differential MITSUBISHI MONTERO 1991 User Guide

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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.

Fig. 4: Exploded View of Typical Limited Slip Differential
Courtesy of Chrysler Motors.
Drive Pinion
1) Remove pinion flange retaining nut. Scribe alignment marks
on drive pinion and pinion flange for reassembly. Using soft-faced
hammer, drive out pinion. Remove front adjusting shim and spacer from
pinion.
2) Using bearing puller, remove rear bearing from pinion.
Remove rear adjusting shim from pinion. Remove oil seal and bearing
races from differential carrier.
Inspection
1) Inspect all gears for cracked or flaking teeth. Inspect
pinion shaft for wear. Inspect pinion flange and drive pinion for
damaged splines.
2) Inspect bearings and races for roughness or flaking.
Replace worn components. On limited slip axles, inspect clutch
components and contact areas for wear or overheating. Inspect friction
plates, friction discs, spring plates and pressure rings for signs of
seizure, excessive heat, severe friction or nicks.
NOTE: Outer areas of friction surfaces will wear heavier due to
clutch plate and preload spring.
3) Using dial indicator, check friction plate and friction
disc for warpage. Replace components if beyond specification. See
FRICTION PLATE & DISC SPECIFICATIONS table.
4) Measure friction plates and disc thickness at projection
areas not within wear area. Measure plate and disc thickness in
friction surface. Difference between thickness of projections and
friction surface indicates amount of wear. Replace components if not

within specification. See FRICTION PLATE & DISC SPECIFICATIONS table.
FRICTION PLATE & DISC SPECIFICATIONS









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Application In. (mm)
Warpage Limit ......................... .003 (.08)
Wear Limit ............................ .004 (.10)









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DIFFERENTIAL OVERHAUL
CASE ASSEMBLY (CONVENTIONAL)
1) Install thrust spacers, side gears, pinion washers and
pinion gears in differential case. DO NOT install thrust block (if
equipped) at this time.
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. 5.
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.
PINION & SIDE GEAR BACKLASH SPECIFICATIONS









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Application In. (mm)
4-Cylinder Engine
Standard .................. .0004-.0030 (.010-.076)
Wear Limit ............................. .008 (.20)
V6 Engine
Standard ......................... 0-.0030 (0-.076)
Wear Limit ............................. .008 (.20)









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Fig. 5: Checking Pinion & Side Gear Backlash
Courtesy of Chrysler Motors.
4) Install thrust block (if equipped) once correct backlash
is obtained. Install pinion shaft lock pin from back side of ring

gear. Securely stake pin in 2 places. Ensure adhesive is removed from
ring gear mounting bolts and gear mounting surface. Clean internal
threads with tap.
5) Ensure alignment marks on differential case and ring gear
are aligned. Apply Loctite 271 to bolts and install ring gear on
differential case. Tighten bolts in diagonal sequence to
specification. See TORQUE SPECIFICATIONS table at the end of this
article.
CASE ASSEMBLY (LIMITED SLIP)
1) Assemble 2 friction discs and 2 friction plates; assemble
plate, disc, plate and disc. Measure assembly thickness. Assemble
discs and plates to give standard difference of .002" (.05 mm) between\
the 2 sides.
2) Assemble spring plates and spring discs with one on each
side. Measure assembly thickness. Assemble disc and plates to obtain
minimum difference in thickness between each assembly.
3) Assemble clutch assemblies, pressure rings, pinion gears,
side gears and pinion shaft. Measure overall width of assembly plus
spring plates and spring discs. This measurement is "C". See Fig. 6.
Fig. 6: Measuring Clutch Assembly Width
Courtesy of Chrysler Motors.
4) Determine depth "D" of differential case, using formula
"D"="E"+"F"-"G" or "D"="E"+"H"-"F"-"G" . See Fig. 7. Subtract
measurement "C" from measurement "D" to determine spring plate-to-case

clearance. Adjust spring disc thickness to obtain proper spring plate-
to-case clearance. Correct clearance is .0024-.0079" (.060-.200 mm).
Fig. 7: Measuring Limited Slip Case Depth (Montero 3.0L & Pickup)
Courtesy of Chrysler Motors.
CAUTION: DO NOT interchange clutch components for right and left
sides. Mark clutch components for location.
5) Remove spring plates, spring discs, friction plates and
friction disc from pressure rings. Mark components for location.
Install thrust washers on each end of pressure rings. See Fig. 8.
6) Measure distance from end of thrust washer to rear face of
pressure ring. Select proper thickness thrust washers to obtain a .
002" (.05 mm) or less difference between measurements.
7) Once correct thrust washers are determined, install thrust
washers on pressure rings. Squeeze pressure rings together and measure
width from end of thrust washer to remaining thrust washer. This is
dimension "H". See Fig. 8.
8) Determine distance between thrust washer surfaces when
differential case is assembled. This is dimension "I"
("I"="J"+"K"+"L"). See Fig. 8. Dimension "J" is the same as dimension
"D" in step 4).