ISUZU AXIOM 2002 Service Repair Manual

4A2±22DIFFERNTIAL (REAR)
425RW018Preload should be at 1.0 to 1.6 N´m (8 to 14 in lbs.)
on new bearings, or 0.46 to 0.69 N´m (4 to 6 in lbs.)
for used bearings.

If the preload torque is below the preloads given
above, continue torquing the nut in small
increments. Check the preload after each
tightening. Each tightening increases the bearing
preload by several pounds. If the bearing preload is
exceeded, the pinion will have to be removed, and a
new collapsible spacer installed.

Once a preload of 1.0 to 1.4 N´m (8 to 12 in lbs.)
has been obtained, rotate the pinion several times
to assure that the bearings have seated. Recheck
the preload, and adjust if necessary.
Determination of Backlash & Preload
Shims
1. Install master side bearings onto the case.
2. Install differential assembly into the carrier.
3. Install the bearing cap and finger tight bolts.
4. Set up the dial indicator.
5. Force the differential assembly away from the pinion
gear until it is completely seated against the cross
bore face of the carrier.
6. With force still applied to the differential case, place
the tip of dial indicator on a machined surface of the
differential case, if available, or on the head of a ring
gear screw, and set the indicator at zero(0).
7. Force the ring gear to mesh with the pinion gear. Rock
the ring gear slightly to make sure the gear teeth are
meshed. Repeat this procedure several times until
the same reading is obtained each time. Be sure the
indicator reads zero(0) each time the ring gear is
forced back into contact with the cross bore face. This
reading will be the necessary amount of shims to be
placed between the differential case and side bearing
cone on the ring gear side.8. The remaining amount of shims, which is the
difference between the overall found in step 6 of Side
Bearing Pre-load Adjustment and step(7) above,
should be placed on the other side of the differential
case, plus additional 0.38 mm (0.015 in) for obtaining
preload and backlash.
9. Place the required amount of shims on each hub as
determined in the previous steps and assemble side
bearing cone by using installer J±21784 and handle
J±8592.
425RW022
10. Total torque to rotate Ð Increase of pinion torque to
rotate due to differential case assembly shall not
exceed 3.4 N´m (30 in lbs.) divided by the gear ratio.
11. Assembly the spreader J±24385±B and indicator to
the carrier as shown in figure. Spread the carrier
0.5 mm (0.02 in) for differential installation.
420RW004
CAUTION: Do not spread the carrier over 0.5 mm
(0.02 in).
12. Remove the indicator.

DIFFERENTIAL (REAR)4A2±23
Backlash Adjustment
1. Install the differential case assembly and bearing
caps.
2. Rotate the case several times to seat the bearings.
3. Remove the spreader.
4. Install the side bearing cap bolts.
Tighten side bearing cap bolts
Torque: 108 N´m (80 lb ft)
5. Install a dial indicator to the case using a magnetic
base.
6. Place the indicator stem at the heel end of a tooth.

Set the dial indicator so that the stem is in line with
the gear rotation and perpendicular to the tooth
angle.
425RS087
7. Check and record the backlash at three points around
the ring gear.

The pinion must be held stationary when checking
backlash.

The backlash should be the same at each point
within 0.07 mm (0.003 in). If the backlash varies
more than 0.07 mm (0.003 in), check for burrs, a
distorted case flange, or uneven bolting conditions.
8. Backlash at the minimum lash point measured should
be between 0.13 and 0.20 mm (0.005 and 0.008 in)
for all new gear sets.
9. If the backlash is not within specifications, move the
ring gear in or out from the pinion by increasing the
thickness of one shims, and decreasing the thickness
of the other shim by the same amount.
This will maintain the correct rear axls side bearing
preload.

Moving 0.05 mm (0.002 in) worth of shim from one
side of the differential to the other will change the
backlash adjustment by 0.03 mm (0.001 in).
10. After obtaining correct tooth contact described in
later, install ABS speed sensor.11. Install the cover with sealant.
Torque: 40 N´m (30 lb ft)
12. Fill the axle lubricant.
Gear Tooth Pattern Check
Checking the ring gear to pinion tooth pattern is to be
done only after setting up the axle according to the
methods in this section. The pattern check is NEVER to
be used as an initial check, or instead of checking pinion
depth and backlash adjustments.
This check is only to be verify the correct adjustment of
the gear set after set up.
425RS038
Legend
(1) Heel
(2) Toe
(3) Concave Side (Coast)
(4) Convex Side (Drive)
1. Wipe all oil out of the carrier, and carefully clean each
tooth of the ring gear.
2. Use gear marking compound 1052351 or equivalent
and apply this mixture sparingly to all ring gear teeth,
using a medium-stiff brush. When properly used, the
area of pinion tooth contact will be visible when hand
load is applied.
3. Tighten the bearing cap bolts to the specified torque.
4. Expand the brake shoes until a torque of 54 to 68 N´m
(40 to 50 lb ft.) is required to turn the pinion. A test
made without loading the gears will not give a
satisfactory pattern. Turn the pinion flange with a
wrench so that the ring gear rotates one full
revolution, then reverse the rotation so that the ring
gear rotates one revolution in the opposite direction.
5. Observe the pattern on the ring gear teeth and
compare this with figure.

4A2±24DIFFERNTIAL (REAR)
425RS039
Adjustments Affecting Tooth Contact
Two adjustments can be made which will affect tooth
contact pattern: backlash, and the position of the drive
pinion in the case. The effects of bearing preloads are not
readily apparent on head loaded tooth contact pattern
tests; however, these adjustments should be within
specifications before proceeding with backlash and drive
pinion adjustments.
The position of the drive pinion is adjusted by increasing
or decreasing the distance between the pinion head and
the centerline of the ring gear.
Decreasing the distance will move the pinion closer to the
centerline of the ring gear. Increasing the distance will
move the pinion farther away from the centerline of the
ring gear.
Backlash is adjusted by means of the side bearing
adjusting shims which move the entire case and ring gear
assembly closer to, or farther from, the drive pinion. (The
adjusting shims are also used to set side bearing
preload.)
If the thickness of the right shim is increased (along with
decreasing the left shim thickness), backlash will
increase.
The backlash will decrease if the left shim thickness is
increased (along with a decrease in right shim thickness).

DIFFERENTIAL (REAR)4A2±25
Differential Case Assembly
Disassembled View
425RW014
Legend
(1) Thrust Washer (for Pinion Gear)
(2) Pinion Mate Gear
(3) Thrust Washer(for Side Gear)
(4) Side Gear(5) Differential Shaft
(6) Lock Pin
(7) Bolt
(8) Differential Case

4A2±26DIFFERNTIAL (REAR)
Disassembly
1. Remove lock pin using a small drift.
425RS098
2. Remove the differential shaft by using a soft metal rod
and a hammer.
425RS043
3. Remove pinion mate gear and thrust washer.
4. Remove side gear and thrust washer.
Inspection and Repair
Make necessary correction or parts replacement if wear,
damage, corrosion or any other abnormal condition are
found through inspection.
Check the following parts.

Ring gear, pinion gear

Bearing

Side gear, pinion mate gear, differential shaft

Differential case, carrier

Thrust washer

Oil seal
Reassembly
1. Install side gear with thrust washer.
2. Install the pinion mate gear with thrust washer by
engaging it with the side gears while turning both
pinion mate gears simultaneously in the same
direction.
425RS048
3. Install differential shaft.
1. Be sure to install the differential shaft so that it is in
alignment with the lock pin hole in the differential
case.
425RS049
4. Install lock pin.
After lock pin installation, stake the case to secure the
lock pin.

DIFFERENTIAL (REAR)4A2±27
Limited Slip Differential Assembly
Disassembled View
425RW004
Legend
(1) Thrust Washer±Differential Pinion Mate Gear
(2) Pinion Mate Gear
(3) Dished Spacer
(4) Disc
(5) Plate(6) Differential Plate Retainer
(7) Lock Pin
(8) Differential Case
(9) Ring Gear Bolts
(10) Differential Shaft
(11) Differential Side Gear
Disassembly
1. Place the holder J±39824 into a vise.
Position the differential on the holder with the ring
gear side down.
2. Remove Lock pin (1) from differential shaft using a
punch.
3. Remove Differential shaft (2) using hammer and
punch.
Place shop towel behind case to prevent differential
shaft from dropping out of case.
425RW005

4A2±28DIFFERNTIAL (REAR)
4. Assemble clutch pack unloading tool .
a. Install cap J±34174±1 to the bottom differential
side gear.
b. Install threaded screw cap J±34174±2 to top
differential side gear. Thread forcing screws
J±22342±15 into threaded screw cap until it
becomes centered into the bottom cap.
901RW153
c. Tighten forcing screw until tight enough to collapse
dished spacers and allow looseness between side
and pinion mate gears.
5. Both pinion mate gear thrust washers using a shim
stock (1) of 0.51 mm (0.020 in.) or equivalent tool to
push out washers.
425RW007
6. Relieve tension of dished spacers by loosening
forcing screw.NOTE:

You may have to adjust the forcing screw slightly to
allow the case to rotate.
7. Assemble LSD service adapter J±39834 onto long
drive handle J±8592.Insert it into differential shaft
hole of case. Pull on handle and rotate case until
pinion mate gears can be removed.
901RW068
8. Remove pinion mate gears.
9. Hold side gear top clutch pack (1) with one hand and
remove positraction unloading tools.
425RW008
10. Remove top side gear and clutch pack.
NOTE:

Keep the stack of plates and discs intact and in
exactly the same position while they are being
removed.
11. Remove case from holder. Turn case with flange or
ring gear side up to allow side gear and clutch pack to
be removed from case.

DIFFERENTIAL (REAR)4A2±29
12. Remove differential plate retainer from both clutch
packs to allow separation of the plates and discs.
NOTE:

Keep the discs and plates in the same order as they
were removed.
425RW009
Legend
(1) Differential Plate
(2) Differential Disc
(3) Dished Spacer
(4) Side Gear
Inspection and Repair
Cleaning

All parts with solvent.
Visual Inspection

Clean all parts with solvent.

Plates and Discs. If any one disc or plate in either
stack shows evidence of excessive wear or scoring,
the complete stack is to be replaced on both sides.

Side Gears and Pinion Mate Gears. The gear teeth of
these parts should be checked for extreme wear and
possible cracks. The external teeth of the side gear,
which retain the concentric groove discs, should also
be checked for wear or cracks.

If replacement of one gear is required due to wear,
etc., then both side gears, pinion mate gears, and
thrust washers are to be replaced.

Differential Shaft. If excessive wear is evident, the
differential shaft should be replaced.

Differential Plate Retainers. If wear is evident on any
one of the differential plate retainers, all four retainers
must be replaced.

Differential Case. If scoring, wear or metal pickup is
evident on the machined surfaces, replacement of
the case is necessary.
Reassembly
1. Lubricate thrust face of side gears, plates and discs
with the proper limited slip rear axle lubricant.
2. Assemble plates and discs in exactly in the same
position as they were removed, regardless of whether
they are new or original.
3. Install differential plate retainer to ears of plates.
NOTE:

Make sure both retainers are Completely seated on
ears of plates.
4. Install clutch pack and side gear into bottom side gear
bore. Make sure clutch pack stays assembled to side
gear splines, and that retainers are completely seated
into pockets of case.
NOTE:

To prevent clutch pack from falling out of case, hold
clutch pack in place by hand while repositioning case
on bench.
5. Install other side gear and clutch pack. Make sure
clutch pack stays assembled to side gear splines, and
retainers are completely seated into pockets of case.
6. Hold clutch pack in position and assemble screw cap
J±34174±2, cap J±34174±1 and forcing screw
J±22342±15. Tighten forcing screw into bottom cap
to hold both clutch packs in position.
7. With tools assembled to case, position case on holder
J±39824 by aligning splines of side gear with those of
shaft. Tighten forcing screw to compress clutch packs
in order to provide clearance for pinion mate gears.
901RW069
8. Install pinion mate gears.

Place the pinion mate gears into the differential 180
degrees apart.

4A2±30DIFFERNTIAL (REAR)
9. While holding gears in place, insert LSD service
adapter J±39834 with long drive handle J±8592 in
differential shaft hole of case. Pull on long drive
handle J±8592 and rotate case, allowing gears to
turn. Make sure that holes in pinion mate gears align
with holes in case.
901RW070

It may be necessary to adjust tension on forcing
screw to rotate case.
10. Tighten forcing screw to compress the clutch packs,
to allow installation of spherical thrust washers.
11. Lubricate spherical thrust washers (2), and assemble
into case (1). Use a small screw driver to push
washers into place. Remove tools.
425RW012
12. Position differential shaft in case and drive in with
hammer. Be sure lock pin hole of differential shaft (5)
is properly aligned to allow installation of lock pin (3).
Be sure that thrust washers and differential pinion
mate gears are aligned with the differential case (4).
Install new lock pin to proper depth using a punch.
Stake metal of case over pin in two places, 180
degrees apart.
425RW013

DIFFERENTIAL (REAR)4A2±31
Main Data And Specifications
General Specifications
Rear axle
TypeSalisbury, Semi±floating
Rear axle Size226 mm (8.9 in)
Gear typeHypoid
Gear ratio4.300
Differential typeTwo pinion
Lubricant GradeGL±5: (Standard differential)
GL±5, LSD: (Limited slip differential)
Locking Differential Lubricant80W90 GL±5
(USE Limited Slip Differential Gear Lubricant or Friction
Modifier Organic Additive)
Capacity1.77 liter (1.87 US qt)
Torque Specifications
E04RX002