1998 ISUZU TROOPER 4WD

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±80
StepActionYe sNo
1Start the engine.
When the transfer lever is shifted to the neutral position between
high and 4L, is 5V observed between terminals 10 and 19?
Go to Step 2Go to Step 7
2When the transfer lever is shifted to the high position and 4WD
switch shifted to 4WD position, is 0V observed between terminals
10 and 19?
Go to Step 3Go to Step 7
3When the transfer lever is shifted to the 4L position, is 0V
observed between terminals 10 and 19?
Go to Step 4Go to Step 7
4Select the 4WD SW to the 2WD position.
Is 12V observed between terminals 25 and 19?
Go to Step 5Go to Step 19
5Is 12V observed between terminals 26 and 19?Go to Step 6Go to Step 19
6Is 12V observed between terminals 27 and 19?The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
Go to Step 19
The ECU has
failed. Replace
the ECU.
Go to Step 19
7When the 4WD SW is select to the 2WD position, is the battery
voltage observed between terminals 5 and 19?
Go to Step 8Go to Step 11
8When the transfer lever is shifted to the neutral position between
high and 4L, is the battery voltage observed between terminals 5
and 19?
Go to Step 9Go to Step 11
9When the transfer lever is shifted to the high position and 4WD
switch shifted to 4WD position, is 0V observed between terminals
5 and 19?
Go to Step 10Go to Step 11
10When the transfer lever is shifted to the 4L position, is 0V
observed between terminals 5 and 19?
Go to Step 12Go to Step 11
11Is any of the trouble codes 28, 32 and 33 recorded?Examine the
trouble based on
ªDiagnosis from
Trouble Codesº.
Go to Step 19
The ECU has
failed. Replace
the ECU.
Go to Step 19
121. Turn off the starter switch.
2. Disconnect the ECU connector.
Does the resistance between terminals (B±67)5 and (B±67)11
meet the standard, 17< R < 25 ohm?
Go to Step 13
Repair the circuit
or replace the
VSV.
Go to Step 19
131. Connect the ECU connector.
2. Turn on the starter switch.
When the 4WD SW is select to the 2WD position, is the battery
voltage supplied to each VSV?
Go to Step 14
Repair the circuit
or replace the
VSV.
Go to Step 19
14When the transfer lever is shifted to the neutral position between
high and 4L, is the battery voltage supplied to each VSV?
Go to Step 15
Repair the circuit
or replace the
VSV.
Go to Step 19
15When the transfer lever is shifted to the high position and 4WD
switch shifted to 4WD position, is 0V observed on each VSV?
Go to Step 16
Repair the circuit
or replace the
VSV.
Go to Step 19

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±86
Diagnosis from Symptom
Troubles that are not indicated by the warning lamp are
listed in the table below. These troubles are caused by
the faults that cannot be detected by the self-diagnostic
function of the control unit.
If this type of trouble is observed, interview the customer
and conduct test runs to reproduce the trouble,cross-check the reported trouble with the listed
phenomena, and diagnose and analyze the trouble on the
item by item basis.
PhenomenaMajor causeCorrective action
1The tight corner braking is ob-
served when the vehicle is subject
to full steering.
The standard tires are not used.

The tire pressure is incorrect.

The tires are worn inuniformity.

The transfer or wiring is
imperfect.

The limited slip differential is
failed.Check and recondition the ve-
hicle according to Chart 1.
2Even if the 4WD SW is select to the
4WD position, the 4WD mode is not
active, resulting in remarkable rear
wheel spin.
The transfer or wiring is
imperfect.

The shift on the fly system is
failed.Check and recondition the ve-
hicle according to Chart 2.
3
When the 4WD SW is select to
the 4WD position, the drive
resistance of the 4WD system is
too large to get sufficient running
speed.

Noised drive line.
The standard tires are not used.

The tire pressure is incorrect.

The tires are worn inuniformity.

The transfer or wiring is
imperfect.

The limited slip differential is Check and recondition the ve-
hicle according to Chart 1.
4The shift on the fly system (front
axle) generates gear noises.
The wiring is imperfect.

The full automatic free wheel
hub is failed.Check and recondition the ve-
hicle according to Chart 3.
5The braking distance gets long
even when the ABS is active.
The wiring is imperfect.

The ABS is failed.Check and recondition the ve-
hicle according to Chart 4.

4B2±89 DRIVE LINE CONTROL SYSTEM (TOD)
StepNo Ye s Action
131. Apply the brake and fully turn the steering to the left (or right)
end, and start the creep run.
Does the voltage between terminals 4 and 20 range between 0.1
and 1.0V?Repair the
transfer
assembly.
Go to Step 16The ECU has
failed. Replace
the ECU.
Go to Step 16
141. Shift the transfer lever to the high (TOD) position.
2. Fully turn the steering to the left (or right) end, and select the D
range and start the creep run.
Does the voltage between terminals 4 and 20 range between 0.1
and 1.0V?
Go to Step 15 Go to Step 13
151. Select the 4WD SW to the 2WD position.
2. Jack up the right front wheel.
Does the front tire rotate smoothly?
Repair the
transfer
assembly.
Go to Step 16
The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
Go to Step 16
16Check that all the parts are mounted.
Is this step complete?Repeat the
ªDiagnosis Flowº.
Return to Step 16
*NOTE: Before checking this item, run the vehicle more
than 10 meters with the steering wheel in straight position
so that the 4L mechanical lock sleeve can be released
certainly.

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±90
Chart 2The 4WD mode is not active.
Function of circuitÐ
Fail conditionThe rear wheels spin in the TOD mode, so the driving torque is not transmitted to the
front wheels. The indicator lamps will not show the 4L and TOD status.
D04RW057

4B2±93 DRIVE LINE CONTROL SYSTEM (TOD)
StepActionYe sNo
1Do the indicator lamps show the correct status?
Go to Step 2
Examine the
trouble based on
ªDiagnosis from
Trouble Codesº.
Go to Step 2
2Is any of the trouble codes 28, 32 and 33 recorded?Examine the
trouble based on
ªDiagnosis from
Trouble Codesº.
Go to Step 6
Go to Step 3
3Turn on the starter switch.
Is the battery voltage observed between terminals 1 and 20?
Go to Step 4Go to Step 5
4When the 4WD SW is select to the 2WD position, are the front
axle gears correctly disengaged (and when the left front tire is
jacked up and turned, is the front propeller shaft standstill)?The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
Go to Step 6
The shift on the
fly system is
failed (refer to
Section 4C ªDrive
Shaft Systemº.
Go to Step 6
5Does the battery voltage maintain the correct level?
Repair the battery
circuit.
Go to Step 6
Repair the battery
and charging
system.
Go to Step 6
6Check that all the parts are mounted.
Is this step complete?Repeat the
ªDiagnosis Flowº.
Return to Step 6

DRIVE LINE CONTROL SYSTEM (TOD) 4B2–95
Step Action Yes No
1 Are the brake and ABS systems healthy?
Go to Step 2Repair the
brake and ABS.
Go to Step 4
2 Turn on the star ter switch.
Is the battery voltage observed between terminals 1 and 20?
Go to Step 3Repair the
battery system.
Go to Step 4
3 1. Select the 4WD SW to the 2WD position.
2. The voltage between terminals 3 and 19 range between 7.5
and 16V (0.24 seconds make a cycle)
Does the voltage within the range specified?Examine the
trouble based
on “Diagnosis
from Trouble
Codes".
Go to Step 4The ECU has
failed. Replace
the ECU.
Go to Step 4
4 Check that all the par ts are mounted.
Is this step complete?Repeat the
“Diagnosis Flow". Return to Step 4

TRANSFER CASE (STANDARD TYPE)
4D1±1
DRIVELINE/AXLE
TRANSFER CASE (STANDARD TYPE)
CONTENTS
Service Precaution 4D1±1. . . . . . . . . . . . . . . . . . . . . .
General Description 4D1±2. . . . . . . . . . . . . . . . . . . . .
Transfer Rear Oil Seal 4D1±8. . . . . . . . . . . . . . . . . . .
Removal 4D1±8. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 4D1±8. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transfer Case Assembly 4D1±9. . . . . . . . . . . . . . . . .
Removal 4D1±9. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 4D1±10. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transfer Rear Cover Assembly
(4WD Switch Model) 4D1±11. . . . . . . . . . . . . . . . . . . .
Transfer Rear Cover Assembly and
Associated Parts 4D1±11. . . . . . . . . . . . . . . . . . . . . .
Removal 4D1±12. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 4D1±13. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disassembly 4D1±16. . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 4D1±17. . . . . . . . . . . . . . . . . .
Reassembly 4D1±17. . . . . . . . . . . . . . . . . . . . . . . . . .
Transfer Rear Cover Assembly
(Except 4WD Switch Model) 4D1±19. . . . . . . . . . . . . . Transfer Rear Cover Assembly and
Associated Parts 4D1±19. . . . . . . . . . . . . . . . . . . . . .
Removal 4D1±20. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 4D1±20. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disassembly 4D1±23. . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 4D1±24. . . . . . . . . . . . . . . . . .
Reassembly 4D1±24. . . . . . . . . . . . . . . . . . . . . . . . . .
Detent, Shift Arm, and Interlock Pin 4D1±26. . . . . . . .
Disassembled View 4D1±26. . . . . . . . . . . . . . . . . . . .
Disassembly 4D1±26. . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 4D1±28. . . . . . . . . . . . . . . . . .
Reassembly 4D1±28. . . . . . . . . . . . . . . . . . . . . . . . . .
Transfer Case Assembly 4D1±30. . . . . . . . . . . . . . . . .
Disassembled View 4D1±30. . . . . . . . . . . . . . . . . . . .
Disassembly 4D1±31. . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 4D1±33. . . . . . . . . . . . . . . . . .
Reassembly 4D1±37. . . . . . . . . . . . . . . . . . . . . . . . . .
Main Data and Specifications 4D1±43. . . . . . . . . . . . .
Special Tools 4D1±46. . . . . . . . . . . . . . . . . . . . . . . . . . .
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.

4D1±2
TRANSFER CASE (STANDARD TYPE)
General Description
M/T, W/Shift On The Fly, W/4WD Switch, model
A07RW019