Dif JEEP GRAND CHEROKEE 2002 WJ / 2.G Manual PDF

ADJUSTMENTS
Ring and pinion gears are supplied as matched
sets only. The identifying numbers for the ring and
pinion gear are etched into the face of each gear (Fig.
6). A plus (+) number, minus (±) number or zero (0) is
etched into the face of the pinion gear. This number
is the amount (in thousandths of an inch) the depth
varies from the standard depth setting of a pinion
etched with a (0). The standard setting from the cen-
ter line of the ring gear to the back face of the pinion
is 109.52 mm (4.312 in.). The standard depth pro-
vides the best gear tooth contact pattern. Refer to
Backlash and Contact Pattern in this section for
additional information.
Compensation for pinion depth variance is
achieved with a select shim/oil baffle. The shims areplaced between the rear pinion bearing and the pin-
ion gear head (Fig. 7).
If a new gear set is being installed, note the depth
variance etched into both the original and replace-
ment pinion. Add or subtract this number from the
thickness of the original depth shim/oil slinger to
compensate for the difference in the depth variances.
Refer to the Pinion Gear Depth Variance chart.
Note where Old and New Pinion Marking columns
intersect. Intersecting figure represents plus or
minus the amount needed.
Note the etched number on the face of the pinion
gear head (±1, ±2, 0, +1, +2, etc.). The numbers rep-
resent thousands of an inch deviation from the stan-
dard. If the number is negative, add that value to the
required thickness of the depth shims. If the number
is positive, subtract that value from the thickness of
the depth shim. If the number is 0 no change is nec-
essary.
Fig. 6 PINION GEAR ID NUMBERS
1 - PRODUCTION NUMBERS
2 - DRIVE PINION GEAR DEPTH VARIANCE
3 - GEAR MATCHING NUMBER (SAME AS RING GEAR
NUMBER)
Fig. 7 ADJUSTMENT SHIM LOCATIONS
1 - PINION GEAR DEPTH SHIM
2 - DIFFERENTIAL BEARING SHIM
3 - RING GEAR
4 - DIFFERENTIAL BEARING SHIM
5 - COLLAPSIBLE SPACER
WJREAR AXLE - 226RBA 3 - 97
REAR AXLE - 226RBA (Continued)

PINION GEAR DEPTH VARIANCE
Original Pinion
Gear Depth
VarianceReplacement Pinion Gear Depth Variance
24232221 0 +1 +2 +3 +4
+4+0.008 +0.007 +0.006 +0.005 +0.004 +0.003 +0.002 +0.001 0
+3+0.007 +0.006 +0.005 +0.004 +0.003 +0.002 +0.001 020.001
+2+0.006 +0.005 +0.004 +0.003 +0.002 +0.001 020.00120.002
+1+0.005 +0.004 +0.003 +0.002 +0.001 020.00120.00220.003
0+0.004 +0.003 +0.002 +0.001 020.00120.00220.00320.004
21+0.003 +0.002 +0.001 020.00120.00220.00320.00420.005
22+0.002 +0.001 020.00120.00220.00320.00420.00520.006
23+0.001 020.00120.00220.00320.00420.00520.00620.007
24020.00120.00220.00320.00420.00520.00620.00720.008
PINION DEPTH MEASUREMENT
Measurements are taken with pinion bearing cups
and pinion bearings installed in the housing. Take
measurements with Pinion Gauge Set 6775 and Dial
Indicator C-3339 (Fig. 8).(1) Assemble Pinion Height Block 6739, Pinion
Block 8144 and rear pinion bearing onto Screw 6741
(Fig. 8).
(2) Insert assembled height gauge components,
rear bearing and screw into the housing through pin-
ion bearing cups (Fig. 9).
(3) Install front pinion bearing and Cone-nut 6740
hand tight (Fig. 8).
(4) Place Arbor Disc 6927A on Arbor D-115-3 in
position in the housing side bearing cradles (Fig. 10).
Install differential bearing caps in their original posi-
tions on arbor discs and tighten cap bolts to 85 N´m
(63 ft. lbs.).
Fig. 8 PINION GEAR DEPTH GAUGE
1 - DIAL INDICATOR
2 - ARBOR
3 - PINION HEIGHT BLOCK
4 - CONE
5 - SCREW
6 - PINION BLOCK
7 - SCOOTER BLOCK
8 - ARBOR DISC
Fig. 9 PINION HEIGHT BLOCK
1 - PINION BLOCK
2 - PINION HEIGHT BLOCK
3 - 98 REAR AXLE - 226RBAWJ
REAR AXLE - 226RBA (Continued)

NOTE: Arbor Discs 6927A has different step diame-
ters to fit other axles. Choose proper step for axle
being serviced.
(5) Assemble Dial Indicator C-3339 into Scooter
Block D-115-2 and secure set screw.
(6) Place Scooter Block/Dial Indicator in position
in axle housing so dial probe and scooter block are
flush against the rearward surface of the pinion
height block (Fig. 8). Hold scooter block in place and
zero the dial indicator face to the pointer. Tighten
dial indicator face lock screw.
(7) With scooter block still in position against the
pinion height block, slowly slide the dial indicator
probe over the edge of the pinion height block.
(8) Slide the dial indicator probe across the gap
between the pinion height block and the arbor bar
with the scooter block against the pinion height block
(Fig. 11). When the dial probe contacts the arbor bar,
the dial pointer will turn clockwise. Bring dial
pointer back to zero against the arbor bar, do not
turn dial face. Continue moving the dial probe to the
crest of the arbor bar and record the highest reading.
If the dial indicator can not achieve the zero reading,
the rear bearing cup or the pinion depth gauge set is
not installed correctly.
(9) Select a depth shim equal to the dial indicator
reading plus the pinion depth variance number
etched in the face of the pinion (Fig. 6). For example,
if the depth variance is ±2, add +0.002 in. to the dial
indicator reading.
DIFFERENTIAL BEARING PRELOAD & GEAR
BACKLASH
Differential side bearing preload and gear backlash
is achieved by selective shims positioned behind the
differential side bearing cones. The proper shim
thickness can be determined using slip-fit Dummy
Bearings 6929-A in place of the differential side bear-
ings and a Dial Indicator C-3339. Before proceeding
with the differential bearing preload and gear back-
lash measurements, measure the pinion gear depth
and prepare the pinion for installation. Establishing
proper pinion gear depth is essential to establishing
gear backlash and tooth contact patterns. After the
overall shim thickness to take up differential side
play is measured, the pinion is installed, and the
gear backlash shim thickness is measured. The over-
all shim thickness is the total of the dial indicator
reading and the preload specification added together.
The gear backlash measurement determines the
thickness of the shim used on the ring gear side of
the differential case. Subtract the gear backlash shim
thickness from the total overall shim thickness and
select that amount for the pinion gear side of the dif-
ferential (Fig. 12). Differential shim measurements
are performed with the spreader W-129-B removed.
SHIM SELECTION
NOTE: It is difficult to salvage the differential side
bearings during the removal procedure. Install
replacement bearings if necessary.
(1) Remove differential side bearings from differ-
ential case.
Fig. 10 GAUGE TOOLS IN HOUSING
1 - ARBOR DISC
2 - PINION BLOCK
3 - ARBOR
4 - PINION HEIGHT BLOCK
Fig. 11 PINION GEAR DEPTH MEASUREMENT
1 - ARBOR
2 - SCOOTER BLOCK
3 - DIAL INDICATOR
WJREAR AXLE - 226RBA 3 - 99
REAR AXLE - 226RBA (Continued)

(2) Install ring gear on differential case and
tighten bolts to specification.
(3)
Install Dummy Bearings 6929-A on differential case.
(4) Install differential case in the housing.
(5) Record the thickness of Dummy Shims 8107,
then insert the shims between the dummy bearings
and the differential housing (Fig. 13).(6) Install the bearing caps in their original posi-
tions and snug the bolts (Fig. 14).
(7) With a dead-blow hammer, seat the differential
dummy bearings to each side of the housing (Fig. 15)
and (Fig. 16).
Fig. 12 ADJUSTMENT SHIM LOCATIONS
1 - PINION GEAR DEPTH SHIM
2 - DIFFERENTIAL BEARING SHIM
3 - RING GEAR
4 - DIFFERENTIAL BEARING SHIM
5 - COLLAPSIBLE SPACER
Fig. 13 DUMMY SHIM POINT
1 - DUMMY SHIMS
2 - HOUSING
3 - DIFFERENTIAL CASE
4 - DUMMY BEARINGS
Fig. 14 TIGHTEN BEARING CAP BOLTS
1 - BEARING CAPS
2 - HOUSING
3 - DIFFERENTIAL CASE
Fig. 15 SEAT DUMMY BEARING
1 - HAMMER
2 - HOUSING
3 - DIFFERENTIAL CASE
3 - 100 REAR AXLE - 226RBAWJ
REAR AXLE - 226RBA (Continued)

(8) Thread Pilot Stud C-3288-B into rear cover bolt
hole below ring gear (Fig. 17).
(9) Attach the Dial Indicator C-3339 to pilot stud
and position the indicator plunger on the flat surface
between the ring gear bolts (Fig. 17).(10) Push and hold differential case to pinion gear
side of the housing and zero dial indicator (Fig. 18).
(11) Push and hold differential case to ring gear
side of the housing and record dial indicator reading
(Fig. 19).
(12) Add 0.0254 mm (0.001 in.) to the zero end
play total. This new total represents the thickness of
shims to compress, or preload the new bearings when
the differential is installed.
(13) Rotate dial indicator out of the way on the
pilot stud.
Fig. 16 SEAT DUMMY BEARING
1 - HOUSING
2 - HAMMER
3 - DIFFERENTIAL CASE
Fig. 17 DIFFERENTIAL SIDE PLAY MEASUREMENT
1 - DIFFERENTIAL CASE
2 - HOUSING
3 - PILOT STUD
4 - DIAL INDICATOR
Fig. 18 DIFFERENTIAL CASE PINION GEAR SIDE
1 - FORCE DIFFERENTIAL CASE TO PINION GEAR SIDE
2 - PILOT STUD
3 - DIAL INDICATOR
4 - DIAL INDICATOR FACE
Fig. 19 DIFFERENTIAL CASE RING GEAR SIDE
1 - READ DIAL INDICATOR
2 - FORCE DIFFERENTIAL CASE TO RING GEAR SIDE
3 - DIFFERENTIAL HOUSING
WJREAR AXLE - 226RBA 3 - 101
REAR AXLE - 226RBA (Continued)

(14) Remove differential case and dummy bearings
from the housing.
(15) Install the pinion gear in the housing. Install
the pinion yoke and establish the correct pinion
rotating torque.
(16) Install differential case and Dummy Bearings
6929-A in the housing.
(17) Install a single dummy shim in the ring gear
side. Install bearing caps and tighten bolts snug.
(18) Seat ring gear side dummy bearing (Fig. 16).
(19) Position the dial indicator plunger on a flat
surface between the ring gear bolt heads. (Fig. 17).
(20) Push and hold differential case toward pinion
gear and zero dial indicator (Fig. 20).
(21) Push and hold differential case to ring gear
side of the housing and record dial indicator reading
(Fig. 21). Add Dummy Shim thickness to this read-
ing. This will be the total shim thickness to achieve
zero backlash.
(22) Subtract 0.152 mm (0.006 in.) from the dial
indicator reading to compensate for backlash between
ring and pinion gears. This total is the thickness
shim required to achieve proper backlash.(23) Subtract backlash shim thickness from the
total preload shim thickness. The remainder is the
shim thickness required on the pinion side of the
housing.
(24) Rotate dial indicator out of the way on pilot
stud.
(25) Remove differential case and dummy bearings
from the housing.
(26) Install side bearings and cups on differential
case.
(27) Install spreader W-129-B, utilizing some items
from Adapter Set 6987, on the housing and spread
axle opening enough to receive differential case.
(28) Place the bearing preload shims in the hous-
ing against the axle tubes.
(29) Install differential case into the housing.
(30) Remove spreader from housing.
(31) Rotate the differential case several times to
seat the side bearings.
Fig. 20 ZERO DIAL INDICATOR
1 - DIAL INDICATOR FACE
2 - FORCE DIFFERENTIAL CASE TO PINION GEAR SIDE
3 - PINION GEAR
4 - HOUSING
5 - DIFFERENTIAL CASE
Fig. 21 DIFFERENTIAL CASE RING GEAR SIDE
1 - READ DIAL INDICATOR
2 - FORCE DIFFERENTIAL CASE TO RING GEAR SIDE
3 - PINION GEAR
4 - DIFFERENTIAL HOUSING
5 - DIFFERENTIAL CASE
3 - 102 REAR AXLE - 226RBAWJ
REAR AXLE - 226RBA (Continued)

(32) Position the indicator plunger against a ring
gear tooth (Fig. 22).
(33) Push and hold ring gear upward while not
allowing the pinion gear to rotate.
(34) Zero dial indicator face to pointer.
(35) Push and hold ring gear downward while not
allowing the pinion gear to rotate. Dial indicator
reading should be between 0.076 mm (0.003 in.) and
0.15 mm (0.006 in.). If backlash is not within specifi-
cations transfer the necessary amount of shim thick-
ness from one side of the housing to the other (Fig.
23).
(36) Verify differential case and ring gear runout
by measuring ring to pinion gear backlash at eight
locations around the ring gear. Readings should not
vary more than 0.05 mm (0.002 in.). If readings vary
more than specified, the ring gear or the differential
case is defective.
After the proper backlash is achieved, perform
Gear Contact Pattern procedure.
GEAR CONTACT PATTERN
The ring gear and pinion teeth contact patterns
will show if the pinion depth is correct in the axle
housing. It will also show if the ring gear backlashhas been adjusted correctly. The backlash can be
adjusted within specifications to achieve desired
tooth contact patterns.
(1) Apply a thin coat of hydrated ferric oxide or
equivalent to the drive and coast side of the ring gear
teeth.
(2) Wrap, twist and hold a shop towel around the
pinion yoke to increase the turning resistance of the
pinion. This will provide a more distinct contact pat-
tern.
(3) With a boxed end wrench on a ring gear bolt,
rotate the differential case one complete revolution in
both directions while a load is being applied from
shop towel.
The areas on the ring gear teeth with the greatest
degree of contact against the pinion teeth will squee-
gee the compound to the areas with the least amount
of contact. Note and compare patterns on the ring
gear teeth to Gear Tooth Contact Patterns chart (Fig.
24) and adjust pinion depth and gear backlash as
necessary.
Fig. 22 RING GEAR BACKLASH
1 - DIAL INDICATOR
Fig. 23 BACKLASH SHIM
WJREAR AXLE - 226RBA 3 - 103
REAR AXLE - 226RBA (Continued)

DIFFERENTIAL BEARING PRELOAD CHECK
The final check on the differential assembly before
installing the axles is torque to rotate pinion and dif-
ferential combined. This will verify the correct differ-
ential bearing preload.Torque to rotate the differential and pinion should
be the torque to rotate the pinion plus 0.79-1.24 N´m
(7-11 in. lbs.).
SPECIFICATIONS
AXLE SPECIFICATIONS
DESCRIPTION SPECIFICATION
Axle Ratio 3.31, 3.55, 3.73, 3.91
Differential Bearing Preload 0.025 mm (0.001 in.)
Ring Gear Diameter 226 mm (8.9 in.)
Ring Gear Backlash 0.076.-0.15 mm (0.003-0.006 in.)
Pinion Gear Std. Depth 109.52 mm (4.312 in.)
Pinion Bearing Preload - Original Bearings 1-2 N´m (10-20 in. lbs.)
Pinion Bearing Preload - New Bearings 2.8-4 N´m (25-35 in. lbs.)
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Differential Cover Bolts 41 30 -
Bearing Cap Bolts 85 63 -
Ring Gear Bolts 136 100 -
Pinion Nut 298-380 220-280 -
Pinion Mate Shaft Screw 17.6 13 -
Axle Bearing Retainer Plate
Nuts61 45 -
WJREAR AXLE - 226RBA 3 - 105
REAR AXLE - 226RBA (Continued)

AXLE SHAFTS
REMOVAL
(1) Place transmission in neutral.
(2) Raise and support vehicle.
(3) Remove wheel and tire assembly.
(4) Remove brake caliper and rotor.
(5) Remove nuts holding axle retainer plate to axle
tube from the rear of the axle flange.
(6) Pull axle shaft from the axle with Slide Ham-
mer 7420 and Adapter 6790. Mount the adapter to
the axle with lug nuts.
NOTE: The axle bearing race is normally loose in
the axle tube.
INSTALLATION
(1) Insall axle into the axle tube with the flat area
of the retainer plate upward.
(2) Insert retaining plate studs into the brake
backing plate and axle tube flange.
(3) Install retainer nuts and tighten nuts to 61
N´m (45 ft. lbs.).
(4) Install the brake rotor and caliper.
(5) Install wheel and tire.
(6) Check and fill the differential with gear lubri-
cant.
(7) Lower vehicle.
AXLE BEARINGS/SEALS
REMOVAL
(1) Remove axle shaft from vehicle.
NOTE: The axle bearing race is normally loose in
the axle tube.
(2) Drill a shallow hole into soft steel axle bearing
retaining ring with a 3/8 in. drill bit (Fig. 25). Use a
drill depth stop to avoid marking the axle.
(3) With a cold chisel cut the retaining ring across
drilled hole. (Fig. 26)
(4) Slide retaining ring from axle shaft.
Fig. 25 DRILL RETAINING RING
1 - DRILL BIT
2 - AXLE
3 - RETAINING PLATE
4 - RETAINING RING
Fig. 26 RETAINING RING
1 - AXLE
2 - COLD CHISEL
3 - VISE
4 - RETAINING RING
WJREAR AXLE - 226RBA 3 - 109

(10) Remove pinion seal with Remover 7794-A and
a slide hammer (Fig. 33).
INSTALLATION
(1) Apply a light coating of gear lubricant on the
lip of pinion seal. Install seal with an appropriate in
installer (Fig. 34).
(2) Install yoke on the pinion gear with Installer
C-3718 and Spanner Wrench 6958 (Fig. 35).
(3) Install anewnut on the pinion gear.Tighten
the nut only enough to remove the shaft end
play.
CAUTION: Do not exceed the minimum tightening
torque 298 N´m (220 ft. lbs.) when installing the pin-
ion yoke retaining nut at this point. Damage to col-
lapsible spacer or bearings may result.(4) Rotate the pinion a minimum of ten times and
verify pinion rotates smoothly. Rotate the pinion
shaft using an inch pound torque wrench. Rotating
torque should be equal to the reading recorded dur-
ing removal, plus 0.56 N´m (5 in. lbs.) (Fig. 36).
Fig. 33 Pinion Seal Remover
1 - REMOVER
2 - SLIDE HAMMER
3 - PINION SEAL
Fig. 34 PINION SEAL INSTALLER
1 - HANDLE
2 - INSTALLER
Fig. 35 PINION YOKE INSTALLER
1 - INSTALLER
2 - PINION YOKE
3 - DIFFERENTIAL HOUSING
4 - SPANNER WRENCH
Fig. 36 PINION ROTATING TORQUE
1 - TORQUE WRENCH
2 - PINION YOKE
3 - 112 REAR AXLE - 226RBAWJ
PINION SEAL (Continued)