clutch ISUZU AXIOM 2002 Service Owner's Manual

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±33
ILLUSTRATIONTOOL NO.
TOOL NAME
J±39837±1
Disc (2 required)
J±23597±1
Arbor
J±42828
Installer; Pinion bearing
J±21784
Installer; Side bearing
J±39602
Remover; Outer bearing
J±24385±B
Spreader
ILLUSTRATIONTOOL NO.
TOOL NAME
J±39858
Clutch pack unloading
tool kit Includes
J±34174±1/J±34174±2
Screw cap and Cap
J±22342±15
Forcing screw
J±39834
Limited±slip differential
(LSD) service adapter
J±39824
Holder
J±39836
Side bearing preload
master bearings

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

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±8
TOD ECU
This control unit is mounted to the clutch pedal position
via a special bracket.
826R200019
Legend
(1) Brake Pedal Bracket

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±26
Checking Failed Pin
Connector Pin Assignment

TOD control unit pin assignment
D04RY00011
No.NAMECONTENTS
1N.C Not used
2ENG REVEngine Speed
3N.CNot used
4N.CNot used
5N.C Not used
6N.CNot used
7IND.ADisplay Front
8IND. CDisplay Rear
9N.C Not used
10N.C Not used
11EMCClutch Solenoid
12REFSpeed Reference
13COM (±)Speed GND
14VIGIgnition
15TPSTPS (PWM)
16TECH 2TECH±2
17N. CNot used
18N. CNot used
19IND. BDisplay Auto
20CHK TODCheck TOD
21N.CNot used
22PWR GNDPower Ground
23ADC (+)Axle Disconnect Output
24COM GNDShift Motor Position GND
25MTR POS3Shift Motot Position 3

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±54
StepActionYe sNo
11. Clear the trouble code.
2. Start the engine
3. Set the TOD mode.
Is there DTC31 (P1721)?
Go to Step 2
Refer to ªTrouble
intermittently
observedº.
21. Turn off the starter switch.
2. Disconnect the ECU connector from ECU.
Is the continuity established between terminals (C±38)11 and
(C±38)22?
Go to Step 3Go to Step 5
31. Connect the ECU connector.
2. Start the engine.
3. Set the TOD mode.
Does the voltage between terminals 11 and 22 indicate at least
0.4V?
Go to Step 4Go to Step 6
4Is the battery voltage always observed between terminals 11 and
22?The harness is
short±circuited on
the battery.
Repair the circuit.
Go to
Step 8Go to Step 6
51. Disconnect the A±1 connector.
Is the continuity established between transfer connector
terminals (A±1)8 and (A±1)7?
The harness is
broken. Repair
the circuit.
Go to
Step 8
Replace the
transfer
electromagnetic
coil (solenoid
clutch).
Go to
Step 8
61. Turn off the starter switch.
2. Disconnect the ECU connector from ECU.
Is the resistance between the connector (C±38) terminal 11 and
22 1.0 ~ 5.0
?The ECU has
failed. Replace
the ECU
Go to
Step 8Go to Step 7
7Is the resistance between the transfer connector (A±1) terminal 8
and 7 1.0 ~ 5.0
?
The harness is
disconnection or
short to GND.
Repair the circuit.
Go to
Step 8
Replace the
transfer
electromagnetic
coil (solenoid
clutch).
Go to
Step 8
81. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Repeat the
ªDiagnosis Flowº.
Return to Step 8