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TRANSFER CASE 7D-37
ILLUSTRATION PART NO.
PART NAME
5-8840-2787-0
Snapring installer
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TRANSFER CONTROL SYSTEM 7D1-1
SECTION 7D1
TRANSFER CONTROL SYSTEM
TABLE OF CONTENTS
PAGE
Service Precaution .................................................................................................... 7D1 - 2
General Description ................................................................................................... 7D1 - 3
System Components ................................................................................................. 7D1 - 5
Parts Location ...................................................................................................... 7D1 - 5
Functions of Switch and Indicator Lamp ................................................................. 7D1 - 11
Parts Location ............................................................................................................ 7D1 - 23
Circuit Diagram .......................................................................................................... 7D1 - 27
Connector List ........................................................................................................... 7D1 - 31
Diagnosis .................................................................................................................... 7D1 - 34
Before determining trouble ................................................................................. 7D1 - 34
Memory erasing procedure ....................................................................................... 7D1 - 40
Diagnosis from symptom .......................................................................................... 7D1 - 41
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7D1-2 TRANSFER CONTROL SYSTEM
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.
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TRANSFER CONTROL SYSTEM 7D1-3
General Description
RTW47DLF000301
Transfer Position and Drive Mode
Three drive modes can be selected through operation of 4WD switch.
Transfer Position 4WD SWITCH Mode Drive mode
2H RWD Rear wheel drive
HIGH
4H 4WD (HIGH) High-speed mechanical
lock-up four wheel drive
LOW 4L 4WD (LOW) Low-speed mechanical
lock-up four wheel drive
NEUTRAL 2H & 4L (10 Sec) NEUTRAL Towed by other vehicle
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7D1-4 TRANSFER CONTROL SYSTEM
Summary of transfer control system
The transfer control system switches between the 2-wheel
drive (2H), 4-wheel drive high-speed (4H), 4-wheel drive low-
speed (4L), and neutral positions electrically when the driver
operate the switches.
This system has following functions.
1. Connection or disconnection of drive force distribution to
the front wheel front shaft (axle shaft) (The drive force
distribution to the front propeller is connected o
r
disconnected with the motor actuator.)
2. Try to repeat the connection or disconnection of the front
wheel drive function as described above.
3. Option: Shift on the fly type only.
Instruction of connection or disconnection of the drive force
transmission between the front wheel axle (axle shaft) and
front wheel
(The motor actuator connects or disconnects the left front
wheel ad front wheel axle (axle shaft).).
4. Shifting of auxiliary transmission gears, connection o
r
disconnection of wheel and engine drive force (4H, 4L,
neutral).
5. Operation of indicator on the instrument panel.
6. Transmission of position signal to other controllers.
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TRANSFER CONTROL SYSTEM 7D1-5
System Components
Parts Location
Speed sensor
Revolutions of the rear output shaft are decreased and taken
out by the speed/drive/driven gears installed in the transfer
case and the number of revolutions is detected with a speed
sensor.
About 4/3 pulses per revolution of the shaft is output.
4WD switch
The 4WD switch detects the movement of the shift rod driving
the 4
2 - 4
4 sleeve.
PUSH open is achieved with the PUSH open switch when the
shift rod is at the 42 position.
4
2 - 4
4 sleeve & Arm
The 42 - 44 sleeve moves directly in the 44 direction with
the 4
2 - 4
4 shift rod, but, when moving in 4
2 direction, a
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7D1-6 TRANSFER CONTROL SYSTEM
spring standby mechanism is provided between the rod and
sleeve so that the rod is positioned at the 4
2 position, while
the sleeve is at the 44 position in sometime.
This mechanism is provided to protect the shift mechanism
from the force to prevent the movement of the sleeve
(torsional torque etc. of the drive system). By releasing the
preventive force, the sleeve can move to 4
2 state by the
spring force.
Neutral switch
The neutral switch detects the movement of the shift rod
driving the high-low sleeve.
PUSH close is achieved with the PUSH close switch when the
shift rod is positioned between the High and the Low, that is,
at the neutral state.
High-Low Sleeve & Arm
The spring standby mechanism is provided for the high-low
sleeve in both directions of the high-low shift rod. For this
reason, the rod position and the actual sleeve position may be
offset in some cases.
This system is provided to protect the shift mechanism from
the collision due to coincidence of the high and low phases of
the engaged splines. By giving rotational force to the
preventing phase coincidence, the splines are moved to the
proper engagement position by the spring force.
Shift actuator
The output shaft is rotated by the built-in motor and the
transfer position is switched.
Detection (limit) switches to detect the rotating angle of the
output shaft is provided to the actuator at 4 positions, which
are connected to the transfer controller through the vehicle
harness to constantly transmit the actuator operating angle
and changes in its transfer status.
7B4-PDF2
4WD indicator (in meter panel)
This lamp indicates the following items
Valve check
Drive condition (2WD-4WD)
Operating condition (2Hz: Actuator in operation, mechanism
standby)
Restrictions on operation (4Hz, including indication of
interrupted operation due
to excessive load)
4L indicator (in meter panel)
This lamp indicates following items.
Valve check
Driving status (High-Low)
Operating status (2Hz: Actuator in operation, mechanism
standby)
Restrictions on operation (4Hz)