Engine JEEP GRAND CHEROKEE 2003 WJ / 2.G User Guide

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)

STANDARD PROCEDURE - CASTER
Before each alignment reading the vehicle should
be jounced (rear first, then front). Grasp each
bumper at the center and jounce the vehicle up and
down three times. Always release the bumper in the
down position.
To obtain an accurate alignment, a 4 wheel align-
ment machine must be used and the equipment cali-
bration verified.
The wheel caster angle is preset. This angle is not
adjustable and cannot be altered.
STANDARD PROCEDURE - TOE POSITION
Before each alignment reading the vehicle should
be jounced (rear first, then front). Grasp each
bumper at the center and jounce the vehicle up and
down three times. Always release the bumper in the
down position.To obtain an accurate alignment, a 4 wheel align-
ment machine must be used and the equipment cali-
bration verified.
NOTE: For an accurate wheel toe position adjust-
ment the engine must be engine running.
(1) Apply parking brakes.
(2) Start the engine and turn wheels both ways
before straightening the steering wheel. Center and
secure the steering wheel.
(3) Loosen the tie rod adjustment sleeve clamp
bolts (Fig. 2).
(4) Turn the sleeve to obtain the preferred positive
TOE-IN specification. Position the clamp bolts as
shown (Fig. 2) for proper clearance.
(5) Tighten the clamp bolts to 68 N´m (50 ft. lbs.).
Fig. 1 Wheel Alignment Measurements
1 - WHEEL CENTERLINE
2 - NEGATIVE CAMBER ANGLE
3 - PIVOT CENTERLINE
4 - SCRUB RADIUS
5 - TRUE VERTICAL6 - KING PIN
7 - VERTICAL
8 - POSITIVE CASTER
2 - 4 WHEEL ALIGNMENTWJ
WHEEL ALIGNMENT (Continued)

NOTE: Make sure the toe setting does not change
during clamp tightening.
(6) Verify alignment specifications, then turn the
engine off.
STEERING WHEEL CENTERING
NOTE: The steering wheel can be centered without
affecting the toe position.
(1) Loosen the drag link adjustment sleeve clamp
bolts.
(2) Turn the adjustment sleeve to center the
wheel.
(3) Position the clamp bolts as shown (Fig. 2)for
proper clearance.
(4) Tighten the clamp bolts to 68 N´m (50 ft. lbs.).
(5) Road test the vehicle to verify the wheel is cen-
tered.
SPECIFICATIONS
ALIGNMENT
NOTE: Specifications are in degrees.
FRONT WHEELS - STANDARD SUSPENSION
SPECIFICATIONS
DESCRIPTION SPECIFICATION
PREFERRED CASTER
+ 6.75ÉCAMBER
20.37ÉTOTAL
TOE-IN
+ 0.20É
RANGE + 6.0É to
+ 7.5É20.75É
to + 0.5É+ .14É to
+ .26É
MAX RT/LT
DIFFERENCE0.5É 0.5É 0.5É
FRONT WHEELS - UP-COUNTRY SUSPENSION
SPECIFICATIONS
DESCRIPTION SPECIFICATION
PREFERRED CASTER
+ 6.5ÉCAMBER
20.37ÉTOTAL
TOE-IN
+ 0.20É
RANGE + 5.7É to
+ 7.2É20.75É
to+0É+ 0.0É to
+ .36É
MAX RT/LT
DIFFERENCE0.5É 0.5É 0.06É
REAR AXLE
SPECIFICATIONS
DESCRIPTION SPECIFICATION
PREFERRED CAMBER
±.37ÉTHRUST
ANGLE
0ÉTOTAL
TOE-IN
+.37É
RANGE 0É to
±.75É  0.25É 0É to
+.70É
Fig. 2 Steering Linkage
1 - DRAG LINK ADJUSTMENT SLEEVE
2 - TIE ROD ADJUSTMENT SLEEVE
WJWHEEL ALIGNMENT 2 - 5
WHEEL ALIGNMENT (Continued)

SHOCK
DESCRIPTION
The top of the shock absorbers are bolted to the
body. The bottom of the shocks are bolted to the axle
brackets. The standard shocks have conventional
twin tube construction and are low pressure gas
charged. Gas charging prevents cavitation during
rough road operation. Up-Country shocks are mono
tube design and are high pressure gas charged.
OPERATION
The shock absorbers dampen jounce and rebound
motion of the vehicle over various road conditions
and limit suspension rebound travel.
REMOVAL
(1) Remove the nut, retainer and grommet from
the shock stud in the engine compartment (Fig. 8).
(2) Raise and support the front axle.
(3) Remove the lower mounting nuts from the axle
bracket (Fig. 9). Remove the shock absorber.
INSTALLATION
(1) Position the lower retainer and grommet on the
shock stud. Insert the shock absorber through the
shock tower hole.
(2) Install the lower shock studs into the axle
bracket.
(3) Install the mounting nuts and tighten to 28
N´m (250 in. lbs.).
(4) Remove support and lower the vehicle.(5) Install the upper grommet, retainer and nut on
the stud in the engine compartment. Hold the shock
stud witha8mmwrench and tighten the nut to 35
N´m (26 ft. lbs.).SPRING
DESCRIPTION
The coil springs mount up in the wheelhouse which
is part of the unitized body bracket. A rubber dough-
nut isolator is located between the top of the spring
and the body. The bottom of the spring seats on a
axle isolator made of rubber with a steel insert.
Fig. 7 Lower Suspension Arm
1 - LOWER SUSPENSION ARM
2 - FRAME RAIL BRACKET
3 - AXLE BRACKET
Fig. 8 Upper Shock Mounting
1 - RETAINER
2 - STUD
3 - NUT
4 - GROMMET
Fig. 9 Lower Shock Mounting
1 - SHOCK ABSORBER
2 - MOUNTING NUTS
2 - 12 FRONTWJ
LOWER CONTROL ARM (Continued)

DIFFERENTIAL & DRIVELINE
TABLE OF CONTENTS
page page
PROPELLER SHAFT......................1
FRONT TUBE AXLE......................14
FRONT AXLE - 186FBI....................15REAR AXLE - 198RBI.....................50
REAR AXLE - 226RBA....................90
PROPELLER SHAFT
TABLE OF CONTENTS
page page
PROPELLER SHAFT
DIAGNOSIS AND TESTING................1
STANDARD PROCEDURES................3
SPECIFICATIONS........................5
SPECIAL TOOLS........................5
PROPELLER SHAFT - FRONT
REMOVAL.............................6
INSTALLATION..........................6
PROPELLER SHAFT - FRONT 4.7L
REMOVAL.............................6INSTALLATION..........................7
PROPELLER SHAFT - REAR
REMOVAL.............................7
INSTALLATION..........................7
SINGLE CARDAN UNIVERSAL JOINTS
DISASSEMBLY..........................8
ASSEMBLY.............................9
DOUBLE CARDAN UNIVERSAL JOINTS
DISASSEMBLY..........................9
ASSEMBLY............................10
PROPELLER SHAFT
DIAGNOSIS AND TESTING
VIBRATION
Tires that are out-of-round, or wheels that are
unbalanced, will cause a low frequency vibration.
(Refer to 22 - TIRES/WHEELS - DIAGNOSIS AND
TESTING)
Brake rotors that are unbalanced will cause a
harsh, low frequency vibration. (Refer to 5 - BRAKES
- DIAGNOSIS AND TESTING)Driveline vibration can also result from loose or
damaged engine mounts.
Propeller shaft vibration increases as the vehicle
speed is increased. A vibration that occurs within a
specific speed range is not usually caused by a pro-
peller shaft being unbalanced. Defective universal
joints, or an incorrect propeller shaft angle, are usu-
ally the cause of such a vibration.
WJDIFFERENTIAL & DRIVELINE 3 - 1

DRIVELINE VIBRATION
Drive Condition Possible Cause Correction
Propeller Shaft Noise 1) Undercoating or other foreign material
on shaft.1) Clean exterior of shaft and wash with
solvent.
2) Loose U-joint clamp screws. 2) Install new clamps and screws and
tighten to proper torque.
3) Loose or bent U-joint yoke or
excessive runout.3) Install new yoke.
4) Incorrect driveline angularity. 4) Measure and correct driveline angles.
5) Rear spring center bolt not in seat. 5) Loosen spring u-bolts and seat center
bolt.
6) Worn U-joint bearings. 6) Install new U-joint.
7) Propeller shaft damaged or out of
balance.7) Installl new propeller shaft.
8) Broken rear spring. 8) Install new rear spring.
9) Excessive runout or unbalanced
condition.9) Re-index propeller shaft, test, and
evaluate.
10) Excessive drive pinion gear shaft
runout.10) Re-index propeller shaft and evaluate.
11) Excessive axle yoke deflection. 11) Inspect and replace yoke if necessary.
12) Excessive transfer case runout. 12) Inspect and repair as necessary.
Universal Joint Noise 1) Loose U-joint clamp screws. 1) Install new clamps and screws and
tighten to proper torque.
2) Lack of lubrication. 2) Replace U-joints as necessary.
BALANCE
NOTE: Removing and re-indexing the propeller
shaft 180É relative to the yoke may eliminate some
vibrations.
If propeller shaft is suspected of being unbalanced,
it can be verified with the following procedure:
(1) Raise the vehicle.
(2) Clean all the foreign material from the propel-
ler shaft and the universal joints.
(3) Inspect the propeller shaft for missing balance
weights, broken welds, and bent areas.If the pro-
peller shaft is bent, it must be replaced.
(4) Inspect the universal joints to ensure that they
are not worn, are properly installed, and are cor-
rectly aligned with the shaft.
(5) Check the universal joint clamp screws torque.
(6) Remove the wheels and tires. Install the wheel
lug nuts to retain the brake drums or rotors.
(7) Mark and number the shaft six inches from the
yoke end at four positions 90É apart.
(8) Run and accelerate the vehicle until vibration
occurs. Note the intensity and speed the vibration
occurred. Stop the engine.(9) Install a screw clamp at position 1 (Fig. 1).
Fig. 1 CLAMP SCREW - POSITION 1
1 - CLAMP
2 - SCREWDRIVER
3 - 2 PROPELLER SHAFTWJ
PROPELLER SHAFT (Continued)

(10) Start the engine and re-check for vibration. If
there is little or no change in vibration, move the
clamp to one of the other three positions. Repeat the
vibration test.
(11) If there is no difference in vibration at the
other positions, the source of the vibration may not
be propeller shaft.
(12) If the vibration decreased, install a second
clamp (Fig. 2) and repeat the test.
(13) If the additional clamp causes an additional
vibration, separate the clamps (1/4 inch above and
below the mark). Repeat the vibration test (Fig. 3).
(14) Increase distance between the clamp screws
and repeat the test until the amount of vibration is
at the lowest level. Bend the slack end of the clamps
so the screws will not loosen.
(15) If the vibration remains unacceptable, apply
the same steps to the front end of the propeller shaft.
(16) Install the wheel and tires. Lower the vehicle.RUNOUT
(1) Remove dirt, rust, paint, and undercoating
from the propeller shaft surface where the dial indi-
cator will contact the shaft.
(2) The dial indicator must be installed perpendic-
ular to the shaft surface.
(3) Measure runout at the center and ends of the
shaft sufficiently far away from weld areas to ensure
that the effects of the weld process will not enter into
the measurements.
(4) Refer to Runout Specifications chart.
(5) If the propeller shaft runout is out of specifica-
tion, remove the propeller shaft, index the shaft 180É,
and re-install the propeller shaft. Measure shaft
runout again.
(6) If the propeller shaft runout is now within
specifications, mark the shaft and yokes for proper
orientation.
(7) If the propeller shaft runout is not within spec-
ifications, verify that the runout of the transmission/
transfer case and axle are within specifications.
Correct as necessary and re-measure propeller shaft
runout.
(8) Replace the propeller shaft if the runout still
exceeds the limits.
RUNOUT SPECIFICATIONS
Front of Shaft 0.020 in. (0.50 mm)
Center of Shaft 0.025 in. (0.63 mm)
Rear of Shaft 0.020 in. (0.50 mm)
note:
Measure front/rear runout approximately 3 inches (76
mm) from the weld seam at each end of the shaft
tube for tube lengths over 30 inches. For tube lengths
under 30 inches, the maximum allowed runout is
0.020 in. (0.50 mm) for the full length of the tube.
STANDARD PROCEDURES
This procedure applies to both the front propeller
shafts and the rear propeller shaft. To obtain the
front (output) angle on the C/V front propeller shaft,
the inclinometer is placed on the machined ring of
the pinion flange. To obtain the propeller shaft angle
measurement on the C/V front propeller shaft, the
inclinometer is placed on the propeller shaft tube.
PROPELLER SHAFT ANGLE
(1) Raise and support the vehicle at the axles as
level as possible. Allow the wheels and propeller
shaft to turn.
(2) Remove any external bearing snap rings from
universal joint if equipped, so the inclinometer base
will sits flat.
Fig. 2 TWO CLAMP SCREWS
Fig. 3 CLAMP SCREWS SEPARATED
1 - ó INCH
WJPROPELLER SHAFT 3 - 3
PROPELLER SHAFT (Continued)

FRONT AXLE - 186FBI
TABLE OF CONTENTS
page page
FRONT AXLE - 186FBI
DESCRIPTION.........................15
OPERATION...........................15
DIAGNOSIS AND TESTING................16
REMOVAL.............................20
INSTALLATION.........................21
ADJUSTMENTS........................21
SPECIFICATIONS.......................30
SPECIAL TOOLS.......................31
AXLE SHAFTS
REMOVAL.............................34
INSTALLATION.........................34
AXLE SHAFT SEALS
REMOVAL.............................35
INSTALLATION.........................35
AXLE - C/V JOINT
REMOVAL.............................35
INSTALLATION.........................35
AXLE - U-JOINT
REMOVAL.............................36INSTALLATION.........................37
PINION SEAL
REMOVAL.............................37
INSTALLATION.........................37
COLLAPSIBLE SPACER
REMOVAL.............................39
INSTALLATION.........................39
DIFFERENTIAL
REMOVAL.............................40
DISASSEMBLY.........................42
ASSEMBLY............................42
INSTALLATION.........................43
DIFFERENTIAL CASE BEARINGS
REMOVAL.............................44
INSTALLATION.........................44
PINION GEAR/RING GEAR
REMOVAL.............................45
INSTALLATION.........................46
FRONT AXLE - 186FBI
DESCRIPTION
The Front Beam-design Iron (FBI) axle consists of
a cast iron differential housing with axle shaft tubes
extending from either side. The tubes are pressed
into the differential housing and welded. The axles
are semi-floating axle shafts, meaning the loads are
supported by the hub bearings. The axle shafts are
retained by nuts at the hub bearings.
The differential case is a one-piece design. Differ-
ential bearing preload and ring gear backlash is
adjusted by the use of shims located between the dif-
ferential bearing cups and housing. Pinion bearing
preload is set and maintained by the use of a collaps-
ible spacer. A differential cover provides a means for
inspection and servicing.
An optional Vari-Loktdifferential has a one-piece
differential case which contains the gerotor pump
assembly and the clutch mechinism. This unit is ser-
viced as an assembly.
OPERATION
The axle receives power from the transfer case
through the front propeller shaft. The front propeller
shaft is connected to the pinion gear which rotatesthe differential through the gear mesh with the ring
gear bolted to the differential case. The engine power
is transmitted to the axle shafts through the pinion
mate and side gears. The side gears are splined to
the axle shafts.
STANDARD DIFFERENTIAL
During straight-ahead driving, the differential pinion
gears do not rotate on the pinion mate shaft. This
occurs because input torque applied to the gears is
divided and distributed equally between the two side
gears. As a result, the pinion gears revolve with the pin-
ion mate shaft but do not rotate around it (Fig. 1).
When turning corners, the outside wheel must
travel a greater distance than the inside wheel to
complete a turn. The difference must be compensated
for to prevent the tires from scuffing and skidding
through turns. To accomplish this, the differential
allows the axle shafts to turn at unequal speeds (Fig.
2). In this instance, the input torque applied to the
pinion gears is not divided equally. The pinion gears
now rotate around the pinion mate shaft in opposite
directions. This allows the side gear and axle shaft
attached to the outside wheel to rotate at a faster
speed.
WJFRONT AXLE - 186FBI 3 - 15

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 rear-end
vibration. Do not overlook engine accessories, brack-
ets and drive belts.
All driveline components should be examined
before starting any repair.
(Refer to 22 - TIRES/WHEELS - DIAGNOSIS AND
TESTING)
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted
into gear (or the clutch engaged), can be caused by:
²High engine idle speed.
²Transmission shift operation.
²Loose engine/transmission/transfer case mounts.
²Worn U-joints.
²Loose spring mounts.
²Loose pinion gear nut and yoke.
²Excessive ring gear backlash.
²Excessive side gear to case clearance.
The source of a snap or a clunk noise can be deter-
mined with the assistance of a helper. Raise the vehi-
cle on a hoist with the wheels free to rotate. Instruct
the helper to shift the transmission into gear. Listen
for the noise, a mechanics stethoscope is helpful in
isolating the source of a noise.
WJFRONT AXLE - 186FBI 3 - 17
FRONT AXLE - 186FBI (Continued)