Front axle JEEP CHEROKEE 1994 Service Workshop Manual

original depth shims to compensate for the dif-
ference in the depth variances. Refer to the
Depth Variance charts.
Note where Old and New Pinion Marking columns
intersect. Intersecting figure represents plus or mi-
nus amount needed.
For example, if old pinion is plus (+) 1 and the
new pinion is minus (-) 3, intersecting figure is
(+)0.004 inch (0.10mm). Add this amount to the
original shim. Or if the old pinion is (-) 3 and thenew pinion is (-) 2, intersecting figure is (-)0.001 inch
(0.025mm). Subtract this amount from original shim.
Refer to the Pinion Gear Depth Variance Chart.
DIFFERENTIAL AND PINION MEASUREMENT
DIFFERENTIAL ZERO END PLAY
MEASUREMENT
(1) Place Master Differential Bearing D-134
(D-348) on the case hubs (Fig. 43) and install differ-
ential case into housing.
(2) Install a pilot stud at the right side of housing.
Attach Dial Indicator to the pilot stud. Load indica-
tor plunger against the back of the ring gear (Fig.
44).
(3) Insert a small pry bar between the bearing cap
and left side of differential case. Pry the case as far
as possible to right side (Fig. 44). Zero the dial indi-
cator pointer.
(4) Pry the case to left side andrecordthe travel
distance.
The measurement above is the shim thickness
necessary for case zero end-play. The total
thickness will be determined during the ring
gear backlash adjustment.
(5) Remove indicator, pilot stud and differential
case from housing.
PINION GEAR DEPTH MEASUREMENT
Pinion gear depth measurement is necessary
when axle housing is replaced or pinion select
shim pack is unknown. It is also recommended
when ring and pinion gears are replaced.
PINION GEAR DEPTH VARIANCE
Fig. 42 Shim Locations
2 - 38 FRONT SUSPENSION AND AXLEJ

Measurements are done with pinion cups and pin-
ion bearings installed in housing. Take measure-
ments with Pinion Gauge Set 6774, Pinion Block
6733 and Dial Indicator C-3339 (Fig. 45).
(1) Assemble Pinion Gauge Set, Pinion Block and
pinion bearings. Install assembly into differential
pinion gear bore and hand tighten cone (Fig. 46).
(2) Place Arbor Disc 6732 on Arbor D-115-3 and
position in the bearing cradles (Fig. 47). Install dif-
ferential bearing caps on Arbor Discs and tighten
caps snug only.
Fig. 45 Pinion Gear Depth Gauge Tools
Fig. 46 Pinion Height Block
Fig. 47 Gauge Tools In Housing
Fig. 43 Master Bearing Tools On Hubs
Fig. 44 Differential Case End Play Measurement
JFRONT SUSPENSION AND AXLE 2 - 39

Arbor Discs have different steps to fit other
axle sizes. Pick correct size step for axle being
serviced.
(3) Firmly place Scooter Block and Dial Indicator
on pinion height block tool and zero the dial indica-
tor pointer.
(4) Slide the Scooter Block across the arbor while
observing indicator (Fig. 48). Record the longest
travel distance, whether inward (-) or outward (+),
indicated by the pointer.
The plunger travel distance indicated, plus or
minus the variance etched in the gear is the re-
quired thickness for the depth shims.
(5) Measure the thickness of each depth shim with
a micrometer and combine the shims necessary fortotal required shim pack thickness.Include oil
slinger or baffle thickness with the total shim
pack thickness.
(6) Remove the measurement tools from the differ-
ential housing.
PINION GEAR ASSEMBLY/INSTALLATION
(1) Place the shims (and baffle if equipped) in the
pinion gear rear bearing bore. Install the bearing cup
with Installer D-146 and Driver Handle C-4171 (Fig.
49). Ensure cup is correctly seated.
(2) Install the pinion front bearing cup with In-
staller D-144 and Handle C-4171 (Fig. 50).
(3) Install the rear bearing and oil slinger on the
pinion gear with Installer W-262 until completely
seated (Fig. 51).
Fig. 48 Pinion Depth Measurement
Fig. 49 Pinion Rear Bearing Cup Installation
Fig. 50 Pinion Front Bearing Cup Installation
Fig. 51 Pinion Rear Bearing Installation
2 - 40 FRONT SUSPENSION AND AXLEJ

(4) Assemble collapsible spacer onto pinion shaft
(Fig. 52).
(5) Install pinion front bearing cone into cup and
end yoke thrust washer.
(6) Apply a light coat of gear lubricant on lip of
new pinion seal. Install seal with Installer W-147-E
and Handle C-4171 (Fig. 53).
(7) Install pinion gear into differential housing.
(8) Install yoke with Installer W-162-D and
Wrench C-3281 (Fig. 54).(9) Install the yoke washer and a new nut on the
pinion gear. Use Flange Wrench C-3281 to retain the
yoke (Fig. 55). Tighten nut to 216 Nzm (160 ft.lbs.)
torque or enough to remove play.Do not over-
tighten.
CAUTION: Never loosen the pinion gear nut to de-
crease the pinion gear bearing preload torque. If the
specified preload torque is exceeded, a new col-
lapsible spacer must be installed. The torque se-
quence will have to be repeated.
Fig. 52 Collapsible Preload Spacer
Fig. 53 Pinion Seal Installation
Fig. 54 Pinion Yoke Installation
Fig. 55 Tightening Pinion Nut
JFRONT SUSPENSION AND AXLE 2 - 41

(10) Use Flange Wrench C-3281 to retain the yoke
(Fig. 55). Slowly tighten the nut in small increments
until the rotating torque is achieved. Measure the ro-
tating torque frequently to avoid over-tightening the
nut.
(11) Check bearing rotating torque with an inch
pound torque wrench (Fig. 56). The torque necessary
to rotate the pinion gear should be;
²Original Bearings Ð 1 to 3 Nzm (10 to 20 in. lbs.).
²New BearingsÐ2to5Nzm (15 to 35 in. lbs.).
DIFFERENTIAL SHIM PACK MEASUREMENT AND
ADJUSTMENT
(1) Place Master Differential Bearing D-134
(D-348) on the case hubs.
(2) Install a pilot stud at the left side of housing.
Attach Dial Indicator to housing. Load the indicator
plunger against the back of the ring gear (Fig. 57).
Ensure ring and pinion gear teeth are tightly
meshed. Zero the indicator.
(3) Insert a small pry bar between the bearing cap
and left side of differential case. Pry the case as far
as possible to right side (Fig. 57). Zero the dial indi-
cator pointer.
(4) Repeat the measurement several times to check
consistency. Record the travel distance.
The measurement above shows shim thickness
necessary to eliminate ring gear backlash. Sub-
tract this thickness from case zero end-play
shim thickness (Fig. 58). The shims must be
placed at the ring gear side between the case
and bearing.
(5) Remove indicator and pilot stud.
(6) Remove the differential case from housing.(7) Remove the master bearing tools from the dif-
ferential case hubs.
(8) Position the backlash shims (with determined
thickness) on case hub (ring gear side). Install bear-
ing on the hub with Bearing Installer C-3716-A and
Driver Handle C-4171 (Fig. 59).
(9) Position the remaining zero end-play shims on
hub at opposite side of case. Include an additional
Fig. 56 Check Pinion Gear Torque
Fig. 57 Shim Pack Measurement
Fig. 58 Shim Pack Calculations
2 - 42 FRONT SUSPENSION AND AXLEJ

0.015 in. (0.38 mm) thick shim on this hub. This will
provide the required differential bearing preload
torque.
(10) Install bearings on hubs with Installer
C-3716-A and Handle C-4171 (Fig. 59).
(11) Match each bearing cup with bearing (origi-
nal). Install the cups on the bearings.
DIFFERENTIAL INSTALLATION
(1) Position Spreader W-129-B with the tool dowel
pins seated in the locating holes (Fig. 60). Install the
holddown clamps and tighten the tool turnbuckle fin-
ger-tight.
(2) Install a pilot stud at the left side of the differ-
ential housing. Attach Dial Indicator to housing pilotstud. Load the indicator plunger against the opposite
side of the housing (Fig. 60) and zero the indicator.
CAUTION: Do not spread over 0.38 mm (0.015 in). If
the housing is over-separated, it could be distorted
or damaged.
(3) Spread the housing enough to install the case
in the housing. Measure the distance with the dial
indicator (Fig. 60).
(4) Remove the dial indicator.
(5) Install case in the housing. Tap the differential
case to ensure the bearings are fully seated (Fig. 61).
Remove the spreader.
(6) Install the bearing caps at their original loca-
tions (Fig. 62). Tighten the bearing cap bolts to 61
Nzm (45 ft. lbs.) torque.
Fig. 59 Differential Bearing Installation
Fig. 60 Spread Differential Housing
Fig. 61 Differential Installation
Fig. 62 Differential Bearing Cap Reference Letters
JFRONT SUSPENSION AND AXLE 2 - 43

BACKLASH AND CONTACT PATTERN ANALYSIS
(1) Rotate assembly several revolutions to seat
bearings. Measure backlash at three equally spaced
locations around the perimeter of the ring gear with
a dial indicator (Fig. 63).
The ring gear backlash must be within 0.005 -
0.008 inch (0.12 - 0.20 mm). It cannot vary more
than 0.002 inch (0.05 mm) between the points
checked.
If backlash must be adjusted, transfer shims from
one side of carrier to the other side. Adjust the back-
lash accordingly (Fig. 64).DO NOT INCREASE
THE TOTAL SHIM PACK THICKNESS, EXCES-
SIVE BEARING PRELOAD AND DAMAGE
WILL OCCUR.If the mesh and backlash steps have been followed
in the procedures above, good gear teeth contact pat-
terns should exist.
The ring gear teeth contact patterns will show if
the pinion gear depth is correct. It will also show if
the ring gear backlash has been adjusted correctly.
The backlash must be maintained within the speci-
fied limits until the correct tooth contact patterns are
obtained.
(2) Apply a thin coat of hydrated ferric oxide (yel-
low oxide of iron) to the drive and coast side of the
ring gear teeth.
(3) Rotate the ring gear one complete revolution in
both directions while a load is being applied. Insert a
pry bar between the differential housing and the case
flange. This action will produce distinct contact pat-
terns on both the drive side and coast side of the ring
gear teeth.
(4) Note patterns in compound. Refer to (Fig. 65)
for interpretation of contact patterns and adjust ac-
cordingly.
FINAL ASSEMBLY
(1) Install the axle shafts. Refer to Axle Shaft In-
stallation in this Group.
(2) Scrape the residual sealant from the housing
and cover mating surfaces. Clean the mating sur-
faces with mineral spirits. Apply a bead of MOPARt
Silicone Rubber Sealant on the housing cover (Fig.
66). Allow the sealant to cure for a few minutes.
Install the housing cover within 5 minutes af-
ter applying the sealant. If not installed the seal-
ant must be removed and another bead applied.
(3) Install the cover on the differential with the at-
taching bolts. Install the identification tag. Tighten
the cover bolts with 41 Nzm (30 ft. lbs.) torque.
CAUTION: Overfilling the differential can result in
the lubricant foaming and overheating.
(4) Refill the differential housing with the speci-
fied quantity of MOPARtHypoid Gear Lubricant.
(5) Install the fill hole plug and tighten to 34 Nzm
(25 ft. lbs.) torque.Fig. 63 Ring Gear Backlash Measurement
Fig. 64 Backlash Shim Adjustment
2 - 44 FRONT SUSPENSION AND AXLEJ

Fig. 65 Gear Tooth Contact Patterns
JFRONT SUSPENSION AND AXLE 2 - 45

AXLE SPECIFICATIONS
Fig. 66 Typical Housing Cover With Sealant
MODEL 30 FRONT AXLE
2 - 46 FRONT SUSPENSION AND AXLEJ

TORQUE SPECIFICATIONS
XJ FRONT SUSPENSION COMPONENTS
YJ FRONT SUSPENSION COMPONENTS
MODEL 30 AXLE
JFRONT SUSPENSION AND AXLE 2 - 47