
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.
DIAGNOSTIC CHART
Condition Possible Causes Correction
Wheel Noise 1. Wheel loose. 1. Tighten loose nuts.
2. Faulty, brinelled wheel bearing. 2. Replace bearing.
Axle Shaft Noise 1. Misaligned axle tube. 1. Inspect axle tube alignment.
Correct as necessary.
2. Bent or sprung axle shaft. 2. Inspect and correct as necessary.
3. End-play in pinion bearings. 3. Refer to pinion pre-load
information and correct as
necessary.
4. Excessive gear backlash
between the ring gear and pinion.4. Check adjustment of the ring
gear and pinion backlash. Correct
as necessary.
5. Improper adjustment of pinion
gear bearings.5. Adjust the pinion bearings
pre-load.
6. Loose pinion yoke nut. 6. Tighten the pinion yoke nut.
7. Scuffed gear tooth contact
surfaces.7. Inspect and replace as
necessary.
Axle Shaft Broke 1. Misaligned axle tube. 1. Replace the broken shaft after
correcting tube mis-alignment.
2 Vehicle overloaded. 2. Replace broken shaft and avoid
excessive weight on vehicle.
3. Erratic clutch operation. 3. Replace broken shaft and avoid
or correct erratic clutch operation.
4. Grabbing clutch. 4. Replace broken shaft and inspect
and repair clutch as necessary.
KJFRONT AXLE - 186FIA 3 - 21
FRONT AXLE - 186FIA (Continued)

Condition Possible Causes Correction
Differential Cracked 1. Improper adjustment of the
differential bearings.1. Replace case and inspect gears
and bearings for further damage.
Set differential bearing pre-load
properly.
2. Excessive ring gear backlash. 2. Replace case and inspect gears
and bearings for further damage.
Set ring gear backlash properly.
3. Vehicle overloaded. 3. Replace case and inspect gears
and bearings for further damage.
Avoid excessive vehicle weight.
4. Erratic clutch operation. 4. Replace case and inspect gears
and bearings for further damage.
Avoid erratic use of clutch.
Differential Gears Scored 1. Insufficient lubrication. 1. Replace scored gears. Fill
differential with the correct fluid type
and quantity.
2. Improper grade of lubricant. 2. Replace scored gears. Fill
differential with the correct fluid type
and quantity.
3. Excessive spinning of one
wheel/tire.3. Replace scored gears. Inspect all
gears, pinion bores, and shaft for
damage. Service as necessary.
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.
3 - 22 FRONT AXLE - 186FIAKJ
FRONT AXLE - 186FIA (Continued)

REMOVAL
(1) Raise and support vehicle.
(2) Remove wheel and tire assemblies.
(3) Remove half shaft hub nuts.
(4) Remove lower control arms. Refer to 2 suspen-
sion for procedure.
(5) Remove half shafts.
(6) Remove skid plate.
(7) Remove differential drain plug (Fig. 3) and
drain fluid.
(8) Remove differential vent hose (Fig. 4) from
cover.
(9) Remove propeller shaft from pinion flange.
(10) Support axle with a lift/jack.
(11) Remove bolt from left front axle bracket frame
mount (Fig. 5).
(12) Remove bolts from right axle bracket frame
mounts (Fig. 6).
(13) Remove bolt from left rear axle bracket frame
mount (Fig. 7).
(14) Lower axle from vehicle.
(15) Remove brackets from axle if necessary.
INSTALLATION
(1) Install left rear bracket to axle and tighten to
61 N´m (45 ft. lbs.).
(2) Install right bracket to axle and tighten to 88
N´m (65 ft. lbs.).(3) Install left front bracket to axle and tighten to
61 N´m (45 ft. lbs.).
(4) Raise axle up and align brackets with frame
mounts.
(5) Install frame mount bolts and tighten to 88
N´m (65 ft. lbs.).
(6) Install propeller shaft.
(7) Install half shafts.
Fig. 3 DRAIN PLUG
1 - LEFT FRONT AXLE BRACKET
2 - DRAIN PLUG
3 - DIFFERENTIAL HOUSING
Fig. 4 DIFFERENTIAL COVER
1 - COVER
2 - VENT TUBE
Fig. 5 LEFT FRONT AXLE BRACKET
1 - LEFT FRONT AXLE BRACKET
2 - BRACKET BOLT
3 - 24 FRONT AXLE - 186FIAKJ
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)

AXLE SHAFTS
REMOVAL
(1) Place the transmission in Neutral.
(2) Raise and support vehicle.
(3) Remove right wheel and tire and assembly.
(4) Remove right half shaft from vehicle.
(5) Remove snap ring from axle shaft.
(6) Assemble Remover 8420A onto the shaft (Fig.
25). Thread slid hammer into remover and remove
shaft.
(7) Slide axle shaft out of the axle tube.
NOTE: Use care to prevent damage to axle shaft
bearing and seal, which will remain in axle shaft
tube.
INSTALLATION
(1) Lubricate bearing bore and seal lip with gear
lubricant. Insert axle shaft through seal, bearing
(Fig. 26) and engage it into side gear splines.
NOTE: Use care to prevent shaft splines from dam-
aging axle shaft seal.
(2) Push on the axle shaft until the axle shaft
snap-ring passes through the side gear.
(3) Install right half shaft.
(4) Install right wheel and tire assembly.
(5) Check differential fluid level.
(6) Lower vehicle.
AXLE SHAFT SEALS
REMOVAL
(1) Remove half shaft.
(2) Remove axle shaft for right side seal removal.
(3) Remove shaft seal with Remover 7794-A and a
slide hammer (Fig. 27).
Fig. 25 AXLE SHAFT PULLER
1 - SNAP RING GROVE
2 - SLID HAMMER THREADS
3 - REMOVER BLOCKS
4 - REMOVER COLLAR
Fig. 26 AXLE SHAFT SEAL
1 - BEARING
2 - SEAL
Fig. 27 SHAFT SEAL REMOVER
1 - SHAFT SEAL
2 - REMOVER
KJFRONT AXLE - 186FIA 3 - 37

INSTALLATION
(1) Apply a light coat of lubricant on the lip of the
shaft seal.
(2) Installnewshaft seal with Installer 8806 and
Handle C-4171 (Fig. 28).
(3) Install right axle shaft if removed.
(4) Install half shaft.
AXLE BEARINGS
REMOVAL
(1) Remove half shaft.
(2) Remove axle shaft for right side seal removal.
(3) Remove shaft seal with Remover 7794-A and a
slide hammer.
(4) Remove shaft bearing with Remover 7794-A
and a slide hammer (Fig. 29).
INSTALLATION
(1) Installnewshaft bearing with Installer 8805
and Handle C-4171.
(2) Apply a light coat of lubricant on the lip of the
shaft seal.
(3) Installnewshaft seal with an appropriate
installer.
(4) Install right axle shaft if removed.
(5) Install half shaft.
PINION SEAL
REMOVAL
(1) Raise and support the vehicle.
(2) Remove wheel and tire assemblies.
(3) Remove brake calipers and rotors, refer to 5
Brakes for procedures.
(4) Mark propeller shaft and pinion companion
flange for installation reference.
(5) Remove propeller shaft from the pinion com-
panion flange.
(6) Rotate pinion gear a minimum of ten times and
verify the pinion rotates smoothly.
(7) Record the torque to rotate the pinion gear
(Fig. 30) with a inch pound torque wrench.
Fig. 28 SEAL INSTALLER
1 - SEAL BORE
2 - INSTALLER
Fig. 29 SHAFT BEARING REMOVER
1 - SHAFT BEARING
2 - REMOVER
Fig. 30 PINION ROTATING TORQUE
1 - PINION COMPANION FLANGE
2 - TORQUE WRENCH
3 - 38 FRONT AXLE - 186FIAKJ
AXLE SHAFT SEALS (Continued)

(4) Rotate pinion a minimum of ten time and ver-
ify pinion rotates smoothly. Rotate the pinion shaft
with an inch pound torque wrench. Rotating torque
should be equal to the reading recorded during
removal plus 0.56 N´m (5 in. lbs.) (Fig. 35).
(5) If the rotating torque is low, use Spanner
Wrench 6958 to hold the pinion companion flange
and tighten the pinion shaft nut in 6.8 N´m (5 ft.
lbs.) increments until proper rotating torque is
achieved.
CAUTION: If maximum tightening torque is reached
prior to reaching the required rotating torque, the
collapsible spacer may have been damaged.
Replace the collapsible spacer.
(6) Install propeller shaft with installation refer-
ence marks aligned.
(7) Fill differential with gear lubricant.
(8) Install brake rotors and calipers.
(9) Install wheel and tire assemblies.
(10) Lower the vehicle.
DIFFERENTIAL
REMOVAL
(1) Remove axle from the vehicle.
(2) Remove differential housing cover (Fig. 36).
(3) Push right axle shaft out of side gear (Fig. 37)
and remove the shaft.
(4) Mark differential bearing caps for installation
reference.
(5) Loosen the bearing cap bolts.
Fig. 35 PINION ROTATING TORQUE
1 - PINION COMPANION FLANGE
2 - TORQUE WRENCHFig. 36 DIFFERENTIAL COVER
1 - COVER
2 - VENT TUBE
Fig. 37 RIGHT SHAFT IN SIDE GEAR
1 - AXLE SHAFT
2 - SCREWDRIVER
3 - SIDE GEAR
3 - 40 FRONT AXLE - 186FIAKJ
PINION SEAL (Continued)

rear propeller shaft is connected to the pinion gear
which rotates the 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 pin-
ion 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
pinion mate shaft but do not rotate around it (Fig. 2).
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.
3). 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.
TRAC-LOKŸ DIFFERENTIAL
The Trac-lokŸ clutches are engaged by two concur-
rent forces. The first being the preload force exerted
through Belleville spring washers within the clutch
packs. The second is the separating forces generated
by the side gears as torque is applied through the
ring gear (Fig. 4).
Fig. 2 DIFFERENTIAL-STRAIGHT AHEAD DRIVING
1 - IN STRAIGHT AHEAD DRIVING EACH WHEEL ROTATES AT
100% OF CASE SPEED
2 - PINION GEAR
3 - SIDE GEAR
4 - PINION GEARS ROTATE WITH CASE
Fig. 3 DIFFERENTIAL-ON TURNS
1 - PINION GEARS ROTATE ON PINION SHAFT
Fig. 4 TRAC-LOK DIFFERENTIAL
1 - CASE
2 - RING GEAR
3 - DRIVE PINION
4 - PINION GEAR
5 - MATE SHAFT
6 - CLUTCH PACK
7 - SIDE GEAR
8 - CLUTCH PACK
3 - 50 REAR AXLE - 198RBIKJ
REAR AXLE - 198RBI (Continued)