Condition Possible Causes Correction
Gear Teeth Broke 1. Overloading. 1. Replace gears. Examine other
gears and bearings for possible
damage.
2. Erratic clutch operation. 2. Replace gears and examine the
remaining parts for damage. Avoid
erratic clutch operation.
3. Ice-spotted pavement. 3. Replace gears and examine
remaining parts for damage.
4. Improper adjustments. 4. Replace gears and examine
remaining parts for damage. Ensure
ring gear backlash is correct.
Axle Noise 1. Insufficient lubricant. 1. Fill differential with the correct
fluid type and quantity.
2. Improper ring gear and pinion
adjustment.2. Check ring gear and pinion
contact pattern.
3. Unmatched ring gear and pinion. 3. Replace gears with a matched
ring gear and pinion.
4. Worn teeth on ring gear and/or
pinion.4. Replace ring gear and pinion.
5. Loose pinion bearings. 5. Adjust pinion bearing pre-load.
6. Loose differential bearings. 6. Adjust differential bearing
pre-load.
7. Mis-aligned or sprung ring gear. 7. Measure ring gear run-out.
Replace components as necessary.
8. Loose differential bearing cap
bolts.8. Inspect differential components
and replace as necessary. Ensure
that the bearing caps are torqued
tot he proper specification.
9. Housing not machined properly. 9. Replace housing.
KJFRONT AXLE - 186FIA 3 - 23
FRONT AXLE - 186FIA (Continued)
(8) Install lower control arms, refer to 2 Suspen-
sion for procedures.
(9) Install new half shaft hub nuts and tighten to
136 N´m (100 ft. lbs.).
(10) Install axle vent hose.
(11) Fill differential with gear lubricant.
(12) Install skid plate.
(13) Install wheel and tire assemblies.
(14) Remove support and lower vehicle.
(15) Check vehicle alignment.
ADJUSTMENTS
Ring and pinion gears are supplied as matched
sets only. The identifying numbers for the ring and
pinion gear are etched onto each gear (Fig. 8). 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 center line
of the ring gear to the back face of the pinion is 92.1
mm (3.625 in.). The standard depth provides the best
gear tooth contact pattern. Refer to Backlash and
Contact Pattern Analysis paragraph in this section
for additional information.
Fig. 6 RIGHT AXLE BRACKET
1 - RIGHT AXLE BRACKET
2 - FRONT BRACKET BOLT
3 - REAR BRACKET BOLT
Fig. 7 LEFT REAR AXLE BRACKET
1 - LEFT REAR AXLE BRACKET
2 - BRACKET BOLT
Fig. 8 PINION GEAR ID NUMBERS
1 - PRODUCTION NUMBERS
2 - DRIVE PINION GEAR DEPTH VARIANCE
3 - GEAR MATCHING NUMBER
KJFRONT AXLE - 186FIA 3 - 25
FRONT AXLE - 186FIA (Continued)
PINION DEPTH MEASUREMENT
Measurements are taken with pinion bearing cups
and pinion bearings installed in the housing. Take
measurements with Pinion Gauge Set and Dial Indi-
cator C-3339 (Fig. 10).
(1) Assemble Pinion Height Block 6739, Pinion
Block 8804 and rear pinion bearing onto Screw 6741
(Fig. 10).
(2) Insert height gauge components into the hous-
ing through pinion bearing cups.
(3) Install front pinion bearing and hand tight
Cone-nut 6740 onto the screw.
(4) Position Arbor Disc 6732 and Arbor D-115-3
into the housing bearing cradles. Install differential
bearing caps on Arbor Discs and tighten bolts to 41
N´m (30 ft. lbs.) (Fig. 11).
NOTE: Arbor Discs 6732 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) Position Scooter Block/Dial Indicator flush on
the pinion height block. Hold the scooter block and
zero the dial indicator.
(7) Slowly slide the scooter block across the pinion
height block over to the arbor (Fig. 12). Move the
scooter block till the dial indicator probe crests the
arbor and record the highest reading.
(8) Select a shim/oil slinger equal to the dial indi-
cator reading plus the pinion depth variance number
etched in the face of the pinion (Fig. 8). For example,
if the depth variance is ±2, add +0.002 in. to the dial
indicator reading.
DIFFERENTIAL
Differential bearing preload and gear backlash is
adjusted by the use of selective shims. The shims are
located between the differential bearing cups and the
differential housing. The proper shim thickness can
be determined using slip-fit Dummy Bearings D-348
in place of the differential side bearings and a Dial
Indicator C-3339. Before proceeding with the differ-
ential bearing preload and gear backlash measure-
ments, 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 mea-
sured, the pinion is installed, and the gear backlash
Fig. 10 PINION GEAR DEPTH TOOLS
1 - DIAL INDICATOR
2 - ARBOR
3 - PINION HEIGHT BLOCK
4 - CONE
5 - SCREW
6 - PINION BLOCK
7 - SCOOTER BLOCK
8 - ARBOR DISC
Fig. 11 DEPTH TOOLS IN HOUSING
1 - PINION HEIGHT BLOCK
2 - ARBOR DISC
3 - ARBOR
4 - PINION BLOCK
KJFRONT AXLE - 186FIA 3 - 27
FRONT AXLE - 186FIA (Continued)
(28) Place the bearing preload shims in the axle
housing, against the axle tubes.
(29) Install differential case into the housing.
(30) Remove spreader from the housing.
(31) Rotate the differential case several times to
seat the side bearings.
(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 0.12 mm (0.005 in.) and
0.20 mm (0.008 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 Analysis procedure.
GEAR CONTACT PATTERN
The ring gear and pinion teeth contact patterns
will show if the pinion depth is correct in the hous-
ing. It will also show if the ring gear backlash has
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 nec-
essary.Fig. 22 RING GEAR BACKLASH
1 - DIAL INDICATOR
2 - RING GEAR
Fig. 23 BACKLASH SHIMS
KJFRONT AXLE - 186FIA 3 - 31
FRONT AXLE - 186FIA (Continued)
(4) Remove the dial indicator.
(5) Install differential case in the housing. Ensure
differential bearing cups remain on the bearings and
preload shims are seated in the housing. Tap differ-
ential case to ensure bearings cups are seated in the
housing.
(6) Install bearing caps to their original locations
and loosely install cap bolts.
(7) Remove differential housing spreader (Fig. 43).
(8) Tighten the bearing cap bolts in a criss-cross
pattern to 54-68 N´m (39-50 ft. lbs.).
(9) Install the right axle shaft.
(10) Apply a 6.38mm (1/4 in.) bead of red Mopar
Silicone Sealer or equivalent to the housing cover.
CAUTION: If cover is not installed within 3 to 5 min-
utes, the cover must be cleaned and new RTV
applied or adhesion quality will be compromised.
(11) Install differential housing cover and tighten
bolts in a criss-cross pattern to 19-26 N´m (14-19 ft.
lbs.).(12) Install axle assembly in vehicle.
(13) Fill differential with lubricant and install fill
plug.
DIFFERENTIAL CASE
BEARINGS
REMOVAL
(1) Remove differential from the housing.
(2) Remove bearings from the differential case
with Puller/Press C-293-PA, Adapters C-293-39 and
Plug SP-3289 (Fig. 44).
Fig. 43 DIFFERENTIAL SPREADER
1 - DIFFERENTIAL HOUSING
2 - SAFETY CLAMPS
3 - SPREADER
4 - TURNBUCKLE
Fig. 44 DIFFERENTIAL BEARING PULLER
1 - PULLER
2 - ADAPTERS
3 - BEARING
4 - DIFFERENTIAL
5 - PLUG
KJFRONT AXLE - 186FIA 3 - 43
DIFFERENTIAL (Continued)
Condition Possible Causes Correction
Loss Of Lubricant 1. Lubricant level too high. 1. Drain lubricant to the correct
level.
2. Worn axle shaft seals. 2. Replace seals.
3. Cracked differential housing. 3. Repair as necessary.
4. Worn pinion seal. 4. Replace seal.
5. Worn/scored yoke. 5. Replace yoke and seal.
6. Axle cover not properly sealed. 6. Remove, clean, and re-seal
cover.
Axle Overheating 1. Lubricant level low. 1. Fill differential to correct level.
2. Improper grade of lubricant. 2. Fill differential with the correct
fluid type and quantity.
3. Bearing pre-loads too high. 3. Re-adjust bearing pre-loads.
4. Insufficient ring gear backlash. 4. Re-adjust ring gear backlash.
Gear Teeth Broke 1. Overloading. 1. Replace gears. Examine other
gears and bearings for possible
damage.
2. Erratic clutch operation. 2. Replace gears and examine the
remaining parts for damage. Avoid
erratic clutch operation.
3. Ice-spotted pavement. 3. Replace gears and examine
remaining parts for damage.
4. Improper adjustments. 4. Replace gears and examine
remaining parts for damage. Ensure
ring gear backlash is correct.
Axle Noise 1. Insufficient lubricant. 1. Fill differential with the correct
fluid type and quantity.
2. Improper ring gear and pinion
adjustment.2. Check ring gear and pinion
contact pattern. Adjust backlash or
pinion depth.
3. Unmatched ring gear and pinion. 3. Replace gears with a matched
ring gear and pinion.
4. Worn teeth on ring gear and/or
pinion.4. Replace ring gear and pinion.
5. Loose pinion bearings. 5. Adjust pinion bearing pre-load.
6. Loose differential bearings. 6. Adjust differential bearing
pre-load.
7. Mis-aligned or sprung ring gear. 7. Measure ring gear run-out.
Replace components as necessary.
8. Loose differential bearing cap
bolts.8. Inspect differential components
and replace as necessary. Ensure
that the bearing caps are torqued
tot he proper specification.
9. Housing not machined properly. 9. Replace housing.
KJREAR AXLE - 198RBI 3 - 53
REAR AXLE - 198RBI (Continued)
(10) Install axle vent hose.
(11) Install propeller shaft with reference marks.
(12) Install the wheels and tires.
(13) Add gear lubricant to specifications, if neces-
sary.
(14) Remove lifting device from axle and lower the
vehicle.
(15) Tighten the lower control arm bolts to torque
specification.
ADJUSTMENTS
ADJUSTMENT
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.
9). 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 96.850 mm (3.813 in.). The standard depth pro-
vides the best teeth contact pattern. Refer to Back-
lash and Contact Pattern Analysis Paragraph in this
section for additional information.
Compensation for pinion depth variance is
achieved with select shims. The shims are placed
under the inner pinion bearing cone (Fig. 10).
If a new gear set is being installed, note the depth
variance etched into both the original and replace-
ment pinion gear. Add or subtract the thickness of
the original depth shims to compensate for the differ-
ence in the depth variances. Refer to the Depth Vari-
ance charts.Note where Old and New Pinion Marking columns
intersect. Intersecting figure represents plus or
minus amount needed.
Note the etched number on the face of the drive
pinion gear (±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 shim(s). If the num-
ber is positive, subtract that value from the thickness
of the depth shim(s). If the number is 0 no change is
necessary. Refer to the Pinion Gear Depth Variance
Chart.
Fig. 8 LOWER SUSPENSION ARM
1 - AXLE BRACKET BOLT
2 - LOWER CONTROL ARM
3 - BODY BRACKET BOLTFig. 9 PINION GEAR ID NUMBERS
1 - PRODUCTION NUMBERS
2 - PINION GEAR DEPTH VARIANCE
3 - GEAR MATCHING NUMBER
Fig. 10 Shim Locations
1 - PINION GEAR DEPTH SHIM
2 - DIFFERENTIAL BEARING SHIM
3 - RING GEAR
4 - DIFFERENTIAL BEARING SHIM
5 - COLLAPSIBLE SPACER
KJREAR AXLE - 198RBI 3 - 55
REAR AXLE - 198RBI (Continued)
(24) Rotate dial indicator out of the way on pilot
stud.
(25) Remove differential case and dummy bearings
from the housing.
(26) Install new side bearing cones and cups on
differential case.
(27) Install spreader W-129-B and some compo-
nents of Adapter Set 6987 on differential housing and
spread axle opening enough to receive differential
case.
(28) Place side bearing shims into the housing
against the axle tubes.
(29) Install differential case in the housing.
(30) Rotate the differential case several times to
seat the side bearings.
(31) Position the indicator plunger against a ring
gear tooth (Fig. 22).
(32) Push and hold ring gear upward while not
allowing the pinion gear to rotate.
(33) Zero dial indicator face to pointer.
(34) Push and hold ring gear downward while not
allowing the pinion gear to rotate. Dial indicator
reading should be between 0.13-0.20 mm (0.005-0.008
in.). If backlash is not within specifications transfer
the necessary amount of shim thickness from one
side of the differential housing to the other (Fig. 23).
(35) 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 varymore than specified, the ring gear or the differential
case is defective.
After the proper backlash is achieved, perform the
Gear Contact Pattern Analysis procedure.
GEAR CONTACT PATTERN
The ring gear and pinion teeth contact patterns
will show if the pinion depth is correct in the hous-
ing. It will also show if the ring gear backlash has
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
squeeze 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
3 - 60 REAR AXLE - 198RBIKJ
REAR AXLE - 198RBI (Continued)