2002 ISUZU AXIOM sensor

DIFFERENTIAL (REAR)4A2±7
Installation
1. Install brake pipe.
2. Connect Antilock brake system (ABS) speed sensor
and harness, refer to
4±Wheel Anti±Lock Brake
System (ABS) in Brake
section.
3. Install brake disc.
4. Install brake caliper. Refer to
Disk Brakes in Brake
section.
5. Install axle housing assembly.
6. Install coil spring and insulator.
7. Install the lower link fixing bolt and nut to the axle
housing. For the procedures in items 7±11, refer to
Suspension section.
8. Install the upper link bolt and nut to the axle housing.9. Install the lateral rod fixing nut and bolt to the frame
side.
10. Install the stabilizer linkage mounting nut and bolt to
the frame side.
11. Install the shock absorber.
12. Install brake tube flare nut, Refer to
Disk Brakes in
Brake
section.
13. Install ABS connector and bracket.
14. Connect breather hose.
15. Install parking brake cable, Refer to
Parking Brakes in
Brake
section.
16. Bleed brakes. Refer to
Hydraulic Brakes in Brake
section.
Axle Shaft, Oil Seal and Bearing
Axle Shaft and Associated Parts
Disc Brake Model
420RW008
Legend
(1) Axle Shaft
(2) Backing Plate
(3) Oil Seal
(4) Bearing
(5) Axle Housing
(6) Lock Washer
(7) Nut
Drum Brake Model
420RX001
Legend
(1) Axle Shaft
(2) Backing Plate
(3) Oil Seal
(4) Bearing
(5) Axle Housing
(6) Lock Washer
(7) Nut

DIFFERENTIAL (REAR)4A2±13
Differential Assembly
Disassembled View
420RW018
Legend
(1) ABS Speed Sensor
(2) Housing
(3) Outer Pinion Bearing (Cup and Cone)
(4) Outer Oil Slinger
(5) Oil Seal
(6) Companion Flange Assembly
(7) Pinion Nut Washer
(8) Pinion Nut
(9) Collapsible Spacer
(10) Baffle Plate
(11) Inner Pinion Bearing (Cup and Cone)
(12) Inner Oil Slinger
(13) Pinion gear adj. Shim-Selective (Position)
(14) Ring gear and Pinion Gear Assembly
(15) Exciter Ring
(16) Differential Case(17) Lock Pin
(18) Axle Vent
(19) Gasket
(20) Cover and Clip Assembly
(21) Fill Plug (with Magnet)
(22) Mounting Bracket
(23) Side Bearing Cap Bolt
(24) Side Bearing Cap
(25) Ring Gear Bolts
(26) Differential Adjustment Shims (Side Bearing
Preload and Ring Gear/Pinion Backlash)
(27) Side Bearing (Cup and Cone)
(28) Differential Shaft
(29) Differential Side Gears
(30) Side Gear Thrust Washer
(31) Pinion Mate Gears
(32) Thrustwasher-Differential Pinion Mate Gear

4A2±14DIFFERNTIAL (REAR)
Inspecting the Axle Before
Disassembly
1. Remove the axle cover from the rear axle and drain
the axle lubricant into a suitable container.
2. Check ring gear backlash. Refer to
Backlash
Adjustment
in this section. This information can be
used to determine the cause of the axle problem. It
will also help when setting up the shim packs for
locating and preloading the differential cage.
3. Check case for metal chips and shavings. Determine
where these chips and shavings come from, such as
a broken gear or bearing cage.

If possible, determine the cause of the axle problem
before disassembly.
Disassembly
1. Remove axle shafts.

Refer to
axle shaft replacement in this section.
2. Remove ABS sensor.
3. Remove bearing caps and bolts.

Mark the caps and the housing as left and right.
CAUTION: Be a ri n g c a p s a re machined with the
housing and must be assembled in the same
position as removed. Note the matched letter
stamped on the caps and carrier. When assembled,
the letters on the caps must agree in both the
hosizontal and vertical position with the letters on
the carrier.
420RW003
4. Remove Differential case.

Pry the case from the axle housing at the differential
ªwindowº.
420RW010
5. Remove side bearing outer races and shims.

Mark the races and shims as left and right, and
place them with the bearing cups.
6. Remove differential side bearings using remover
J±42379 and plug J±39830.

Select insert ; 303174 and collet halves ; 44801 in
remover kit J±42379.
415RW003
7. Remove ring gear bolts.

Ring gear bolts use right handed threads.
CAUTION: DO not pry the ring gear from the case.
This will damage the ring and the differential case.

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.

4B2±1
DRIVE LINE CONTROL SYSTEM (TOD)
AXIOM
DRIVELINE/AXLE
DRIVELINE CONTROL SYSTEM (TOD)
CONTENTS
Service Precaution 4B2±1. . . . . . . . . . . . . . . . . . . . . .
General Description 4B2±2. . . . . . . . . . . . . . . . . . . . .
Transfer Position and Drive Mode 4B2±2. . . . . . . .
TOD Control 4B2±3. . . . . . . . . . . . . . . . . . . . . . . . . .
TOD Indicator Control 4B2±3. . . . . . . . . . . . . . . . . .
Abbreviations 4B2±3. . . . . . . . . . . . . . . . . . . . . . . . .
System Components 4B2±4. . . . . . . . . . . . . . . . . . . .
Parts Location 4B2±4. . . . . . . . . . . . . . . . . . . . . . . .
Front and Rear Speed Sensors 4B2±5. . . . . . . . . .
Electromagnetic Coil 4B2±5. . . . . . . . . . . . . . . . . . .
Multi Plate Disk Clutch Pack 4B2±5. . . . . . . . . . . .
Mechanical Lock Sleeve 4B2±5. . . . . . . . . . . . . . . .
High-Low Planetary Gear Set 4B2±6. . . . . . . . . . .
4H and 4L Switch 4B2±6. . . . . . . . . . . . . . . . . . . . . .
Transfer Connector (12-pin type) 4B2±6. . . . . . . .
Transfer Connector (8-pin type) 4B2±6. . . . . . . . .
TOD Indicator Lamps
(on the instrument panel) 4B2±7. . . . . . . . . . . . . .
Check Lamp 4B2±7. . . . . . . . . . . . . . . . . . . . . . . . . .
TOD ECU 4B2±8. . . . . . . . . . . . . . . . . . . . . . . . . . . .
High-Low Shift Motor 4B2±9. . . . . . . . . . . . . . . . . . .
Motor Position and Encoder Position Code 4B2±10
Encode Position Plate 4B2±10. . . . . . . . . . . . . . . . . .
Shift High Range and Low Range 4B2±10. . . . . . . . Functions of TOD Switch and Indicator
Lamp 4B2±11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TOD Switch and Indication of Drive Mode 4B2±11.
Check Lamp 4B2±13. . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnosis 4B2±14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Information Diagnosis 4B2±14. . . . . . . . . .
Self-diagnosis 4B2±14. . . . . . . . . . . . . . . . . . . . . . . . .
Precautions on Diagnosis 4B2±16. . . . . . . . . . . . . . .
Basic Diagnostic Flow Chart 4B2±18. . . . . . . . . . . . . .
Parts Location 4B2±19. . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Diagram 4B2±20. . . . . . . . . . . . . . . . . . . . . . . . .
Connector List 4B2±24. . . . . . . . . . . . . . . . . . . . . . . . . .
Checking Failed Pin 4B2±26. . . . . . . . . . . . . . . . . . . . .
Connector Pin Assignment 4B2±26. . . . . . . . . . . . . .
Reference 4B2±28. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking Failed TOD Control Unit Pin 4B2±30. . . . .
Tech 2 Scan Tool 4B2±32. . . . . . . . . . . . . . . . . . . . . .
Getting Started 4B2±33. . . . . . . . . . . . . . . . . . . . . . . .
Operating Procedure 4B2±33. . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Codes 4B2±35. . . . . . . . . . . . . . . .
Diagnosis from Trouble Codes 4B2±36. . . . . . . . . . . .
Trouble Diagnosis Depending on The Status
of TOD Indicator 4B2±67. . . . . . . . . . . . . . . . . . . . . . . .
Diagnosis from Symptom 4B2±102. . . . . . . . . . . . . . . . .
Service Precaution
WARNING: THIS VEHICLE HAS A SUPPLEMENTAL
RESTRAINT SYSTEM (SRS). REFER TO THE SRS
COMPONENT AND WIRING LOCATION VIEW IN
ORDER TO DETERMINE WHETHER YOU ARE
PERFORMING SERVICE ON OR NEAR THE SRS
COMPONENTS OR THE SRS WIRING. WHEN YOU
ARE PERFORMING SERVICE ON OR NEAR THE SRS
COMPONENTS OR THE SRS WIRING, REFER TO
THE SRS SERVICE INFORMATION. FAILURE TO
FOLLOW WARNINGS COULD RESULT IN POSSIBLE
AIR BAG DEPLOYMENT, PERSONAL INJURY, OR
OTHERWISE UNNEEDED SRS SYSTEM REPAIRS.CAUTION: Always use the correct fastener in the
proper location. When you replace a fastener, use
ONLY the exact part number for that application.
ISUZU will call out those fasteners that require a
replacement after removal. ISUZU will also call out
the fasteners that require thread lockers or thread
sealant. UNLESS OTHERWISE SPECIFIED, do not
use supplemental coatings (Paints, greases, or other
corrosion inhibitors) on threaded fasteners or
fastener joint interfaces. Generally, such coatings
adversely affect the fastener torque and the joint
clamping force, and may damage the fastener. When
you install fasteners, use the correct tightening
sequence and specifications. Following these
instructions can help you avoid damage to parts and
systems.

4B2±3
DRIVE LINE CONTROL SYSTEM (TOD)
TOD Control
The TOD position usually drives the rear wheels, and
transmits the torque to the front wheels with the help of
electronically controlled torque split mechanism
according to running conditions encountered. The driving
force is directly transmitted to the rear wheels. This force
is split by the transfer and delivered to the front wheels.
The magnitude of the torque transmitted to the front
wheels is controlled by changing the pressing force of the
multi plate disk clutch built in the transfer unit. The
pressing force of the clutch is controlled by changing the
duty ratio to the electromagnetic coil mounted to the rear
of the clutch. When the clutch is completely disengaged,
the rear wheels are driven. When the clutch is completely
engaged, a rigid four wheel drive mode is obtained. The
torque split status is controlled continuously between the
rear wheel and four wheel drive modes. This system
includes front and rear speed sensors, and receives
throttle position sensor and engine speed information
from the PCM, ABS control unit signal, brake switch
signal, and shift motor position information.
The control unit receives signals sent from these sensors
and changes the pressing force of the multi-plate disk
clutch to determine the torque distribution on the front and
rear wheels. Therefore, when the slip of the rear wheels is
increased against the current torque level in the normal
rear wheel drive mode, the control unit detects the slip
condition, determines the optimum torque based on the
feedback control logic, and increases the torque to the
front wheels.
The control unit uses the signal from the throttle position
sensor to predict the future vehicle condition and the
intention of the driver with respect to acceleration and
deceleration, and determines the initial torque distribution
using these data and the information from the speed
sensors.
In case of small circle turning in the parking lot, for
example, the control unit minimizes the clutch pressing
force to restrict a braking phenomenon. When the ABS
becomes active, the control unit optimizes the clutch
pressing force to ensure stable braking.
TOD Indicator Control
The TOD indicator on the instrument panel informs the
driver of the current working status of the transfer unit.
The information is the drive mode (2H, TOD, 4L,
transition). The indicator can display occasional errors
and corresponding error codes.
Abbreviations
ABS Anti-lock Brake System
ADC Axle Disconnect
(Shift on the fly system)
VB Battery Voltage
VIGN Ignition Voltage

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±4
System Components
Parts Location
A04R200004
Legend
(1) Mechanical Lock Sleeve
(2) Drive Chain
(3) Clutch Pack
(4) Electromagnetic Clutch Solenoid
(5) Output Shaft
(6) Rear Output Coupling
(7) Rear Speed Sensor
(8) Drive Sprocket
(9) Spring
(10) Return Spring
(11) Lockup Shift Fork
(12) Front Speed Sensor
(13) High-Low Shift Motor
(14) Driven Sprocket(15) Shift Shaft
(16) Front Output Coupling
(17) Front Output Shaft
(18) Shift Cam
(19) Torsional Spring
(20) High-Low Shift Fork
(21) Shift Rod
(22) Input Shaft
(23) Reduction Hub
(24) High-Low Planetary Gear
(25) High Position
(26) Low Position
(27) Oil Pump
(28) Free Position
(29) Lock Position

4B2±5
DRIVE LINE CONTROL SYSTEM (TOD)
Front and Rear Speed Sensors
The sensors are built in the transfer case, and detect the
rotation of rotors directly coupled to the propeller shafts.
Thirty rectangular pulses are output per one rotation of
the propeller shaft.
261RW045
Electromagnetic Coil
Receives the duty signals from the TOD control unit and
controls the pressing force of the clutch pressure cam.
261RW044
Multi Plate Disk Clutch Pack
Transmits the torque determined by the clutch pressing
force to the front propeller shaft via the front drive chain.
262RW029
Mechanical Lock Sleeve
Couples the front and rear propeller shaft mechanically
when the transfer shaft is in the 4L position.
262RW028