front diff JEEP CHEROKEE 1988 Service Repair Manual

ROD BEARING
NOTE: Crankshaft journal diameters are indicated by a color coded
mark placed on the adjacent counterweight or cheek toward
the flanged (rear) end of crankshaft. Note color code to
determine proper bearing usage. Check oil clearance after
bearing installation.
Removal
Remove oil pan. See OIL PAN REMOVAL at end of ENGINE section.
Rotate crankshaft to position rod to be serviced at bottom of stroke.
Mark bearing cap and connecting rod. Remove bearing cap with bearing.
Push piston and rod assembly up to remove upper bearing.
Installation
1) Note color code on edge of bearings removed. Install
bearings. Using Plastigage method, check bearing clearances. Replace
bearings as necessary to obtain correct clearance. Bearings are
available in standard and undersize application.
2) If required, different sized upper and lower bearings may
be installed to obtain correct oil clearance. Tighten bolts to
specification. Check rod side play. Rotate crankshaft to ensure
freedom of movement. Reverse removal procedure for remaining
components. Tighten bolts to specification.
NOTE: Avoid combining bearing inserts in excess of .001" (.02 mm)
difference in size.
MAIN BEARING
Removal
Remove oil pan. See OIL PAN REMOVAL at end of ENGINE section.
Ensure main bearing caps are marked for location. Remove bearing cap.
Rotate crankshaft to remove bearings. Note color code on edge of
bearing.
NOTE: Crankshaft main bearing journal diameters are indicated by a
color code. Color code is placed on the adjacent cheek
toward the flanged (rear) end of crankshaft for all except
the rear main. Rear main is color coded on the rear flange.
Note color code to determine proper bearing usage. Check oil
clearance after bearing installation.
Installation
1) Note color code on edge of bearings removed. Install
bearings. Ensure caps are installed in original location with arrow on
cap facing toward front of engine. Using Plastigage method, check
bearing clearances.
2) Replace bearings as necessary to obtain correct clearance.
Bearings are available in standard and undersize applications. If
required, different sized upper and lower bearings may be installed to
obtain correct oil clearance.
NOTE: If different sized bearings are used, odd sized bearings must
all be uniform in location (upper or lower). DO NOT use
bearings with a thickness difference exceeding
.001" (.02 mm).
3) Tighten bolts to specification. Check crankshaft end play.
See CRANKSHAFT END PLAY in this article. Rotate crankshaft to ensure
freedom of movement. Reverse removal procedure for remaining
components. Tighten bolts to specification.

Fig. 2: Exploded View of Split Case (4-Pinion)
2) Drive vehicle over formica board until one rear wheel is
in the center of board and paper. Place a block of wood 2" high and a
minimum of 3" wide in front of one of the front wheels.
3) Open throttle gradually attempting to slowly drive vehicle
over block of wood. If paper slips out of position, reposition paper
and repeat test. If vehicle drives over block of wood, axle is
functioning properly.
DANA 4-PINION POWER-LOK
1) With engine off and transmission in "N", raise one wheel
off ground. Block both front and rear wheels of opposite side. Install
adapter tool across 2 wheel studs and attach torque wrench to center
of tool.
2) Observe torque required to continuously turn wheel
smoothly through several revolutions. Repeat test for opposite side.
If differential is okay, torque should be 40-200 ft. lbs. (54-272 N.
m). Disregard breakaway torque. Use rotating torque only.
NOTE: Exploded view of Chrysler Motors Trac-Lok differential was
not available from manufacturer.
REMOVAL & INSTALLATION
See DANA SEMI-FLOATING or FULL-FLOATING AXLE article in this
section.
OVERHAUL
DANA 2-PINION TRAC-LOK
NOTE: For front axle shaft and bearing removal, see articles on
DANA FULL-FLOATING AXLES or 4WD STEERING KNUCKLES in this
section. With the exception of ring gear and differential
side bearings, Chrysler Motors does not recommend disassembly
of differential. If repair is required, manufacturer
recommends replacing entire unit as an assembly.
Disassembly (Jeep)
1) Using 2 screwdrivers, remove pinion snap rings. Using a
brass drift and a hammer, remove pinion shaft from case. Install Step

\003
DRIV E A XLE - F U LL F LO ATIN G

1988 J e ep C hero ke e
Drive Axles - Dana Full-Floating Axles
Jeep Front & Rear Drive Axles
DESCRIPTION
The axle assembly is an integral carrier type with hypoid
gear ring and pinion. Stamped steel cover is removable for inspection
and repair of differential. Vehicle loads are carried by axle
housings. Axle shafts of "full-floating" rear assemblies may be
removed without disturbing wheel bearings.
Drive pinion depth, pinion bearing preload and differential
side bearing preload are all set by shims.
See LOCKING HUB and 4WD STEERING KNUCKLE articles in this
section for removal and installation procedures for these front drive
axle component parts.
AXLE RATIO & IDENTIFICATION
A metal tag on axle is stamped with gear ratio, part numbers
and limited slip identification. To determine drive axle ratio, refer
to MODEL IDENTIFICATION BY RING GEAR SIZE table.
MODEL IDENTIFICATION BY RING GEAR SIZE









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Model Ring Gear Diameter
44 ....................................... 8.50"
60 ....................................... 9.75"
61 ....................................... 9.75"
70 ...................................... 10.50"
80 ...................................... 11.25"









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FRONT HUB, BEARING, SPINDLE & AXLE SHAFT R & I
FRONT HUB BEARING ADJUSTING SPECIFICATIONS








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Application ( 1) Ft. Lbs. (N.m)
Adjusting Nut
Step 1 ............................... 50 (68)
Step 2 .......................... Back Off 20

Lock Nut ............................... 50 (68)
( 1) - While Rotating Hub.









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REMOVAL (CHEROKEE, COMANCHE & WAGONEER)
1) Raise and support vehicle. Remove tire and wheel assembly.
Remove disc brake caliper and support out of way.
2) Match mark disc rotor and hub and remove disc rotor.
Remove cotter pin, nut lock and axle hub nut. Remove hub-to-knuckle
bolts. Pull hub assembly off axle shaft. Pull axle shaft through
knuckle to remove. Inspect axle shaft "U" joint and shaft splines for
wear. Replace as necessary.
3) Press hub out of bearings. Remove seals and bearings.

REMOVAL
1) Raise and support vehicle. Remove wheels, hubs and axles.
See REAR HUB, BEARINGS AND AXLE SHAFTS.
2) Remove lower shock mounts and stabilizer bar mount.
Disconnect drive shaft and tie up. Remove hydraulic brake line at
junction and plug.
3) Disconnect park brake cables and hydraulic brake lines to
wheel cylinders or calipers. Remove brake backing plate or caliper.
4) Support axle housing with floor jack and remove leaf
spring "U" bolts. Carefully lower axle housing and remove from
vehicle.
INSTALLATION
Place axle housing on floor jack. Raise axle and install "U"
bolts and nuts. To complete installation, reverse removal procedure.
Tighten all bolts and nuts to specification. See TORQUE SPECIFICATIONS
table at the end of this article and REAR HUB BEARING ADJUSTING
SPECIFICATIONS table.
PINION SEAL & YOKE R & I
REMOVAL
1) Raise and support vehicle. Mark drive shaft-to-yoke
contact area for reassembly reference. Remove drive shaft-to-yoke
attaching nuts/strap bolts. Discard used strap bolts. Remove drive
shaft.
2) Using a breaker bar and Pinion Nut Remover (8614-01),
remove pinion nut and washer. See Fig. 3. Using Yoke Pullers (8614-
01), (8614-02) and (8614-03), remove yoke. See Fig. 4. Using Pinion
Seal Remover (J-9233 or J-7583), remove pinion seal from front
differential housing. See Fig. 5.
Fig. 3: Removing Pinion Nut & Washer

Fig. 5: Removing Pinion Seal
INSTALLATION
Using Seal Installer (J22661), drive new seal into front
differential housing. See Fig. 6. Tighten yoke attaching nut to 210
ft. lbs. (285 N.m). Using NEW strap bolts, align and install drive
shaft. Tighten strap bolts to 14 ft. lbs. (19 N.m). Fill differential
with SAE 75W-90 gear lubricant.

closer to pinion gear. If backlash is too low, move ring gear away
from pinion gear.
3) To change backlash readings, move shims from one side of
differential case to other. When backlash adjustment is completed,
check tooth contact pattern. See GEAR TOOTH CONTACT PATTERNS in this
section. Pattern should be correct if assembly and adjustments have
been done properly.
4) When differential is complete and correctly adjusted,
install new cover gasket and cover. Tighten cover bolts to 30-40 ft.
lbs. (41-54 N.m). Fill assembly with hypoid lubricant.
AXLE ASSEMBLY SPECIFICATIONS TABLE









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Application Specifications In. (mm)
Pinion Gear Depth (Nominal Dimension)
Model 44 ................................. 2.625 (66.68)
Model 60 & 61 ............................ 3.125 (79.38)
Model 70 & 80 ............................ 3.500 (88.90)
Ring Gear Backlash ................... .004-.009 (.10-.23)
Side Bearing Preload .......................... .015 (.38)
INCH lbs. (N.m)
Pinion Bearing Preload
New Bearings ........................... 20-40 (2.3-4.5)
Used Bearings .......................... 10-20 (1.1-2.3)









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TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE








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Applications Ft. Lbs. (N.m)
Axle Flange-to-Hub Bolt
Model 44 ...................................... 35 (48)
Models 60 & 61 ................................ 55 (75)
Model 70 & 80 ................................ 85 (115)
Pinion Shaft Flange Nut
Models 44 & 70 .............................. 210 (285)
Models 60 & 61 .............................. 270 (367)
Model 80 ............................ 440-500 (597-678)
Ring Gear-to-Case Bolt
Model 44 ...................................... 55 (75)
Models 60, 61, & 70 ......................... 110 (149)
Model 80 ............................ 145-165 (196-223)
Side Bearing Cap Bolt ........................... 80 (108)
Front Axle
Cherokee, Comanche, & Wagoneer
Axle Shaft Nut ............................. 175 (237)
Disconnect Housing Bolt ...................... 10 (14)
Hub-to-Knuckle Bolt ......................... 75 (102)
Lower Control Arm Bolt ..................... 133 (180)
Lower Shock Mount Bolt ....................... 14 (19)
Drive Shaft Bolt ............................. 14 (19)
Stabilizer Bar Link Bolt ..................... 70 (95)
Tie Rod Nut ............................ 25-45 (34-61)
Upper Control Arm Bolt ....................... 37 (50)
Wheel Lug Nut ............................... 75 (102)
Grand Wagoneer
Leaf Spring "U" Bolt Nut ................... 100 (136)
Lower Shock Mount Bolt ....................... 45 (61)

perform overhaul.
1) Raise and support rear of vehicle. Remove rear cover and
drain lubricant. Remove wheels, brake drums, hubs and axle shafts.
2) Mark differential bearing caps for reassembly reference
and loosen them until a few threads remain engaged. Pry differential
loose and remove bearing caps and differential from housing.
3) Mark bearing caps, races and shims for reassembly
reference. Remove differential side bearings with a puller. Remove
differential and ring gear from case. Remove pinion shaft lock pin.
4) Using 2 feeler gauges, measure differential side gear
clearance. Insert an equal distance feeler gauge between each side
gear and case. Continue checking clearance until each feeler gauge is
a tight drag fit. Ensure side clearance does not exceed .007" (.18 mm)\
on either side. If side gear clearance exceeds specification, replace
side gear thrust washers.
5) Remove pinion yoke and nut. Retain pinion nut for pinion
depth adjustment during reassembly. Tap pinion gear end with a soft
faced mallet to release it from front bearing. Remove pinion gear,
pinion bearings and preload collapsible spacer. Discard collapsible
spacer.
6) Remove pinion seal and pinion rear bearing cup. Remove and
retain pinion depth shim located under rear bearing cup. Remove pinion
front bearing cup. Using a press, remove pinion gear rear bearing.
CLEANING & INSPECTION
Clean all components in solvent and dry with compressed air.
Inspect all components for excessive wear or damage and replace as
necessary.
REASSEMBLY
NOTE: Ensure correct shims have been chosen to obtain proper
ring gear backlash and bearing preload before reassembly.
See ADJUSTMENTS in this article.
Drive Pinion
1) Press rear bearing on pinion stem with large diameter of
roller cage toward gear. Clean housing bearing bores. Place shim in
rear bearing bore and install rear bearing cup.
NOTE: When installing a new gear set, use original depth shim as a
starting point. Chamfered side of shim must be installed to
bottom side of rear bearing cup bore.
2) Install front bearing cup into housing. Install drive
pinion through rear bearing cup. Install front bearing, yoke and
original pinion nut. Tighten nut to remove bearing end play only.
NOTE: A new nut and collapsible spacer are not installed at this
time, as pinion will be removed after a depth measurement.
Differential Case
1) Assemble side gears and thrust washers and install into
differential case. Ensure side gear thrust washers were replaced in
clearance measured at disassembly was greater than .007" (.18 mm).
2) Install differential pinions and thrust washers in case.
Ensure pinions are aligned with shaft bores. Recheck side gear
clearance. If clearance exceeds .007" (.18 mm), side gears must be
replaced.
3) Install differential pinion shaft and lockpin. Using
Remover (J-22912-01), remove differential bearings. Install correct

article and determine amount to be added or subtracted from original
shim thickness to obtain starter shim thickness. DO NOT use starter
shim thickness as a final shim setting.
6) Install rear bearing on pinion gear. On heavy duty rear
axle, large end of bearing faces gear end of pinion. Press bearing
against rear face of gear.
7) On all axles, clean pinion bearing bores in axle housing
to ensure accurate measurement. Install and center starter shim in
housing bearing cup bore. If shim is chamfered, ensure chamfered side
faces bottom of bearing cup bore.
8) Install pinion rear and front bearing cups. Install pinion
gear in rear bearing cup and install pinion front bearing and yoke on
pinion gear. DO NOT install oil seal or collapsible spacer at this
time. Install and tighten original pinion nut only enough to remove
end play. Determine depth variance marked on pinion gear.
9) Install Arbor (J-5223-4) and Discs (J-5223-23) in
differential bearing cup bores. Ensure discs are fully seated in
bearing cup bores. Install bearing caps over discs and install bearing
cap bolts. Tighten bolts, but not to specified torque.
10) Position Gauge Block (J-5223-20) against end of drive
pinion with Clamp (J-5223-24) and Bolt (J-5223-29). See Fig. 4. Extend
clamp bolt until it presses against gauge block enough to prevent
gauge block from moving.
11) Loosen thumbscrew in end of gauge block to allow plunger
to contact arbor. When plunger contacts arbor, tighten thumbscrew,
taking care not to disturb plunger position.
12) Remove gauge block and measure distance from end of anvil
to top of plunger head, using a 2-3" (51-76 mm) micrometer. Record
this measured pinion depth for future reference.
13) Remove gauging tools, drive pinion and rear bearing cup.
Remove drive pinion depth shim and record thickness. Add shim
thickness to measured pinion depth. From this total subtract desired
pinion depth. For an example, see DETERMINING CORRECT SHIM THICKNESS
table.
DETERMINING CORRECT SHIM THICKNESSES









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Application In. (mm)
Standard Drive Axle
Standard Pinion Depth .............................. 2.095 (53.21)\
Pinion Depth Variance ............................... - .004 (.10)\
Desired Pinion Depth .............................. =2.091 (53.11)\
Measured Pinion Depth .............................. 2.100 (53.34)\
Starting Shim Thickness ............................ + .096 (.096)\
Total Measured Thickness Depth .................... =2.196 (55.77)\
Total Measured Pinion Depth ........................ 2.196 (55.77)\
Desired Pinion Depth .............................. -2.091 (53.11)\
Correct Shim Thickness .............................. =.105 (2.66)\
Heavy Duty Drive Axle
Standard Pinion Depth .............................. 2.547 (64.69)\
Pinion Depth Variance ............................... + .007 (.18)\
Desired Pinion Depth .............................. =2.554 (64.87)\
Measured Pinion Depth .............................. 2.550 (64.77)\
Starting Shim Thickness ............................. +.098 (2.49)\
Total Measured Pinion Depth ....................... =2.648 (67.26)\
Total Measured Pinion Depth ........................ 2.648 (67.26)\
Desired Pinion Depth .............................. -2.554 (64.87)\
Correct Shim Thickness .............................. =.094 (2.39)\









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14) The result represents correct shim thickness to be
installed. Install correct thickness shim in rear bearing bore and

AXLE ASSEMBLY SPECIFICATIONS TABLE








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Application Specification
Axle Shaft End Play ........................ .004-.008" (.10-.20 mm)\
Differential Bearing Preload ........................ .008" (.20 mm)\
Differential Case Face Runout ....................... .002" (.05 mm)\
Differential Side Gear Case Clearance ........... 0-.007" (0-.18 mm)\
Oil Capacity
Standard Drive Axle .............................. 2.5 pts. (1.2L)\
Heavy Duty Drive Axle ............................. 4.7 pts (2.2L)\
Pinion Bearing Preload ................... 15-25 INCH lbs. (2.3 N.m)\
Pinion Gear Depth (Standard)
Standard Drive Axle ............................ 2.095" (53.21 mm)\
Heavy Duty Drive Axle ........................... 2.547" (64.7 mm)\
Ring Gear
Backlash ................................. .005-.009" (.13-.23 mm)\
Preferred ......................................... .008" (.20 mm)\









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TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE








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Application Ft. Lbs. (N.m)
Axle Housing Cover ......................................... 14 (19)\
Axle-to-Leaf Spring "U" Bolts .............................. 52 (70)\
Brake Support Plate Bolts .................................. 32 (43)\
Differential Bearing Bolts
Standard Drive Axle ...................................... 57 (77)\
Heavy Duty Drive Axle ................................... 85 (115)\
Rear Axle Filler Plug
Standard Drive Axle ...................................... 25 (34)\
Heavy Duty Drive Axle .................................... 15 (20)\
Rear Spring Front Bolt ................................... 111 (150)\
Rear Spring Rear Shackle Nuts ............................ 111 (150)\
Ring Gear Bolts
Standard Drive Axle ............................... 70-90 (95-122)\
Heavy Duty Drive Axle .................................. 105 (142)\
Shock Absorber-to-Axle Nut ................................. 44 (60)\
Universal Joint Clamp Strap Bolts .......................... 14 (19)\
Wheel Lug Nuts ............................................ 75 (102)\









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PINION DEPTH SHIM ADJUSTMENT SPECIFICATIONS
PINION DEPTH SHIM ADJUSTMENT CHART (INCHES)








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Old Pinion Marking Specification
+4
New Pinion Marking
-4 ....................................... +0.008
-3 ....................................... +0.007
-2 ....................................... +0.006
-1 ....................................... +0.005
0 ........................................ +0.004
+1 ....................................... +0.003
+2 ....................................... +0.002
+3 ....................................... +0.001
+4 ............................................ 0

2) On models with 2-piece shafts, rotate transmission yoke
until trunnion is in horizontal plane. Install front drive shaft with
"U" joint trunnion in vertical plane. Connect bearing support to
crossmember.
3) Ensure that front face of bearing support is perpendicular
(90 degrees) to centerline of drive shaft. Install rear drive shaft
with "U" joint trunnion of slip joint in vertical plane.
4) Set differential pinion yoke trunnion in vertical plane.
Connect rear drive shaft to pinion yoke. If 2-piece shaft is correctly
installed, centerline of trunnions at each end of individual shafts
will be parallel. See Fig. 3.
Fig. 3: Phase Alignment Of 2-Piece Drive Shafts
Trunnion yoke ears on each shaft must be parallel.
DRIVE SHAFT BALANCE TEST
1) Drive shaft imbalance may often be cured by disconnecting
shaft and rotating it 180 degrees in relation to other components.
Test by raising rear wheels off ground, and turning shaft with engine.
NOTE: DO NOT run engine without ram airflow across radiator for
prolonged periods, as overheating of engine or transmission
may occur.
2) On most models, balance testing may be done by marking
shaft in 4 positions, 90 degrees apart. Place marks approximately 6"
forward of weld, at rear end of shaft. Number marks one through 4.
3) Place screw-type hose clamp so clamp head is in number one
position, and rotate shaft with engine. If there is little or no
change, move clamp head to No. 2 position, and repeat test.
4) Continue procedure until vibration is at lowest level. If
no difference is noted with clamp head moved to all 4 positions,
vibrations may not be drive shaft imbalance.
5) If vibration is lessened but not completely gone, place 2
clamps at that point, and run test again. Combined weight of clamps in
one position may increase vibration. If so, rotate clamps 1/2" apart,
above and below best position, and repeat test.
6) Continue to rotate clamps as necessary, until vibration is
at lowest point. If vibration level is still unacceptable, leave rear
clamp(s) in position and repeat procedure at front end of drive shaft.\
If vibration can be eliminated or reduced to acceptable levels using
this test procedure, send drive shaft out to be balanced.