2002 JEEP GRAND CHEROKEE Starting system

LUBRICATION & MAINTENANCE
TABLE OF CONTENTS
page page
LUBRICATION & MAINTENANCE
SPECIFICATIONS - FLUID CAPACITIES.......1
INTERNATIONAL SYMBOLS
DESCRIPTION..........................2
PARTS & LUBRICANT RECOMMENDATION
STANDARD PROCEDURE - PARTS &
LUBRICANT RECOMMENDATIONS.........2
FLUID TYPES
DESCRIPTION
DESCRIPTION - ENGINE COOLANT........2
DESCRIPTION - ENGINE COOLANT........3
ENGINE OIL..........................4
DESCRIPTION - ENGINE OIL.............4
DESCRIPTION........................5
DESCRIPTION - TRANSFER CASE - NV242 . . 5
DESCRIPTION - TRANSFER CASE - NV247 . . 5
DESCRIPTION - AUTOMATIC
TRANSMISSION FLUID..................5
DESCRIPTION - ENGINE OIL - DIESEL
ENGINES............................6OPERATION - AUTOMATIC TRANSMISSION
FLUID...............................6
FLUID FILL/CHECK LOCATIONS
INSPECTION - FLUID FILL/CHECK
LOCATIONS..........................6
MAINTENANCE SCHEDULES
DESCRIPTION..........................6
LIFT POINTS
STANDARD PROCEDURE - HOISTING AND
JACKING RECOMMENDATIONS...........6
JUMP STARTING
STANDARD PROCEDURE - JUMP STARTING . . 7
EMERGENCY TOW HOOKS
DESCRIPTION..........................8
TOWING
STANDARD PROCEDURE - TOWING
RECOMMENDATIONS...................8
LUBRICATION &
MAINTENANCE
SPECIFICATIONS - FLUID CAPACITIES
DESCRIPTION SPECIFICATION
FUEL TANK 20 U.S. Gallons (76
Liters)****
Engine Oil - with Filter -
2.7L Diesel6.5L (6.9 qts.)
Engine Oil - with Filter -
4.0L5.7 L (6.0 qts.)
Engine Oil - with Filter -
4.7L5.7 L (6.0 qts.)
Cooling System - 2.7L
Diesel14.2L (15 qts.)***
Cooling System - 4.0L 14.1 L (15 qts.)***
Cooling System - 4.7L 13.7 L (14.5 qts.)***
AUTOMATIC TRANSMISSION
Service Fill - 42RE 3.8 L (4.0 qts.)
Service Fill - 545RFE 2WD - 5.2 L (11 pts.)
4WD - 6.2 L (13 pts.)
O-haul Fill - 42RE 9.1-9.5 L (19-20 pts.)
DESCRIPTION SPECIFICATION
O-haul Fill - 545RFE 13.33 L (28.0 pts.)
Dry fill capacity Depending on type and size of internal
cooler, length and inside diameter of cooler lines, or use
of an auxiliary cooler, these figures may vary. (Refer to
appropriate 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC/FLUID - STANDARD PROCEDURE).
TRANSFER CASE
NV242 1.35L (2.85 pts.)
NV247 1.6L (3.4 pts.)
FRONT AXLE   0.3 L (1 oz.)
186 FBI (Model 30) 1.18 L (2.5 pts.)*
* With Vari-Lok add 0.07 L (2.5 oz.) of Friction Modifier.
REAR AXLE   0.3 L (1 oz.)
198 RBI (Model 35) 1.66 L (3.5 pts.)*
226 RBA (Model 44) 2.24 L (4.75 pts.)**
* With Trac-lok add 0.07 L (2.5 oz.) of Friction Modifier.
** With Trac-lok or Vari-Lok, add 0.07 L (2.5 oz.) of
Friction Modifier.
*** Includes 0.9L (1.0 qts.) for coolant reservoir.
****Nominal refill capacities are shown. A variation may
be observed from vehicle to vehicle due to
manufacturing tolerance and refill procedure.
WJLUBRICATION & MAINTENANCE 0 - 1

JUMP STARTING
STANDARD PROCEDURE - JUMP STARTING
WARNING: REVIEW ALL SAFETY PRECAUTIONS
AND WARNINGS IN GROUP 8A, BATTERY/START-
ING/CHARGING SYSTEMS DIAGNOSTICS. DO NOT
JUMP START A FROZEN BATTERY, PERSONAL
INJURY CAN RESULT. DO NOT JUMP START WHEN
MAINTENANCE FREE BATTERY INDICATOR DOT IS
YELLOW OR BRIGHT COLOR. DO NOT JUMP
START A VEHICLE WHEN THE BATTERY FLUID IS
BELOW THE TOP OF LEAD PLATES. DO NOT
ALLOW JUMPER CABLE CLAMPS TO TOUCH
EACH OTHER WHEN CONNECTED TO A BOOSTER
SOURCE. DO NOT USE OPEN FLAME NEAR BAT-
TERY. REMOVE METALLIC JEWELRY WORN ON
HANDS OR WRISTS TO AVOID INJURY BY ACCI-
DENTAL ARCING OF BATTERY CURRENT. WHEN
USING A HIGH OUTPUT BOOSTING DEVICE, DO
NOT ALLOW BATTERY VOLTAGE TO EXCEED 16
VOLTS. REFER TO INSTRUCTIONS PROVIDED
WITH DEVICE BEING USED.
CAUTION: When using another vehicle as a
booster, do not allow vehicles to touch. Electrical
systems can be damaged on either vehicle.
TO JUMP START A DISABLED VEHICLE:
(1) Raise hood on disabled vehicle and visually
inspect engine compartment for:
²Battery cable clamp condition, clean if necessary.
²Frozen battery.
²Yellow or bright color test indicator, if equipped.
²Low battery fluid level.
²Generator drive belt condition and tension.
²Fuel fumes or leakage, correct if necessary.
CAUTION: If the cause of starting problem on dis-
abled vehicle is severe, damage to booster vehicle
charging system can result.
(2) When using another vehicle as a booster
source, park the booster vehicle within cable reach.
Turn off all accessories, set the parking brake, place
the automatic transmission in PARK or the manual
transmission in NEUTRAL and turn the ignition
OFF.
(3) On disabled vehicle, place gear selector in park
or neutral and set park brake. Turn off all accesso-
ries.
(4) Connect jumper cables to booster battery. RED
clamp to positive terminal (+). BLACK clamp to neg-
ative terminal (-). DO NOT allow clamps at opposite
end of cables to touch, electrical arc will result.
Review all warnings in this procedure.
(5) On disabled vehicle, connect RED jumper cable
clamp to positive (+) terminal. Connect BLACK
jumper cable clamp to engine ground as close to the
ground cable attaching point as possible (Fig. 8).
(6) Start the engine in the vehicle which has the
booster battery, let the engine idle a few minutes,
then start the engine in the vehicle with the dis-
charged battery.
CAUTION: Do not crank starter motor on disabled
vehicle for more than 15 seconds, starter will over-
heat and could fail.
(7) Allow battery in disabled vehicle to charge to
at least 12.4 volts (75% charge) before attempting to
start engine. If engine does not start within 15 sec-
onds, stop cranking engine and allow starter to cool
(15 min.), before cranking again.
Fig. 7 Correct Vehicle Lifting Locations
WJLUBRICATION & MAINTENANCE 0 - 7
LIFT POINTS (Continued)

DISCONNECT CABLE CLAMPS AS FOLLOWS:
²Disconnect BLACK cable clamp from engine
ground on disabled vehicle.
²When using a Booster vehicle, disconnect
BLACK cable clamp from battery negative terminal.
Disconnect RED cable clamp from battery positive
terminal.
²Disconnect RED cable clamp from battery posi-
tive terminal on disabled vehicle.
EMERGENCY TOW HOOKS
DESCRIPTION
WARNING: REMAIN AT A SAFE DISTANCE FROM A
VEHICLE THAT IS BEING TOWED VIA ITS TOW
HOOKS. THE TOW STRAPS/CHAINS COULD BREAK
AND CAUSE SERIOUS INJURY.
Some Jeep vehicles are equipped with front emer-
gency tow hooks (Fig. 9). The tow hooks should be
used forEMERGENCYpurposes only.
CAUTION: DO NOT use emergency tow hooks for
tow truck hook-up or highway towing.
TOWING
STANDARD PROCEDURE - TOWING
RECOMMENDATIONS
A vehicle equipped with SAE approved wheel lift-
type towing equipment can be used to tow WJ vehi-
cles. When towing a 4WD vehicle using a wheel-lift
towing device, use tow dollies under the opposite end
of the vehicle. A vehicle with flatbed device can also
be used to transport a disabled vehicle (Fig. 10).
SAFETY PRECAUTIONS
CAUTION: The following safety precautions must be
observed when towing a vehicle:
²Secure loose and protruding parts.
²Always use a safety chain system that is inde-
pendent of the lifting and towing equipment.
Fig. 8 Jumper Cable Clamp Connections
1 - ENGINE GROUND
2 - NEGATIVE JUMPER CABLE
3 - BATTERY NEGATIVE CABLE
4 - POSITIVE JUMPER CABLE
5 - BATTERY POSITIVE CABLE
6 - BATTERY
7 - TEST INDICATOR
Fig. 9 Emergency Tow Hooks
1 - TOW HOOK
Fig. 10 Tow Vehicles With Approved Equipment
0 - 8 LUBRICATION & MAINTENANCEWJ
JUMP STARTING (Continued)

and therefore creates pressure in the pump. The tun-
ing of the front and rear axle orifices and valves
inside the gerotor pump is unique and each system
includes a torque-limiting pressure relief valve to
protect the clutch pack, which also facilitates vehicle
control under extreme side-to-side traction varia-
tions. The resulting pressure is applied to the clutch
pack and the transfer of torque is completed.
Under conditions in which opposite wheels are on
surfaces with widely different friction characteristics,
Vari-loktdelivers far more torque to the wheel on
the higher traction surface than do conventional
Trac-loktsystems. Because conventional Trac-lokt
differentials are initially pre-loaded to assure torque
transfer, normal driving (where inner and outer
wheel speeds differ during cornering, etc.) produces
torque transfer during even slight side-to-side speed
variations. Since these devices rely on friction from
this preload to transfer torque, normal use tends to
cause wear that reduces the ability of the differential
to transfer torque over time. By design, the Vari-lokt
system is less subject to wear, remaining more con-
sistent over time in its ability to transfer torque. The
coupling assembly is serviced as a unit. From a ser-
vice standpoint the coupling also benefits from using
the same lubricant supply as the ring and pinion
gears.
DIAGNOSIS AND TESTING
GEAR NOISE
Axle gear noise can be caused by insufficient lubri-
cant, incorrect backlash, tooth contact, worn/damaged
gears, or the carrier housing not having the proper
offset and squareness.
Gear noise usually happens at a specific speed
range. The noise can also occur during a specific type
of driving condition. These conditions are accelera-
tion, deceleration, coast, or constant load.
When road testing, first warm-up the axle fluid by
driving the vehicle at least 5 miles and then acceler-
ate the vehicle to the speed range where the noise is
the greatest. Shift out-of-gear and coast through the
peak-noise range. If the noise stops or changes
greatly:
²Check for insufficient lubricant.
²Incorrect ring gear backlash.
²Gear damage.
Differential side gears and pinions can be checked
by turning the vehicle. They usually do not cause
noise during straight-ahead driving when the gears
are unloaded. The side gears are loaded during vehi-
cle turns. A worn pinion mate shaft can also cause a
snapping or a knocking noise.
BEARING NOISE
The axle shaft, differential and pinion bearings can
all produce noise when worn or damaged. Bearing
noise can be either a whining, or a growling sound.
Pinion bearings have a constant-pitch noise. This
noise changes only with vehicle speed. Pinion bearing
noise will be higher pitched because it rotates at a
faster rate. Drive the vehicle and load the differen-
tial. If bearing noise occurs, the rear pinion bearing
is the source of the noise. If the bearing noise is
heard during a coast, the front pinion bearing is the
source.
Worn or damaged differential bearings usually pro-
duce a low pitch noise. Differential bearing noise is
similar to pinion bearing noise. The pitch of differen-
tial bearing noise is also constant and varies only
with vehicle speed.
Axle shaft bearings produce noise and vibration
when worn or damaged. The noise generally changes
when the bearings are loaded. Road test the vehicle.
Turn the vehicle sharply to the left and to the right.
This will load the bearings and change the noise
level. Where axle bearing damage is slight, the noise
is usually not noticeable at speeds above 30 mph.
LOW SPEED KNOCK
Low speed knock is generally caused by a worn
U-joint or by worn side±gear thrust washers. A worn
pinion shaft bore will also cause low speed knock.
VIBRATION
Vibration at the rear of the vehicle is usually
caused by a:
²Damaged drive shaft.
²Missing drive shaft balance weight(s).
²Worn or out-of-balance wheels.
²Loose wheel lug nuts.
²Worn U-joint(s).
²Loose/broken springs.
²Damaged axle shaft bearing(s).
²Loose pinion gear nut.
²Excessive pinion yoke run out.
²Bent axle shaft(s).
Check for loose or damaged front-end components
or engine/transmission mounts. These components
can contribute to what appears to be a rearend vibra-
tion. Do not overlook engine accessories, brackets
and drive belts.
All driveline components should be examined
before starting any repair.
(Refer to 22 - TIRES/WHEELS - DIAGNOSIS AND
TESTING)
3 - 92 REAR AXLE - 226RBAWJ
REAR AXLE - 226RBA (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
17. Viscous fan drive not operating
properly.17. Check fan drive operation and replace as
necessary. (Refer to 7 - COOLING/ENGINE/
FAN DRIVE VISCOUS CLUTCH -
DIAGNOSIS AND TESTING).
18. Cylinder head gasket leaking. 18. Check for cylinder head gasket leaks.
(Refer to 7 - COOLING - DIAGNOSIS AND
TESTING). For repair, (Refer to 9 -
ENGINE/CYLINDER HEAD - REMOVAL).
19. Heater core leaking. 19. Check heater core for leaks. (Refer to 24
- HEATING & AIR CONDITIONING/
PLUMBING/HEATER CORE - REMOVAL).
Repair as necessary.
20. Hydraulic fan speed too low or
inopertive.20. Check for
DTC code.
Check fan operation speeds.
Refer to fan speed operation table.
Low power steering pump output. Refer to
power steering pump diagnosis - 4.7L engine.
TEMPERATURE GAUGE
READING IS
INCONSISTENT
(FLUCTUATES, CYCLES
OR IS ERRATIC)1. During cold weather operation,
with the heater blower in the high
position, the gauge reading may
drop slightly.1. A normal condition. No correction is
necessary.
2. Temperature gauge or engine
mounted gauge sensor defective or
shorted. Also, corroded or loose
wiring in this circuit.2. Check operation of gauge and repair if
necessary. Refer to Group 8J, Instrument
cluster.
3. Gauge reading rises when vehicle
is brought to a stop after heavy use
(engine still running)3. A normal condition. No correction is
necessary. Gauge should return to normal
range after vehicle is driven.
4. Gauge reading high after
re-starting a warmed up (hot)
engine.4. A normal condition. No correction is
necessary. The gauge should return to
normal range after a few minutes of engine
operation.
5. Coolant level low in radiator (air
will build up in the cooling system
causing the thermostat to open late).5. Check and correct coolant leaks. (Refer to
7 - COOLING - DIAGNOSIS AND TESTING).
6. Cylinder head gasket leaking
allowing exhaust gas to enter
cooling system causing a thermostat
to open late.6. (a) Check for cylinder head gasket leaks.
(Refer to 7 - COOLING - DIAGNOSIS AND
TESTING).
(b) Check for coolant in the engine oil.
Inspect for white steam emitting from the
exhaust system. Repair as necessary.
WJCOOLING 7 - 7
COOLING (Continued)

ENGINE SYSTEMS
TABLE OF CONTENTS
page page
BATTERY SYSTEM......................... 1
CHARGING.............................. 24STARTING............................... 29
BATTERY SYSTEM
TABLE OF CONTENTS
page page
BATTERY SYSTEM
DESCRIPTION..........................2
OPERATION............................2
DIAGNOSIS AND TESTING - BATTERY
SYSTEM.............................2
CLEANING.............................5
INSPECTION...........................6
SPECIFICATIONS........................6
SPECIAL TOOLS........................7
BATTERY
DESCRIPTION..........................7
OPERATION............................8
DIAGNOSIS AND TESTING - BATTERY.......8
STANDARD PROCEDURE
STANDARD PROCEDURE - BATTERY
CHARGING...........................9
STANDARD PROCEDURE - USING MICRO
420 ELECTRICAL TESTER..............10
STANDARD PROCEDURE - BUILT-IN
INDICATOR TEST.....................11
STANDARD PROCEDURE - OPEN-CIRCUIT
VOLTAGE TEST.......................12
STANDARD PROCEDURE - IGNITION-OFF
DRAW TEST.........................13STANDARD PROCEDURE - CHECKING
BATTERY ELECTROLYTE LEVEL.........14
REMOVAL.............................15
INSTALLATION.........................15
BATTERY HOLDDOWN
DESCRIPTION.........................16
OPERATION...........................16
REMOVAL.............................16
INSTALLATION.........................16
BATTERY CABLE
DESCRIPTION.........................17
OPERATION...........................18
DIAGNOSIS AND TESTING - BATTERY
CABLES............................18
REMOVAL.............................19
INSTALLATION.........................20
BATTERY TRAY
DESCRIPTION.........................21
OPERATION...........................22
REMOVAL.............................22
INSTALLATION.........................23
WJENGINE SYSTEMS 8F - 1

BATTERY SYSTEM
DESCRIPTION
A single 12-volt battery system is standard factory-
installed equipment on this model. All of the compo-
nents of the battery system are located within the
engine compartment of the vehicle. The service infor-
mation for the battery system in this vehicle covers
the following related components, which are covered
in further detail elsewhere in this service manual:
²Battery- The storage battery provides a reli-
able means of storing a renewable source of electrical
energy within the vehicle.
²Battery Cables- The battery cables connect
the battery terminal posts to the vehicle electrical
system.
²Battery Holddown- The battery holddown
hardware secures the battery in the battery tray in
the engine compartment.
²Battery Tray- The battery tray provides a
secure mounting location in the vehicle for the bat-
tery and an anchor point for the battery holddown
hardware.
For battery system maintenance schedules and jump
starting procedures, see the owner's manual in the vehi-
cle glove box. Optionally, refer to Lubrication and Main-
tenance for the recommended battery maintenance
schedules and for the proper battery jump starting pro-
cedures. While battery charging can be considered a
maintenance procedure, the battery charging procedures
and related information are located in the standard pro-
cedures section of this service manual. This was done
because the battery must be fully-charged before any
battery system diagnosis or testing procedures can be
performed. Refer to Standard procedures for the proper
battery charging procedures.
OPERATION
The battery system is designed to provide a safe,
efficient, reliable and mobile means of delivering and
storing electrical energy. This electrical energy is
required to operate the engine starting system, as
well as to operate many of the other vehicle acces-
sory systems for limited durations while the engine
and/or the charging system are not operating. The
battery system is also designed to provide a reserve
of electrical energy to supplement the charging sys-
tem for short durations while the engine is running
and the electrical current demands of the vehicle
exceed the output of the charging system. In addition
to delivering, and storing electrical energy for the
vehicle, the battery system serves as a capacitor and
voltage stabilizer for the vehicle electrical system. It
absorbs most abnormal or transient voltages caused
by the switching of any of the electrical components
or circuits in the vehicle.
DIAGNOSIS AND TESTING - BATTERY SYSTEM
The battery, starting, and charging systems in the
vehicle operate with one another and must be tested
as a complete system. In order for the engine to start
and the battery to maintain its charge properly, all of
the components that are used in these systems must
perform within specifications. It is important that
the battery, starting, and charging systems be thor-
oughly tested and inspected any time a battery needs
to be charged or replaced. The cause of abnormal bat-
tery discharge, overcharging or early battery failure
must be diagnosed and corrected before a battery is
replaced and before a vehicle is returned to service.
The service information for these systems has been
separated within this service manual to make it eas-
ier to locate the specific information you are seeking.
However, when attempting to diagnose any of these
systems, it is important that you keep their interde-
pendency in mind.
The diagnostic procedures used for the battery,
starting, and charging systems include the most
basic conventional diagnostic methods, to the more
sophisticated On-Board Diagnostics (OBD) built into
the Powertrain Control Module (PCM). Use of an
induction-type milliampere ammeter, a volt/ohmme-
ter, a battery charger, a carbon pile rheostat (load
tester) and a 12-volt test lamp may be required. All
OBD-sensed systems are monitored by the PCM.
Each monitored circuit is assigned a Diagnostic Trou-
ble Code (DTC). The PCM will store a DTC in elec-
tronic memory for any failure it detects. Refer to
Charging System for the proper charging system on-
board diagnostic test procedures.
MICRO 420 ELECTRICAL SYSTEM TESTER
The Micro 420 automotive battery tester is
designed to help the dealership technicians diagnose
a defective battery. Follow the instruction manual
supplied with the tester to properly diagnose a vehi-
cle. If the instruction manual is not available refer to
the standard procedure in this section, which
includes the directions for using the Micro 420 elec-
trical system tester.
8F - 2 BATTERY SYSTEMWJ

BATTERY SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
THE BATTERY SEEMS
WEAK OR DEAD WHEN
ATTEMPTING TO START
THE ENGINE.1. The electrical system
ignition-off draw is excessive.1. Refer to the IGNITION-OFF DRAW TEST
Standard Procedure for the proper test
procedures. Repair the excessive ignition-off
draw, as required.
2. The charging system is
faulty.2. Determine if the charging system is performing
to specifications. Refer to Charging System for
additional charging system diagnosis and testing
procedures. Repair the faulty charging system, as
required.
3. The battery is discharged. 3. Determine the battery state-of-charge using the
Micro 420 battery tester. Refer to the Standard
Procedures in this section for additional test
procedures. Charge the faulty battery, as
required.
4. The battery terminal
connections are loose or
corroded.4. Refer to Battery Cables for the proper battery
cable diagnosis and testing procedures. Clean
and tighten the battery terminal connections, as
required.
5. The battery has an
incorrect size or rating for
this vehicle.5. Refer to Battery System Specifications for the
proper size and rating. Replace an incorrect
battery, as required.
6. The battery is faulty. 6. Determine the battery cranking capacity using
the Micro 420 battery tester. Refer to the
Standard Procedures in this section for additional
test procedures. Replace the faulty battery, as
required.
7. The starting system is
faulty.7. Determine if the starting system is performing
to specifications. Refer to Starting System for the
proper starting system diagnosis and testing
procedures. Repair the faulty starting system, as
required.
8. The battery is physically
damaged.8. Inspect the battery for loose terminal posts or a
cracked and leaking case. Replace the damaged
battery, as required.
WJBATTERY SYSTEM 8F - 3
BATTERY SYSTEM (Continued)