2006 INFINITI QX56 clutch

TF-2Revision: November 20092006 QX56
REFERENCE VALUE .......................................
... 54
DIAGNOSTIC PROCEDURE ........................... ... 55
COMPONENT INSPECTION ........................... ... 57
Transfer Control Unit ........................................... ... 57
DIAGNOSTIC PROCEDURE ........................... ... 57
Output Shaft Revolution Signal (TCM) ................ ... 58
DIAGNOSTIC PROCEDURE ........................... ... 58
Vehicle Speed Sensor (ABS) ............................... ... 58
DIAGNOSTIC PROCEDURE ........................... ... 58
Neutral-4LO Switch ................................................ 59 CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ............................................. ... 59
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ....................................... ... 59
DIAGNOSTIC PROCEDURE ........................... ... 60
COMPONENT INSPECTION ........................... ... 62
4WD Shift Switch ................................................. ... 62
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ............................................. ... 62
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ....................................... ... 62
DIAGNOSTIC PROCEDURE ........................... ... 63
COMPONENT INSPECTION ........................... ... 66
Wait Detection Switch .......................................... ... 66
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ............................................. ... 66
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ....................................... ... 66
DIAGNOSTIC PROCEDURE ........................... ... 67
COMPONENT INSPECTION ........................... ... 69
PNP Switch Signal (TCM) ................................... ... 69
DIAGNOSTIC PROCEDURE ........................... ... 69
Actuator Motor ..................................................... ... 70
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ............................................. ... 70
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ....................................... ... 70
DIAGNOSTIC PROCEDURE ........................... ... 71
COMPONENT INSPECTION ........................... ... 76
Actuator Position Switch ...................................... ... 77
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ............................................. ... 77
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ....................................... ... 77
DIAGNOSTIC PROCEDURE ........................... ... 78
COMPONENT INSPECTION ........................... ... 80
Transfer Control Device ....................................... ... 81
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ............................................. ... 81
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ....................................... ... 81
DIAGNOSTIC PROCEDURE ........................... ... 82
Engine Speed Signal (ECM) ................................ ... 85
DIAGNOSTIC PROCEDURE ........................... ... 85
Clutch Pressure Solenoid .................................... ... 86
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ............................................. ... 86
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ....................................... ... 86DIAGNOSTIC PROCEDURE ............................
... 87
COMPONENT INSPECTION ............................ ... 90
2-4WD Solenoid ................................................... ... 91
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ............................................. ... 91
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ....................................... ... 91
DIAGNOSTIC PROCEDURE ............................ ... 91
COMPONENT INSPECTION ............................ ... 94
Transfer Motor ...................................................... ... 95
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ............................................. ... 95
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ....................................... ... 96
DIAGNOSTIC PROCEDURE ............................ ... 97
COMPONENT INSPECTION ............................ .102
Transfer Fluid Temperature .................................. .102
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ............................................. .102
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ....................................... .102
DIAGNOSTIC PROCEDURE ............................ .103
COMPONENT INSPECTION ............................ .104
Clutch Pressure Switch ........................................ .105
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ............................................. .105
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ....................................... .105
DIAGNOSTIC PROCEDURE ............................ .106
COMPONENT INSPECTION ............................ .107
Line Pressure Switch ........................................... .108
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ............................................. .108
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ....................................... .108
DIAGNOSTIC PROCEDURE ............................ .109
COMPONENT INSPECTION ............................ .110
Throttle Position Signal (ECM) ............................. . 111
DIAGNOSTIC PROCEDURE ............................ . 111
ABS Operation Signal (ABS) ............................... . 111
DIAGNOSTIC PROCEDURE ............................ . 111
VDC Operation Signal (ABS) ............................... .112
DIAGNOSTIC PROCEDURE ............................ .112
TCS Operation Signal (ABS) ............................... .112
DIAGNOSTIC PROCEDURE ............................ .112
CAN Communication Line .................................... .113
DIAGNOSTIC PROCEDURE ............................ .113
ATP Switch ........................................................... .113
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ............................................. .113
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ....................................... .113
DIAGNOSTIC PROCEDURE ............................ .114
COMPONENT INSPECTION ............................ .115
TROUBLE DIAGNOSIS FOR SYMPTOMS ........... .117
4WD Shift Indicator Lamp and 4LO Indicator Lamp
Do Not Turn ON ................................................... .117
SYMPTOM: ....................................................... .117
DIAGNOSTIC PROCEDURE ............................ .117

TF-3
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Revision: November 2009 2006 QX56
4WD Warning Lamp Does Not Turn ON .............
. 121
SYMPTOM: ...................................................... . 121
DIAGNOSTIC PROCEDURE ........................... . 121
4WD Shift Indicator Lamp or 4LO Indicator Lamp
Does Not Change ................................................ . 123
SYMPTOM: ...................................................... . 123
DIAGNOSTIC PROCEDURE ........................... . 124
ATP Warning Lamp Turns ON ............................. . 125
SYMPTOM: ...................................................... . 125
DIAGNOSTIC PROCEDURE ........................... . 125
4LO Indicator Lamp Repeats Flashing ................ . 127
SYMPTOM: ...................................................... . 127
DIAGNOSTIC PROCEDURE ........................... . 127
4WD Warning Lamp Flashes Rapidly ................. . 128
SYMPTOM: ...................................................... . 128
DIAGNOSTIC PROCEDURE ........................... . 128
4WD Warning Lamp Flashes Slowly ................... . 129
SYMPTOM: ...................................................... . 129
DIAGNOSTIC PROCEDURE ........................... . 129
Heavy Tight-corner Braking Symptom Occurs .... . 130
SYMPTOM: ...................................................... . 130
DIAGNOSTIC PROCEDURE ........................... . 130
4WD System Does Not Operate ......................... . 131
SYMPTOM: ...................................................... . 131
DIAGNOSTIC PROCEDURE ........................... . 131
TRANSFER CONTROL UNIT ................................ . 132
Removal and Installation ..................................... . 132
REMOVAL ........................................................ . 132
INSTALLATION ................................................ . 132
FRONT OIL SEAL ................................................. . 133
Removal and Installation ..................................... . 133
REMOVAL ........................................................ . 133
INSTALLATION ................................................ . 134
REAR OIL SEAL ................................................... . 135
Removal and Installation ..................................... . 135
REMOVAL ........................................................ . 135
INSTALLATION ................................................ . 135SIDE OIL SEAL ......................................................
.137
Removal and Installation ..................................... .137
REMOVAL ........................................................ .137
INSTALLATION ................................................ .137
TRANSFER CONTROL DEVICE ........................... .138
Removal and Installation ..................................... .138
AIR BREATHER HOSE ......................................... .139
Removal and Installation ..................................... .139
TRANSFER MOTOR .............................................. .142
Removal and Installation ..................................... .142
REMOVAL ........................................................ .142
INSTALLATION ................................................ .142
TRANSFER OIL FILTER ........................................ .143
Removal and Installation ..................................... .143
REMOVAL ........................................................ .143
INSTALLATION ................................................ .143
TRANSFER ASSEMBLY ....................................... .145
Removal and Installation ..................................... .145
REMOVAL ........................................................ .145
INSTALLATION ................................................ .145
Disassembly and Assembly ................................. .146
COMPONENTS ................................................ .146
DISASSEMBLY ................................................ .148
INSPECTION AFTER DISASSEMBLY ............. .163
ASSEMBLY ...................................................... .167
SERVICE DATA AND SPECIFICATIONS (SDS) ... .183
General Specifications ......................................... .183
Inspection and Adjustment .................................. .183
CLEARANCE BETWEEN INNER GEAR AND
OUTER GEAR .................................................. .183
CLUTCH ........................................................... .183
PINION GEAR END PLAY ............................... .183
CLEARANCE BETWEEN SHIFT FORK AND
SLEEVE ........................................................... .183
SELECTIVE PARTS ......................................... .183

TF-12
ALL-MODE 4WD SYSTEM
Revision: November 20092006 QX56
ALL-MODE 4WD SYSTEMPFP:00000
Cross-section ViewEDS002H8
1. Center case2. Front case 3. Internal gear
4. Planetary carrier assembly 5. Sun gear assembly 6. Main shaft
7. L-H sleeve 8. L-H fork 9. Shift rod
10. 2-4 sleeve 11. 2-4 fork 12. Drive chain
13. Front drive shaft 14. Control valve assembly 15. Transfer motor
16. Rear case 17. Clutch piston 18. Press flange
19. Multiple disc clutch 20. Clutch hub assembly 21. Clutch drum assembly
WDIA0202E

ALL-MODE 4WD SYSTEMTF-13
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Power TransferEDS002H9
POWER TRANSFER DIAGRAM
1. Center case2. Chain3. Multiple disc clutch
4. Rear case 5. Mainshaft6. Clutch hub assembly
7. Sub oil pump 8. Transfer motor9. Control valve
10. Front drive shaft 11. Drain plug12. 2-4 sleeve
13. Sun gear assembly 14. L-H sleeve15. Planetary carrier assembly
16. Internal gear 17. Front case
LDIA0053E

ALL-MODE 4WD SYSTEMTF-17
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Transfer Motor Relay Operation
*: After 2.5 seconds have elapsed.

4WD shift switch, PNP switch, Neutral-4LO switch, vehicle speed sensor and throttle position sensor are
used in conjunction with the transfer motor.
WAIT DETECTION SWITCH

The wait detection switch operates when there is “circulating” torque produced in the propeller shaft
(L → H) or when there is a phase difference between 2-4 sleeve and clutch drum (H →L). After the release
of the “circulating ” torque, the wait detection switch helps provide the 4WD lock gear (clutch drum) shifts.
A difference may occur between the operation of the 4WD shift switch and actual drive mode. At this
point, the wait detection switch senses an actual drive mode.

The wait detection switch operates as follows.
–4WD lock gear (clutch drum) locked: ON
–4WD lock gear (clutch drum) released: OFF

The wait detection switch senses an actual drive mode and the 4WD shift indicator lamp indicates the
vehicle drive mode.
NEUTRAL-4LO SWITCH
The neutral-4LO switch detects that transfer gear is in neutral or 4LO (or shifting from neutral to 4LO) condi-
tion by L-H shift fork position.
AT P S W I T C H
ATP switch detects if transfer gear is in a neutral condition by L-H shift fork position.
NOTE:
Transfer gear may be in a neutral condition in 4H-4LO.
2-4WD SHIFT SOLENOID VALVE
The 2-4WD shift solenoid valve operates to apply oil pressure to the wet-multiplate clutch, depending on the
drive mode. The driving force is transmitted to the front wheels through the clutch so the vehicle is set in the
4WD shift switch A/T selector lever position Vehicle speed
(VSS) Accelerator pedal position Motor relay drive
command
2WD ——— OFF
4H (LOCK) and 4LO “
N ” position 0— ON
“ P ” position 00 - 0.07/8
OFF*
0.07/8 - 1/8 HOLD
1/8 - MAX ON
Other than “ R” position 0 < VSS
≤ 50 km/h (31 MPH)
— ON
50 km/h (31 MPH) < VSS < 55 km/h (34 MPH) HOLD
55 km/h (34 MPH) ≤ VSS OFF
“ R ” position —— ON
“ R ” position —— ON
AUTO “
P ” or “ N” position 0
0 - 0.07/8
OFF*
0.07/8 - 1/8 HOLD
1/8 - MAX ON
0 < VSS ≤ 50 km/h (31 MPH)
— ON
50 km/h (31 MPH) < VSS < 55 km/h (34 MPH) HOLD
55 km/h (34 MPH) ≤ VSS OFF
Other than “ R”, "P" and "N"
position 0 < VSS
≤ 50 km/h (31 MPH)
— ON
50 km/h (31 MPH) < VSS < 55 km/h (34 MPH) HOLD
55 km/h (34 MPH) ≤ VSS OFF

TF-18
ALL-MODE 4WD SYSTEM
Revision: November 20092006 QX56
4WD mode. Setting the vehicle in the 2WD mode requires no pressure buildup. In other words, pressure force
applied to the wet-multiplate clutch becomes zero.
CLUTCH PRESSURE SOLENOID VALVE
The clutch pressure solenoid valve distributes torque (front and rear) in AUTO mode.
LINE PRESSURE SWITCH

With the transfer system design, control of the oil pressure provides the transmission of drive torque to the
front wheels. The main pressure to control the oil pressure is referred to as the line pressure.

The line pressure switch determines whether or not adequate line pressure has built up under different
operating conditions.

The line pressure switch turns ON when line pressure is produced.

The line pressure switch senses line pressure abnormalities and turns the 4WD warning lamp ON.
CLUTCH PRESSURE SWITCH

The clutch pressure switch determines whether or not adequate clutch pressure has built up under differ-
ent operating conditions.

The clutch pressure switch turns ON when clutch pressure is produced.

The clutch pressure switch senses clutch pressure abnormalities and turns the 4WD warning lamp ON.
TRANSFER FLUID TEMPERATURE SENSOR
The transfer temperature sensor detects the transfer fluid temperature and sends a signal to the transfer con-
trol unit.
TRANSFER CONTROL UNIT

Transfer control unit controls transfer control device by input signals of each sensor and each switch.

Self-diagnosis can be done.
TRANSFER CONTROL DEVICE
The transfer control device changes the state of transfer assembly between 2WD, AUTO, 4H⇔4LO with the
2WD, AUTO, 4H and 4LO signals of 4WD shift switch.
NOTE:

To shift between 4H ⇔4LO, stop the vehicle, depress the brake pedal and shift the transmission selector
to the "N" position. Depress and turn the 4WD shift switch. The shift switch will not shift to the desired
mode if the transmission is not in "N" or the vehicle is moving. The 4LO indicator lamp will be lit when the
4LO is engaged.

Actuator motor and actuator position switch are integrated.
4WD SHIFT SWITCH AND INDICATOR LAMP
4WD Shift Switch
The 4WD shift switch allows selection from 2WD, AUTO, 4H or 4LO.
4WD Shift Indicator Lamp

Displays driving conditions selected by 4WD shift switch with 2WD, AUTO and 4H indicators while engine
is running. (When 4WD warning lamp is turned on, all 4WD shift indicator lamps are turned off.)

Turns ON for approximately 1 second when ignition switch is turned ON, for purpose of lamp check.
4LO Indicator Lamp

Displays 4LO condition while engine is running. 4LO indicator lamp flashes if transfer gear does not shift
completely under 2WD, AUTO, 4H ⇔4LO. (When 4WD warning lamp is turned on, 4LO indicator lamp is
turned off.)

Turns ON for approximately 1 second when ignition switch is turned ON, for purpose of lamp check.

TF-20
ALL-MODE 4WD SYSTEM
Revision: November 20092006 QX56
COMPONENTS FUNCTION
CAN CommunicationEDS002HC
SYSTEM DESCRIPTION
Refer to LAN-26, "CAN COMMUNICATION" .
Component parts Function
Transfer control unit Controls transfer control device and control valves.
Transfer control device Actuator motor and actuator position switch are integrated so as to switch driving types.
2-4WD shift solenoid valve Controls oil pressure and allows selection between 2WD and 4WD.
Clutch pressure solenoid valve Controls oil pressure and distributes torque (front and rear).
Line pressure switch Detects line pressure.
Clutch pressure switch Detects clutch pressure.
Transfer fluid temperature sen-
sor Detects transfer fluid temperature.
Wait detection switch Detects whether or not 4WD lock gear is locked.
Neutral-4LO switch Detects that transfer is under neutral-4LO condition (or shifting through neutral).
ATP switch Detects that transfer is under neutral condition.
4WD shift switch Allows selection from 2WD, AUTO, 4H or 4LO.
4WD warning lamp

Illuminates if malfunction is detected in electrical system of 4WD system.

There is 1 blink every 2 seconds if rotation difference of front wheels and rear wheels is large.

There is 2 blinks every 1 second if high transfer fluid temperature is detected.
ATP warning lamp Indicates that A/T parking mechanism does not operate when A/T selector lever is in
“P ” position
and transfer is under neutral condition.
4WD shift indicator lamp Displays driving condition selected by 4WD shift switch.
4LO indicator lamp Displays 4LO condition.
ABS actuator and electric unit
(control unit) Transmits vehicle speed signal via CAN communication to transfer control unit.
TCM Transmits the following signals via CAN communication to transfer control unit.

Output shaft revolution signal

A/T position indicator signal (PNP switch signal)
ECM Transmits the following signals via CAN communication to transfer control unit.

Engine speed signal

Accelerator pedal position signal

TROUBLE DIAGNOSISTF-35
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NOTE:

Light tight-corner braking symptom may occur depending on driving conditions in AUTO mode. This is not
a malfunction.

Heavy tight-corner braking symptom occurs when vehicle is driven in the following conditions: 4WD shift
switch is "4H" or "4LO", steering wheel is turned fully to either side.
Transfer Control Unit Input/Output Signal Reference ValuesEDS002HJ
TRANSFER CONTROL UNIT INSPECTION TABLE
Specifications with CONSULT-II
4WD warning lamp flashes slowly
(1 time/2 seconds)While drivingTire size is different between front and
rear of vehicle.
TF-129
Transfer fluid temperature
Clutch pressure switch
Heavy tight-corner braking symptom occurs
(See NOTE.)

While driving

AUTO mode

Steering wheel is
turned fully to either
side CAN communication line
TF-130
4WD shift switch
Accelerator pedal position signal
Clutch pressure solenoid
Transfer inner parts
4WD system does not operate While driving 4WD shift switch
TF-131
Clutch pressure switch
Transfer inner parts
Symptom
ConditionCheck itemReference page
Monitored item [Unit] Content ConditionDisplay value
VHCL/S SEN ·FR [km/h]
or [mph] Front wheel speed Vehicle stopped
0 km/h (0 MPH)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition. Approximately
equal to the indi-
cation on speed-
ometer (Inside of
±
10%)
VHCL/S SEN ·RR [km/h]
or [mph] Rear wheel speed Vehicle stopped
0 km/h (0 MPH)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition. Approximately
equal to the indi-
cation on speed-
ometer (Inside of
±
10%)
ENGINE SPEED [rpm] Engine speed Engine stopped
(Engine speed: Less than 400 rpm)
0 rpm
Engine running
(Engine speed: 400 rpm or more) Approximately
equal to the indi-
cation on tachom-
eter
THRTL POS SEN [V] Accelerator pedal posi-
tion (APP) sensor signal
voltage Accelerator pedal: Release
Approx. 0.5V
Accelerator pedal: Fully depressed Approx. 4.0V
FLUID TEMP SE [V] Transfer fluid tempera-
ture signal voltage Transfer fluid temperature approx. 20 - 80°C (68 - 176
°F) Approx. 1.1 - 0.3V
BATTERY VOLT [V] Power supply voltage for
transfer control unit
Ignition switch: ON
Battery voltage
2WD SWITCH [ON/OFF] Input condition from
4WD shift switch 4WD shift switch: 2WD
ON
4WD shift switch: AUTO, 4H or 4LO OFF
AUTO SWITCH [ON/
OFF] Input condition from
4WD shift switch 4WD shift switch: AUTO
ON
4WD shift switch: 2WD, 4H or 4LO OFF