1991 MITSUBISHI MONTERO differential

must be installed in original location.
2) Using bearing puller, remove differential case side
bearings. Loosen ring gear retaining bolts in diagonal sequence.
Remove ring gear.
3) Remove drive pinion shaft lock pin from ring gear side.
Remove pinion shaft and pinion gears. Remove side gears and thrust
spacers.
DRIVE PINION
1) Remove pinion flange nut. Scribe alignment mark on pinion
flange and pinion. Remove flange. Using soft-faced hammer, drive out
pinion. Remove rear bearing and oil seal from carrier. Remove rear
adjusting shim from pinion.
2) Press front bearing from pinion. Remove front adjusting
shim and spacer from pinion. Inspect all components for unusual wear
or damage. Replace as necessary.
DIFFERENTIAL REASSEMBLY & ADJUSTMENTS
CASE REASSEMBLY
1) Place side gear thrust spacers behind side gears in
original position. Assemble side gears in differential case. Install
pinion gears and washers. Rotate pinion gears to mesh with side gears.
2) Install pinion shaft without lock pin. Check pinion and
side gear backlash. Install wooden wedge to lock side gears. Using
dial indicator, measure gear backlash. See Fig. 3.
3) Backlash must be within specification. See PINION & SIDE
GEAR BACKLASH SPECIFICATIONS table. Adjust backlash by using different
side gear spacers. Ensure both sides are equally shimmed.
4) Install pinion shaft lock pin. Securely stake in 2 places.
Ensure adhesive is removed from ring gear mounting bolts and gear
mounting surface. Clean internal threads with tap.
5) Install ring gear on differential case. Ensure alignment
marks on differential case and ring gear are aligned. Apply Loctite
271 to bolts and install. Tighten bolts alternately in diagonal
sequence to specification. See TORQUE SPECIFICATIONS table at the end
of this article.
PINION & SIDE GEAR BACKLASH SPECIFICATIONS









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Application In. (mm)
Standard ....................... .003 (.08)
Wear Limit ..................... .008 (.20)









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1) Install drive pinion in differential carrier. Install
spacer, pinion front shim(s) and front pinion bearing. DO NOT install
oil seal at this time. Install pinion flange, washer and retaining
nut. Check pinion rotating torque without pinion oil seal.
2) Recheck rotating torque. Rotating torque must be within
specification. See PINION ROTATING TORQUE SPECIFICATIONS table. Adjust
rotating torque by replacing drive pinion front shims or spacer. Once
correct rotating torque is obtained, install oil seal. Coat seal lip
with grease.
3) Install pinion flange so alignment marks are correct.
Apply light coat of grease to flange washer contact area. Install new
retaining nut. Check pinion rotating torque with pinion oil seal
installed. Rotating torque must be within specification. See PINION
ROTATING TORQUE SPECIFICATIONS table.
SIDE BEARING
1) Using Bearing Installer (MB990802-01), install bearings o\
n
differential case. Select 2 side bearing adjusting shims thinner than
those removed. Shims must be equal thickness on both sides. Install
shims on each side of case assembly. Install case assembly in
differential carrier.
2) Push case assembly fully to one side of carrier. Using 2
feeler gauges, measure clearance between carrier and side bearing shim
at opposite sides of bearing. Remove shims from one side of
differential carrier.
3) Measure thickness of shims removed. Add removed shim
thickness and 1/2 of feeler gauge clearance measurement plus .002" (.
05 mm). This is thickness of shim that should be installed on each
side of case. Select proper shims. Install equal shims on each side of
case assembly.
NOTE: Ensure no clearance exists between gear carrier and
adjusting shim.
4) Install side bearing shims and differential case assembly
in differential carrier. Using brass drift, tap shims to fit them to
side bearing outer race. Install bearing caps. Check ring gear
backlash.
RING GEAR BACKLASH
1) Lock drive pinion in place. Using dial indicator, check
ring gear backlash at heel of ring gear tooth. Measure at 4 locations
of ring gear. Gear backlash must be within .004-.006" (.10-.15 mm).
2) If not within specification, change side bearing adjusting
shims and recheck backlash. If backlash is too small, install thinner
shim behind ring gear and thicker shim opposite ring gear.
3) If backlash is excessive, install thicker shim behind ring
gear and thinner shim opposite ring gear. Check gear tooth contact
using paint impression method.
CAUTION: When changing shims, total thickness of all shims must
remain constant.
RING GEAR RUNOUT
Using dial indicator, measure runout at back side of ring
gear. Runout must be within .002" (.05 mm). If runout is excessive,
change ring gear-to-differential case mounting position. Recheck
runout. Install cover and gasket.

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DRIV E A XLE - R EA R N O N-IN TE G RAL
1991 M it s u bis h i M onte ro
199192 DRIVE AXLES
Differentials & Axle Shafts - Rear Non-Integral
Mitsubishi: Montero, Pickup
DESCRIPTION
Rear axle features a rigid banjo-type housing with semi-
floating axle shafts. Differential consists of hypoid reduction gears
and straight bevel differential gears. Limited Slip Differential (LSD)\
is available on all models.
AXLE RATIO & IDENTIFICATION
Ratio is determined by dividing number of ring gear teeth by
number of drive pinion teeth.
AXLE RATIO SPECIFICATIONS









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Application Ratio
Montero .................................................. 4.63
Pickup
2WD w/Light Suspension ................................. 3.91
2WD w/Heavy Suspension ................................. 4.22
4WD .................................................... 4.22









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LUBRICATION
CAPACITY
REAR AXLE GEAR OIL CAPACITY








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Application Pts. (L)
Montero .................................. 5.4 (2.5)
Pickup
Conventional
2WD ................................... 3.2 (1.5)
4WD ................................... 5.5 (2.6)
LSD .................................... 5.5 (2.6)









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FLUID TYPE
Conventional differentials use API classification GL-5 SAE
80W or 90W. Limited slip differentials use Mitsubishi Gear Oil
(8149630 EX) or Mopar Gear Oil (4318058) and Mopar Friction Modifier\
(4318060).
TROUBLE SHOOTING
DRIVE AXLE (RWD) TROUBLE SHOOTING








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PROBLEM
Possible Cause Action

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KNOCKING OR CLUNKING
Differential Side Gear Clearance .............. Check Clearance
Worn Pinion Shaft ........................ Replace Pinion Shaft
Axle Shaft End Play ............................ Check End Play
Missing Gear Teeth ................... Check Diff./Replace Gear
Wrong Axle Backlash ............................ Check Backlash
Misaligned Driveline ........................ Realign Driveline
CLUNKING DURING ENGAGEMENT
Side Gear Clearance ................. Check Side Gear Clearance
Ring and Pinion Backlash ....................... Check Backlash
Worn/Loose Pinion Shaft ................. Replace Shaft/Bearing
Bad "U" Joint ............................... Replace "U" Joint
Sticking Slip Yoke ............................. Lube Slip Yoke
Broken Rear Axle Mount .......................... Replace Mount
Loose Drive Shaft Flange ......................... Check Flange
CLICK/CHATTER ON TURNS
Differential Side Gear Clearance .............. Check Clearance
Worn Clutch Plates (1) .................. Replace Clutch Plates
Wrong Diff. Lubricant (1) .................... Change Lubricant
RHYTHMIC KNOCK OR CLICK
Flat Spot on Rear Wheel Bearing ......... Replace Wheel Bearing
HUM/LOW VIBRATION AT ALL SPEEDS
Faulty Wheel Bearings ........................ Replace Bearings
Faulty "U" Joint ............................ Replace "U" Joint
Faulty Drive Shaft ........................ Balance Drive Shaft
Faulty Companion Flange ........................ Replace Flange
Faulty Slip Yoke Flange ........................ Replace Flange
(1) - Limited slip differential only.









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DRIVE AXLE (FWD)
DRIVE AXLE (FWD) TROUBLE SHOOTING








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PROBLEM
Possible Cause Action









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GREASE LEAKING
Ripped CV Boot ................................... Replace Boot
CLICKING NOISE WHILE CORNERING
Dry/Worn CV Joints .................... Replace Outer CV Joints
CLUNK ON ACCELERATION
Dry/Worn CV Joints .................... Replace Inner CV Joints
Worn Trans. Gears/Bearings ..................... Inspect Trans.
VIBRATION/SHUDDER ON ACCELERATION
Dry/Worn CV Joints .......................... Replace CV Joints
Alignment Out ................................. Check Alignment
Incorrect Spring Height ................... Check Spring Height
SQUEALING OR HUMMING
Dry/Worn CV Joints ..................... Lube/Replace CV Joints
Faulty Wheel Bearing .................... Replace Wheel Bearing









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TESTING & INSPECTION
AXLE SHAFT END PLAY
Using dial indicator, check axle shaft end play. End play
must be .0020-.0079" (.05-.20 mm). If end play is not within
specification, change shims to obtain correct end play. See AXLE
SHAFTS under REMOVAL & INSTALLATION.
AXLE TOTAL BACKLASH
1) Raise and support rear axle. Place transmission in
Neutral. Apply parking brake. Rotate drive shaft clockwise. Place
reference marks on pinion dust cover and differential housing.
2) Rotate drive shaft counterclockwise and measure distance
between reference marks. Differential must be removed and backlash
adjusted if distance exceeds 0.2" (5.0 mm).
LIMITED SLIP DIFFERENTIAL PRELOAD
1) Place transmission in Neutral. Block front wheels. Raise
one rear wheel free of ground and remove wheel. Use Axle Puller
Adapter (MB990241) for Montero and Pickup models. Install adapter on
wheel studs. Release parking brake.
2) Using torque wrench, measure starting torque on Pickup
models while rotating wheel in forward direction. On Montero models,
measure rotating torque. This measurement is read once axle is
turning. Differential must be repaired if torque is less than
specification. See TESTING SPECIFICATIONS table.

thickness into left side axle housing. Install left axle shaft
assembly into axle housing and tighten nuts to specification. See
TORQUE SPECIFICATIONS table at the end of this article.
2) Install right axle shaft assembly into axle housing
WITHOUT a shim or "O" ring. Temporarily tighten nuts in diagonal
sequence to 51.6 INCH lbs. (5.8 N.m) in 2 stages. Measure clearance
between bearing case and rear axle housing end with a feeler gauge.
3) Select shims equal to the sum of the thickness of the
measured clearance plus .0020-.0079" (.05-.20 mm). Remove right axle
shaft and install the selected shim(s) and "O" ring into right axle
housing end. Install right axle shaft assembly into rear axle housing.
Tighten nuts in diagonal sequence to specification. See TORQUE
SPECIFICATIONS table.
4) Using dial indicator, check end play of axle shaft. End
play must be .0020-.0079" (.05-.20 mm). If end play is not within
specification, change shim(s) to obtain correct end play. Reverse
removal procedure to install remaining components. Adjust parking
brake and bleed brake system.
DIFFERENTIAL CARRIER
Removal
Raise and support vehicle. Drain gear oil. Mark drive shaft
flange-to-pinion flange position. Remove drive shaft. Remove axle
shafts. See AXLE SHAFTS under REMOVAL & INSTALLATION. Support
differential carrier with jack. Remove differential carrier retaining
nuts. Remove differential carrier.
Inspection
Inspect for leakage at vent plug, differential carrier
companion flange and where carrier joins axle housing.
Installation
Apply sealant to axle housing surface. To install, reverse
removal procedure. Align marks on drive shaft and pinion flange.
DRIVE SHAFT
Removal
Make match marks on drive shaft yoke flange and pinion
flange. Remove bolts. Remove drive shaft from vehicle.
Installation
To install, reverse removal procedure. Ensure match marks are
aligned. Tighten bolts to specification. See TORQUE SPECIFICATIONS
table at end of article.
OVERHAUL
AXLE SHAFTS
Disassembly
1) Mount backing plate and axle shaft assembly in soft-jawed
vise. Bend over axle shaft bearing lock washer. Using Spanner Wrench
(MD990785), remove lock nut from axle shaft. Remove washers. Reinstall\
lock nut on axle shaft approximately 3 turns.
2) Attach Bearing Puller (MB990787-01) to rear of backing
plate to remove bearing case from axle shaft. See Fig. 2. Using equal
pressure to avoid binding, tighten puller nuts diagonally to remove
bearing case. Using hammer and drift, remove bearing outer race from
bearing case. Remove oil seal from end of axle housing with Slide
Hammer and Adapter (MB990211).

Fig. 2: Removing Bearing Case from Axle Shaft
Courtesy of Chrysler Motors.
Inspection
Inspect bearings for roughness, pitting or damage. Inspect
axle shaft for damaged splines or flange. Inspect bearing case for
cracks or damage. Measure axle shaft O.D. in bearing area. Correct O.
D. is 1.57" (39.8 mm). Axle shaft must be replaced if O.D. is not to
specification.
Reassembly
1) Apply grease to outer surface of bearing outer race and
oil seal.Install outer race in bearing case. Install oil seal in
bearing case until it is even with bearing case surface. Apply grease
to bearing rollers. Install brake assembly, bearing case and bearing
onto axle shaft.
2) Apply grease to bearing rollers. Press inner bearing onto
axle shaft. Pack bearing case with grease. Coat lock nut threads with
grease. Install washer, NEW lock washer and lock nut. Lock nut must be
installed with chamfered edge toward axle shaft flange. Tighten lock
nut to specification. See TORQUE SPECIFICATIONS table at end of
article. Bend tab on lock washer into groove on lock nut.
DIFFERENTIAL
NOTE: Check pinion and side gear backlash, ring gear backlash and
ring gear runout before disassembly.
Disassembly
1) Remove differential carrier from axle housing. Remove lock

plates and side bearing nuts. See Fig. 3. Mark bearing caps for
location. Remove bearing caps. Remove differential case assembly from
differential carrier.
CAUTION: Ensure side bearing nuts, bearing caps and side bearings
are marked for location. Components must be installed in
original location.
Fig. 3: Exploded View of Conventional Rear Differential
Courtesy of Chrysler Motors.
2) Using bearing puller, remove differential case side
bearings. Place alignment marks on ring gear and differential case for
reassembly. Loosen ring gear bolts in diagonal sequence. Remove ring
gear.
3) On conventional axles, remove drive pinion shaft lock pin
from differential case. Remove differential pinion shaft and thrust
block (if equipped). Remove pinion gears and washers. Remove side
gears and thrust spacers. Mark components for reassembly reference.
4) On limited slip units, mark differential case and
differential case cover for reassembly reference. Remove differential
case retaining screws. Separate differential case and cover. Remove
components from case. See Fig. 4. Mark components for location.