure that
the hoses do not contact any heat source, moving
component, etc., that could potentially cause heat or
mechanical damage (Figs. 14, 15, and 16).
(4) Inspect all the hose connections to ensure that
they are secure and that there is no fluid leakage. Inmany instances, liquid lubricants are used to aid in
the connection of hoses to couplings.
Fig. 12 Intake Air Duct (XJ)ÐTypical
Fig. 13 Washer Fluid TubingÐTypical
Fig. 14 ATF Cooler Hoses ÐXJ Vehicles
Fig. 11 Brake Booster Vacuum Hose (XJ)ÐTypical
JLUBRICATION AND MAINTENANCE 0 - 19
Page 21 of 1784

ENGINE SUPPORTS
RECOMMENDED MAINTENANCE
The general condition of the engine supports
should be inspected at the same time as the engine
oil is changed and the oil filter is replaced.
INSPECTION
(1) Test the hardware that attaches the engine cyl-
inder block to the engine support brackets (Figs. 17
and 18) for the specified tightening torque.
(2) Inspect the rubber in the engine support cush-
ions for softening and swelling. Slight surface deteri-
oration and wear at the ends will not affect the
functioning of an engine support.
ACCESSORY DRIVE BELT
RECOMMENDED MAINTENANCE
The accessory drive belt should be inspected for
cracks, fraying, and excessive wear. If necessary, re-
fer to Group 7ÐCooling Systems for replacement pro-
cedures and adjustment specifications.
REQUIRED MAINTENANCE
The drive belt must be adjusted after each 48
000-km (30,000-miles) interval of vehicle operation
has elapsed. The accessory drive belt must be re-
placed after each 96 000-km (60,000-miles). If neces-
sary, refer to Group 7ÐCooling Systems.
EXHAUST SYSTEM
REQUIRED MAINTENANCE
The general condition of the exhaust system must
be inspected after each 12 000-km (7,500-miles).
An exhaust system must be properly aligned to
prevent stress, leakage, and vehicle body contact.
Fig. 17 Front Engine SupportÐTypical
Fig. 18 Rear Engine SupportÐTypical
Fig. 15 ATF Cooler Hoses ÐXJ Vehicles
Fig. 16 ATF Cooler Hoses (4.0L)ÐYJ Vehicles
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Page 22 of 1784

INSPECTION
When inspecting an exhaust system, inspect for
cracked or loose joints, stripped screw/bolt threads,
corrosion damage, and worn or broken hangers. Re-
place all components that are corroded or damaged.
Do not attempt repair. Also, inspect for the following
obvious conditions and correct as necessary:
²exhaust system leaks, damage, misalignment;
²contact with body panels metal or the frame; and
²catalytic converter bulging or excessive heat dam-
age.
CAUTION: A catalytic converter will become con-
taminated if leaded gasoline is burned in the en-
gine. If this occurs, the complete converter must be
replaced.
AIR-CONDITIONER COMPRESSOR/HOSES/
FITTINGS
RECOMMENDED MAINTENANCE
The general condition of the A/C compressor, hoses
and fittings should be inspected at the same time as
the engine oil is changed (Figs. 19, 20 and 21).
LUBRICANT AND REFRIGERANT
In addition to inspection, the lubricant level in the
compressor (Fig. 22) should be determined if there
are indications that oil was lost.
Loss of lubricating oil usually accompanies a loss of
refrigerant. The presence of bubbles/white foam
within the receiver/drier sight glass indicates that
some loss of refrigerant has occurred.
For additional information involving the A/C sys-
tem, refer to Group 24ÐHeater And Air Conditioning.
Fig. 19 A/C System (XJ)Ð2.5L Engine
Fig. 20 A/C System (XJ)Ð4.0L Engine
Fig. 21 A/C System (YJ)Ð4.0L Engine
Fig. 22 A/C CompressorÐTypical
JLUBRICATION AND MAINTENANCE 0 - 21
Page 23 of 1784

DRIVETRAIN
INDEX
page page
Automatic Transmission.................... 23
Drive Shafts............................ 27
Front and Rear Axles..................... 26
Hydraulic Clutch......................... 22Manual Transmission...................... 22
Rubber and Plastic Hoses/Tubing............ 28
Transfer Case........................... 25
HYDRAULIC CLUTCH
RECOMMENDED MAINTENANCE
Check fluid level in the hydraulic clutch master
cylinder reservoir (Fig. 1) at the same time engine
oil is changed and oil filter is replaced. Add fluid as
necessary.
FLUID SPECIFICATION
The only fluid recommended for use in a hydraulic
clutch system is MOPAR Brake And Hydraulic
Clutch Fluid., or an equivalent fluid.
CAUTION: Never use reclaimed brake fluid or fluid
from an unsealed container. In addition, do not use
fluid from a container that has been opened and al-
lowed to stand for an extended length of time.
Moisture in the air can be absorbed by the fluid,
which causes dilution with loss of effectiveness.
FLUID LEVEL
Remove the master cylinder fluid reservoir cap
(Fig. 2). The fluid level is determined by its height inrelation to the level indicator ring (Fig. 3) located in-
side the reservoir. If necessary, add fluid until the
height is level with the indicator ring.
MANUAL TRANSMISSION
RECOMMENDED MAINTENANCE
The lube oil level in manual transmissions should
be determined at the same time as the engine oil is
changed and the oil filter is replaced. Add lube oil as
necessary.
Fig. 1 Hydraulic Clutch (YJ)ÐTypical
Fig. 2 Hydraulic Clutch Master Cylinder Fluid
Reservoir
Fig. 3 Hydraulic Clutch Fluid Level
0 - 22 LUBRICATION AND MAINTENANCEJ
Page 24 of 1784

Under normal driving conditions, manual trans-
mission lube oil should be changed after each 60
000-km (37,500 miles). With severe driving condi-
tions, after each 29 000-km (18,000 miles).
LUBRICANT SPECIFICATION
When it becomes necessary to add to or change the
lube oil in a Jeeptmanual transmission, use SAE
75W-90, API Quality Grade GL-5 gear lubricant.
LUBRICANT LEVEL
The fill-hole plug for all manual transmissions is
located on the right side of the case (Fig. 4). Deter-
mine the lubricant level according to the following
procedure.
(1) Remove the fill-hole plug (Fig. 4) from the
transmission. The lube oil should be level with the
bottom edge of the fill hole. The level can be slightly
below the bottom edge of the fill hole if the lube oil
is cold.
If the transmission is warm, lube oil could drip
out of the fill hole. This is acceptable but the
lube oil should not gush out of the fill hole.
(2) If not acceptable, raise the lube oil level to the
bottom edge of the transmission fill hole. Use SAE
75W-90, API Quality Grade GL-5 gear lubricant.
Add lube oil in small amounts to raise the
level.
(3) Install the fill-hole plug in the transmission.
Tighten the plug with 37 NIm (27 ft. lbs.) torque.
LUBE OIL CHANGE
When it becomes necessary to change manual
transmission lube oil, use the following procedure.
(1) Raise and support the vehicle.
(2) Remove the fill-hole plug from the transmis-
sion.
(3) Place a container to collect the lube oil under
the transmission drain-hole plug.(4) Remove the drain-hole plug and drain the lube
oil from the transmission into the container.
Care should be exercised when disposing used
lube oil after it has been drained from a trans-
mission.
(5) Install the drain-hole plug in the transmission.
Tighten the plug with 37 NIm (27 ft. lbs.) torque.
(6) Fill the transmission until the lube oil begins
to drip out of the fill hole with SAE 75W-90, API
Quality Grade GL-5 gear lubricant.
(7) Install the fill-hole plug in the transmission.
Tighten the plug with 37 NIm (27 ft. lbs.) torque.
(8) Remove the support and lower the vehicle.
AUTOMATIC TRANSMISSION
RECOMMENDED MAINTENANCE
Check fluid level in automatic transmissions (Fig.
5) the same time the engine oil is changed and the
oil filter is replaced. Add ATF as necessary.
Under normal driving conditions, the ATF should
be changed and the filter replaced after each 48
000-km (30,000-miles). With severe driving condi-
tions, after each 29 000-km (12,000-miles).
ATF SPECIFICATIONS
When it becomes necessary to add fluid (ATF) to a
Jeeptautomatic transmission (or when the ATF is
replaced), use:
²MerconŸ ATFonlyfor AW-4 automatic transmis-
sions (XJ vehicles), and
²MOPAR ATF PLUS type 7176 (or an equivalent
MerconŸ/Dexron IIŸ ATF) for 998 automatic trans-
missions (YJ vehicles).
SPECIAL ADDITIVES
The addition of any special-type fluid to a Jeept
automatic transmission is not recommended. The
only exception is the addition of black-light detection
Fig. 5 AW-4 Automatic Transmission (XJ)
Fig. 4 Manual Transmission Fill- & Drain-Hole
PlugsÐTypical
JLUBRICATION AND MAINTENANCE 0 - 23