JEEP CHEROKEE 1988 Service Repair Manual
Page 381 of 1378
discard. Tap ring gear loose with soft mallet. If ring gear runout
measured earlier exceeded .006" (.15 mm), repeat runout measurement of\
case without ring gear. Total runout of case should not exceed .003"
(.08 mm).
7) Using Flange Holder Wrench (C-3281), remove drive pinion
nut and washer. Using holder wrench and Flange Puller (C-452), remove
drive pinion flange. Using Pinion Seal Puller (C0748), remove pinion
oil seal. Remove slinger, gasket, outer pinion bearing and preload
shim pack.
8) Remove drive pinion with inner bearing. Remove inner and
outer pinion bearing races. Remove and note thickness of shim pack
behind inner bearing race. Remove inner pinion bearing from pinion
shaft using Puller Press (DD-914-P) with Adapter Ring (DD-914-9) and\
Pinion Bearing Puller Plates (C-293-39 on Model 44; DD-914-37 on Model
60 and 61; DD-914-95 on Models 70 and 80).
NOTE: Pinion bearing adjusting shims may remain on pinion shaft,
stick to bearing or fall loose. Collect and save them for
reassembly.
9) Remove side bearings with Bearing Puller (C-293-PA),
Extension Plug (C-293-3 on Model 44; DD-914-7 on Models 60, 61, 70 and
80) and Puller Plates (C-293-18 on Model 44; DD-914-62 on Models 60,
61, 70 and 80). Record shim thickness and location for reassembly
reference.
10) If differential case is a one-piece unit, drive out lock
pin holding differential pinion shaft to case. Remove differential
pinion shaft, gears and thrust washers (one for each gear).
11) If differential case is a 2-piece unit, mark both
differential case halves to aid reassembly in correct position. Remove
bolts holding case halves together. Tap on top half of case to break
it loose from lower half. Remove top half of case. Remove pinion gear
spider, pinion gears, side gears and all thrust washers.
INSPECTION
1) Use cleaning solvent to rinse gears and bearings. Check
large end of bearing rollers where wear, if any, is evident. Check
pinion and flange splines for excessive wear. Ensure ring gear teeth
are in good condition.
2) Check differential case for cracks, scoring of side gears,
thrust washers and pinion thrust faces. Check fit of side gears to
case and to axle shaft splines. Look at pinion shaft and spacer for
scoring or excessive wear.
REASSEMBLY & ADJUSTMENTS
1) When reassembling and adjusting ring and pinion assembly,
pinion depth, pinion bearing preload, side bearing preload and
backlash between ring and pinion must be adjusted.
2) If only pinion shaft and ring gear are to be replaced and
carrier housing can be reused, compare pinion depth adjustment numbers
etched in faces of old and new pinion heads. See Fig. 10. Using
PINION DEPTH SHIM ADJUSTMENT SPECS table, correct shims can be
selected for new pinion shaft depth adjustment.
Page 382 of 1378
Fig. 10: Location of Pinion Gear Markings W/ Depth Adjustment Figures
NOTE: In order to use PINION DEPTH SHIM ADJUSTMENT SPECS table,
old pinion shaft shim pack dimensions MUST be determined
accurately. If original pinion shaft shim pack dimension
cannot be determined accurately, Pinion Depth Gauge Set
(D-271) must be used to properly determine pinion depth
setting. Depth gauge set must also be used if new carrier
housing is to be used.
PINION DEPTH SHIM ADJUSTMENT SPECS
PINION DEPTH SHIM ADJUSTMENT CHART (INCHES) \
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Old New Pinion Marking
Pinion
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Marking -4 -3 -2 -1 0 +1 +2 +3 +4 \
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+4 +0.008+0.007+0.006+0.005+0.004+0.003+0.002+0.001 0 \
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+3 +0.007+0.006+0.005+0.004+0.003+0.002+0.001 0 -0.001 \
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+2 +0.006+0.005+0.004+0.003+0.002+0.001 0 -0.001-0.002 \
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+1 +0.005+0.004+0.003+0.002+0.001 0 -0.001-0.002-0.003 \
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0 +0.004+0.003+0.002+0.001 0 -0.001-0.002-0.003-0.004 \
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-1 +0.003+0.002+0.001 0 -0.001-0.002-0.003-0.004-0.005 \
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-2 +0.002+0.001 0 -0.001-0.002-0.003-0.004-0.005-0.006 \
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-3 +0.001 0 -0.001-0.002-0.003-0.004-0.005-0.006-0.007 \
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-4 0 -0.001-0.002-0.003-0.004-0.005-0.006-0.007-0.008 \
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PINION DEPTH SHIM ADJUSTMENT CHART (MILLIMETERS)
Page 383 of 1378
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Old New Pinion Marking
Pinion
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Marking -10 -8 -5 -3 0 +3 +5 +8 +10 \
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+10 +0.20 +0.18 +0.15 +0.13 +0.10 +0.08 +0.05 +0.03 0 \
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+8 +0.18 +0.15 +0.13 +0.10 +0.08 +0.05 +0.03 0 -0.03 \
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+5 +0.15 +0.13 +0.10 +0.08 +0.05 +0.03 0 -0.03 -0.05 \
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+3 +0.13 +0.10 +0.08 +0.05 +0.03 0 -0.03 -0.05 -0.08 \
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0 +0.10 +0.08 +0.05 +0.03 0 -0.03 -0.05 -0.08 -0.10 \
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-3 +0.08 +0.05 +0.03 0 -0.03 -0.05 -0.08 -0.10 -0.13 \
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-5 +0.05 +0.03 0 -0.03 -0.05 -0.08 -0.10 -0.13 -0.15 \
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-8 +0.03 0 -0.03 -0.05 -0.08 -0.10 -0.13 -0.15 -0.18 \
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-10 0 -0.03 -0.05 -0.08 -0.10 -0.13 -0.15 -0.18 -0.20 \
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3) The pinion depth adjustment number is determined by
manufacturer at time of assembly. Number represents distance best
running position of pinion shaft deviates from "nominal" or standard
distance between pinion gear face and center line of axle. See
Fig. 11 .
Fig. 11: Pinion Setting Standard Dimension
NOTE: Dimensions for Models 44, 61 and 80 not available.
NOTE: These are "nominal" distances from center of ring gear to
Page 384 of 1378
face of pinion shaft. Deviations are noted on pinion face.
4) Pinion Depth Gauge Set (D-271) allows shim pack
adjustments to be made without having to remove and replace
differential bearings. See Fig. 12.
Fig. 12: Pinion Depth Gauge Set (D-271)
NOTE: This set can be used on Models 44, 60, 61, 70 and 80.
5) Place differential case in holding fixture or vise.
Page 385 of 1378
Lubricate all parts with gear oil. On one-piece case, place side gears
and new thrust washers in case. Place differential pinions and new
thrust washers in case. Rotate side gears until holes in pinion gears
and washers line up with holes in case. Install differential pinion
shaft. Install lock pin after aligning hole in shaft with hole in
case. Peen edge of hole to keep pin in place.
6) On 2-piece case, Install side gears and new washers with
pinion gears and cross shaft into half of case that is flanged. Put
top half of case on bottom half. Align scribe marks made before
disassembly. Tighten all bolts finger tight. Tighten bolts alternately
to 65-70 ft. lbs. (88-95 N.m).
7) On all one and 2-piece case units, inspect ring gear and
case for any burrs or nicks. Install ring gear and tighten NEW ring
gear bolts evenly in alternating pattern to specification.
8) Install Master Bearings into case. Use (D-135) for Model
44 or (D-117) for Models 60, 61, 70 and 80. Install differential case
in carrier. Install and tighten side bearing caps finger tight over
master bearings. Caps must be in same location as marked during
disassembly. Mount dial indicator on carrier with indicator tip
against back of ring gear.
9) Pry case assembly to one side of carrier. Zero dial
indicator and pry case in opposite direction. See Fig. 13. Record
reading. This indicates thickness of shim pack necessary to eliminate
clearance between case and side bearing races.
10) Actual placement of shim pack and necessary preload will
be calculated after drive pinion is installed and pinion depth has
been determined. Remove dial indicator. Remove bearing caps and
differential case from carrier.
NOTE: If new differential side and pinion gears are used with new
washers, gear backlash should be correct due to close
machine tolerances. If old gears and/or washers are used,
gear backlash must be checked.
Fig. 13: Measuring Differential Case End Play
NOTE: If original ring and pinion is to be used, measure old shim
packs and make up packs of same dimensions with new shims.
Baffles are considered part of shim pack.
Page 386 of 1378
PINION DEPTH
1) Depth Gauge Set (D-271) is used to determine pinion depth\
.
Place Master Pinion Block (D-139 on Model 44; D-120 on Model 60 and
61; D-137 on Model 70; T80T-4020-F42 on Model 80) in pinion bore of
carrier. Put Arbor Discs (D-115-4-44 on Model 44; D-116-2 on Models
60,61 and 70; (T88T-4020-A) on Arbor (D-115-3). Install arbor in
carrier with discs riding in bearing bore.
2) Put Pinion Height Block (D-115-1-44 on Model 44; D-116-1
on Models 60, 61, 70 and 80) on top of master pinion block with side
against arbor. Place Scooter Block (115-2) with Dial Indicator (D-106\
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5) on small step of pinion height block. Zero dial indicator with
scooter block flat on pinion height block.
3) Move scooter block so dial indicator tip touches arbor.
Move block back and forth (perpendicular to arbor) to get highest
reading. This reading, plus or minus value etched on pinion head, is
thickness of shim pack necessary for pinion bearing.
4) On Model 80, Use Gauge Tube (D81T-4020-F51) and Gauge
Block (D81T-4020-F56) to determine required thickness of shim pack.
5) On all models, measure shims separately with micrometer.
If baffle is used, its thickness must be included in shim pack. This
is also true if slinger is used between inner bearing and head of
pinion shaft. Place pinion height shim pack in carrier bore for inner
bearing race. Drive bearing race into carrier, making sure cup is
fully seated.
PINION BEARING PRELOAD
1) Drive outer pinion bearing into carrier housing. Press
inner pinion bearing onto pinion shaft using Press Tube (C-3095-A).
Ensure bearing seats fully. Insert pinion shaft into carrier. Install
outer bearing, slinger (if equipped), flange, washer and nut.
NOTE: Pinion preload shims and oil seal should NOT be installed at
this time.
2) Using an INCH lb. torque wrench, tighten pinion nut until
10 INCH lbs. (1.13 N.m) rotational torque is required to move pinion
shaft. Recheck pinion depth with arbor and discs at this time. Place
pinion height block on face of pinion shaft.
3) Place dial indicator on small step of height block for
Model 44, 60 and 61 axles. Place dial indicator on high step of block
for Models 70 and 80 axles. Zero dial indicator and move it across
arbor to get highest reading. If reading is within .002" (.05 mm) of
etching on pinion face, pinion depth is correct.
NOTE: If pinion depth is not with .002" (.05 mm) of etched number
on face of pinion, shim pack under inner bearing race must
be changed before proceeding with differential settings.
4) Remove pinion nut, washer, flange, slinger and outer
bearing. Place preload shims (removed during disassembly) on pinion.
Install bearing and slinger. After lightly coating lips with gear oil,
install pinion seal in carrier housing. Install flange, washer and NEW
pinion nut. Tighten nut to specification. See TORQUE SPECIFICATIONS
table at end of this article.
5) Using an INCH lb. torque wrench, measure preload
(rotational torque) of pinion shaft. Rotational torque required to
keep pinion shaft turning freely and smoothly should be 20-40 INCH
lbs. (2.3-4.5 N.m). If preload needs to be increased, remove a few
shims and recheck. To decrease preload, add a few shims and recheck.
See Fig. 14 .
Page 387 of 1378
Fig. 14: Carrier Housing Shim Positioning
DIFFERENTIAL BEARING PRELOAD
1) Install differential case in housing with master bearings
Page 388 of 1378
on case. Set up dial indicator in same position as when case end play
was checked. See Fig. 13. Press ring gear toward pinion head while
rocking ring gear so teeth mesh fully. Zero dial indicator while
holding ring gear into pinion gear.
2) Press differential case (ring gear) away from pinion gear\
.
Repeat until dial indicator gives same reading each time. This figure
is shim pack thickness necessary between case and side bearing on ring
gear side. Remove dial indicator and differential from carrier. Remove
master bearings from case.
3) Put calculated shim pack on hub of case at ring gear side.
Place side bearing on hub. Use Bearing Installer (C-4025A) and Handle
(C-4171) to drive bearing onto case until it is seated. Take remaining\
shim pack as determined from case end play measurement and install
pack on opposite side of case from ring gear.
4) Add .015" (.38 mm) thickness to shim pack opposite ring
gear to provide side bearing preload. Drive side bearing onto case
with installer and handle. Install spreader and dial indicator on
carrier housing. Spread housing .015" (.38 mm). Put side bearing races\
onto side bearings. Install differential case into carrier.
RING & PINION BACKLASH
1) Install side bearing caps, making sure reference marks
made on caps and carrier match. Tighten cap bolts to 80 ft. lbs. (108
N.m). Check backlash between ring and pinion gears at 3 points spaced
equal distance on ring gear. See Fig. 15.
Fig. 15: Measuring Backlash Between Ring & Pinion Gears
2) Backlash reading between ring and pinion gears should be
.004-.009" (.10-.23 mm). Maximum variation between readings at 3
points is .002" (.05 mm). If backlash is too high, move ring gear
Page 389 of 1378
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)
Page 390 of 1378
Drive Shaft Bolt ............................. 16 (22)
Spindle Attaching Nut ........................ 65 (88)
Tie Rod Nut .................................. 60 (80)
Wheel Lug Nut ............................... 80 (108)
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