oil pressure INFINITI QX56 2004 Factory Service Manual

REAR SUSPENSION MEMBER
RSU-31
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Revision: August 20072004 QX56
Rear Load Leveling Air Suspension System
REMOVAL
1. Use the CONSULT-II “EXHAUST SOLENOID” active test to release the air pressure from the rear load
leveling air suspension system.
2. Disconnect the electrical connectors for the height sensor and the rear load leveling air suspension com-
pressor assembly.
3. Unclip the rubber cover to access the rear load leveling air suspension compressor assembly.
1. Seat belt latch anchor 2. Stabilizer bar bushing 3. Stabilizer bar clamp
4. Stabilizer bar 5. Connecting rod 6. Front lower link
7. Knuckle 8. Bushing 9. Rear lower link
10. Shock absorber 11. Suspension arm 12. Lower rubber seat
13. Coil spring 14. Upper rubber seat 15. Rear suspension member
16. Spare tire bracket 17. Bound bumper
LEIA0072E
1. Rear load leveling air suspension
hose, RH2. Shock absorber, RH 3. Height sensor
4. Rear load leveling air suspension
hose, LH5. Shock absorber, LH 6. Rear load leveling air suspension
compressor assembly (includes the
bracket and rubber cover)

REAR LOWER LINK & COIL SPRING
RSU-39
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Revision: August 20072004 QX56
REAR LOWER LINK & COIL SPRINGPFP:551B0
Removal and Installation EES0011P
REMOVAL
1. Remove the wheel and tire assembly using power tool. Refer to WT-6, "Rotation" .
2. Use CONSULT-II "EXHAUST SOLENOID" active test to release the air pressure from the rear load level-
ing air suspension system.
3. For removing the LH rear lower link and coil spring, remove the
height sensor arm bracket bolt from the LH rear lower link.
4. Set a suitable jack to relieve the coil spring tension from the rear
lower link.
WAR NIN G:
Do not compress the coil spring when setting the jack.
5. Loosen the rear lower link adjusting bolt and nut connected to
the rear suspension member, using power tool.
6. Remove the rear lower link bolt and nut from the knuckle using
power tool.
7. Slowly lower the suitable jack to release the coil spring tension. Then remove the upper rubber seat, coil
spring, and lower rubber seat from the rear lower link.
LEIA0080E
LEIA0077E
LEIA0009E
LEIA0077E

SC-28
SERVICE DATA AND SPECIFICATIONS (SDS)
Revision: August 20072004 QX56
SERVICE DATA AND SPECIFICATIONS (SDS)PFP:00030
BatteryEKS0079J
StarterEKS0079K
GeneratorEKS0079L
Typ eGr. 27
Capacity (20 HR) minimum 12V - 80AH
Cold cranking current A
(For reference value)710
ApplicationAll models
ManufacturerMitsubishi
M002T85571ZCKD
Ty peReduction gear type
System voltage 12V
No-loadTerminal voltage 11V
Current Less than 145A
Revolution More than 3,300 rpm
Minimum diameter of commutator 31.4 mm (1.236 in)
Minimum length of brush 11.0 mm (0.433 in)
Brush spring tension 26.7 - 36.1 N (2.72 - 3.68 kg, 5.93 - 8.02 lb)
Clearance between pinion front edge and
pinion stopper0.5 - 2.0 mm (0.020 - 0.079 in)
Ty peLR1130-701
Hitachi
Nominal rating12V - 130A
Ground polarityNegative
Minimum revolution under no-load (When 13.5 volts is applied) 1,200 rpm
Hot output current (When 13.5 volts is applied)More than 78A/1,800 rpm
More than 108A/2,500 rpm
More than 130A/5,000 rpm
Regulated output voltage 14.1 - 14.7V @ 25°C
Minimum length of brush 6 mm (0.24 in)
Brush spring pressure 1.0 - 3.432 N (0.102 - 0.3501 kg, 0.22 - 0.7715 lbs)
Slip ring minimum outer diameter 26 mm (1.02 in)
Rotor (Field coil) resistance 2.1 ohms

TF-2Revision: August 20072004 QX56 SWITCH ..................................................................... 62
Diagnostic Procedure ............................................. 62
TRANSFER MOTOR AND TRANSFER MOTOR
RELAY ....................................................................... 64
Diagnostic Procedure ............................................. 64
TRANSFER FLUID TEMPERATURE SENSOR ....... 66
Diagnostic Procedure ............................................. 66
ATP SWITCH, WAIT DETECTION SWITCH AND
NEUTRAL-4LO SWITCH .......................................... 69
Diagnostic Procedure ............................................. 69
CLUTCH PRESSURE SWITCH ................................ 72
Diagnostic Procedure ............................................. 72
LINE PRESSURE SWITCH ....................................... 74
Diagnostic Procedure ............................................. 74
DATA ERASE/DISPLAY ............................................ 76
Diagnostic Procedure ............................................. 76
SHIFT ACTUATOR ................................................... 77
Diagnostic Procedure ............................................. 77
SHIFT ACTUATOR POSITION SWITCH .................. 80
Diagnostic Procedure ............................................. 80
SHIFT ACTUATOR CIRCUIT .................................... 82
Diagnostic Procedure ............................................. 82
TROUBLE DIAGNOSES FOR SYMPTOMS ............. 85
Symptom 1. 4WD Shift Indicator Lamp Does Not
Turn ON (Although the ignition switch is turned ON,
all the 4WD indicator lamps do not turn ON for 1
second) ................................................................... 85
Symptom 2. 4WD Warning Lamp Does Not Turn ON
(Although the ignition switch is turned ON, the 4WD
warning lamp does not turn ON) ............................. 87
Symptom 3. 4WD Shift Indicator Lamp Does Not
Turn OFF (When 4WD shift switch is set from 4H
to 4LO, all the 4WD shift indicator lamps do not turn
off) ........................................................................... 88
Symptom 4. ATP Warning Lamp Does Not Turn ON
(When 4WD shift switch is set from 4H to 4LO with
the A/T selector lever in P position, the ATP warning
lamp does not turn on) ............................................ 89
Symptom 5. 4LO Indicator Lamp Does Not Turn ON
(When 4WD shift switch is set from 4H to 4LO posi-
tion, 4LO indicator lamp does not turn ON) ............ 90
Symptom 6. 4WD Shift Indicator Lamp Does Not
Indicate “LOCK” (When 4WD shift switch is set to
“4H”, 4WD shift indicator lamp does not indicate
“LOCK”) .................................................................. 91
Symptom 7. 4WD Shift Indicator Lamp Repeats
Flickering (4WD Shift Indicator Lamp Keeps Flick-
ering) ...................................................................... 92
Symptom 8. Tight Corner Braking Symptom (Tight
Corner Braking Symptom Occurs-Hydraulic Sys-
tem Failure) ............................................................ 93
Symptom 9. 4WD System Does Not Operate (The
Vehicle Cannot Be Put Into 4WD Mode-Hydraulic
System Failure) ...................................................... 94
Component Inspection ............................................ 95
4WD SHIFT SWITCH .......................................... 95
2-4WD SHIFT SOLENOID VALVE AND TRANS-
FER FLUID TEMPERATURE SENSOR .............. 95
4WD SOLENOID VALVE, CLUTCH PRESSURE SWITCH AND LINE PRESSURE SWITCH .........95
TRANSFER DROPPING RESISTOR ..................96
ATP SWITCH, NEUTRAL-4LO SWITCH AND
WAIT DETECTION SWITCH ...............................96
TRANSFER MOTOR ...........................................96
TRANSFER MOTOR RELAY ...............................97
TRANSFER SHIFT RELAY (HIGH & LOW) .........97
ACTUATOR AND ACTUATOR POSITION
SWITCH ...............................................................97
TRANSFER CONTROL UNIT ...................................98
Removal and Installation .........................................98
REMOVAL ............................................................98
INSTALLATION ....................................................98
FRONT OIL SEAL .....................................................99
Removal and Installation .........................................99
REMOVAL ............................................................99
INSTALLATION .................................................. 100
REAR OIL SEAL ..................................................... 101
Removal and Installation ....................................... 101
REMOVAL .......................................................... 101
INSTALLATION .................................................. 101
SIDE OIL SEAL ....................................................... 103
Removal and Installation ....................................... 103
REMOVAL .......................................................... 103
INSTALLATION .................................................. 103
TRANSFER CONTROL DEVICE ............................ 104
Removal and Installation ....................................... 104
AIR BREATHER HOSE ........................................... 105
Removal and Installation ....................................... 105
TRANSFER MOTOR ............................................... 106
Removal and Installation ....................................... 106
REMOVAL .......................................................... 106
INSTALLATION ..................................................... 106
TRANSFER OIL FILTER ......................................... 107
Removal and Installation ....................................... 107
REMOVAL .......................................................... 107
INSTALLATION .................................................. 107
REMOVAL AND INSTALLATION ............................ 109
Removal ................................................................ 109
Installation ............................................................. 109
OVERHAUL .............................................................110
Transfer Components ...........................................110
REAR CASE ............................................................112
Disassembly ..........................................................112
CENTER CASE .......................................................113
Disassembly ..........................................................113
FRONT DRIVE SHAFT AND DRIVE CHAIN .....115
MAINSHAFT AND CLUTCH DRUM ..................116
CLUTCH PISTON ..............................................118
CONTROL VALVE .............................................119
MAINSHAFT REAR BEARING .......................... 122
MAIN OIL PUMP ................................................ 122
SUB OIL PUMP ................................................. 123
OIL FILTER ........................................................ 124
FRONT CASE .......................................................... 125
Disassembly .......................................................... 125
SHIFT ROD COMPONENTS ............................. 125
PLANETARY CARRIER, SUN GEAR AND
INTERNAL GEAR .............................................. 127

ALL-MODE 4WD SYSTEM
TF-15
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Revision: August 20072004 QX56
Description of Electrical PartsEDS0017R
TRANSFER MOTOR
1. The transfer motor drives the sub-oil pump to provide proper lubrication and oil pressure control when the
vehicle is at standstill, during low-speed operations or is being driven in reverse.
2. The main oil pump is operated by the driving force of the mainshaft. In other words, sufficient oil pressure
buildup does not occur when the vehicle is at standstill or during low-speed operations. While the vehicle
is being driven in reverse, the main oil pump rotates in the reverse direction. Therefore the main oil pump
does not discharge oil pressure. During any of the above vehicle operations, the transfer motor drives the
sub-oil pump to compensate for insufficient oil pressure.
3. The transfer motor operates as follows:
1. The motor relay turns OFF in the 2WD mode.
2. The motor relay operates as described in the table below in modes other than the 2WD mode.
Ta b l e 1
Ta b l e 2
NOTE:
OFF (after 2.5 seconds have elapsed.)
4. 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
1. The wait detection switch releases the “booming” torque produced in the propeller shaft. After the release
of the “booming” torque, the wait detection switch helps provide the 4WD lock gear (clutch drum) shifts. A
difference may occur between the operation (“4LO” to “4H” shift only) of the 4WD shift switch and actual
drive mode. At this point, the wait detection switch senses an actual drive mode.
2. The wait detection switch operates as follows:
4WD lock gear (clutch drum) locked: ON
4WD lock gear (clutch drum) released: OFF
3. The wait detection switch senses an actual drive mode and the 4WD shift indicator lamp indicates the
vehicle drive mode.
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 when the vehicle is set in the
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.
PNP switch “R” position VFF (Vehicle speed) A/T position Motor relay drive command
ON — R ON
OFF0Positions other than the “P” or
“N” positionsON
—“P” or “N” position (See Table
2.)—
0 < VFF ≤ 50 km/h (31 MPH) — ON
50 km/h (31 MPH) < VFF < 55
km/h (34 MPH)—HOLD
55 km/h (34 MPH) ≤ VFF — OFF
A/T position N-4L SW 4WD modeThrottle position
0 - 0.07/8 0.07/8 - 1/8 1/8 - MAX
NOFFLOCK (4H) ON ON ON
Positions other than
the LOCK position
(2WD or AUTO)See NOTE. HOLD ON
ON — See NOTE. HOLD ON
P——See NOTE.HOLDON

TF-16
ALL-MODE 4WD SYSTEM
Revision: August 20072004 QX56
LINE PRESSURE SWITCH
1. 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.
2. The line pressure switch turns ON when line pressure is produced.
3. The line pressure switch senses line pressure abnormalities and turns the 4WD warning lamp ON.

TF-94
TROUBLE DIAGNOSES FOR SYMPTOMS
Revision: August 20072004 QX56
Symptom 9. 4WD System Does Not Operate (The Vehicle Cannot Be Put Into
4WD Mode-Hydraulic System Failure)
EDS0018M
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Select “ECU INPUT SIGNALS” in Data Monitor.
2. Put A/T selector lever in D.
3. Turn 4WD shift switch to 4H and back to 2WD while reading out
ON/OFF status of "CL PRES SW".
Without CONSULT-II
Check voltage between transfer control unit harness connector E143
terminal 34 (BR) and ground.
Refer to TF-55, "
TRANSFER CONTROL UNIT INSPECTION
TABLE" .
OK or NG
OK >> 1. Check transfer fluid level.
2. Disassemble transfer unit and check the following.
–Transfer motor
–Main oil pump assembly
–Sub-oil pump assembly
–Oil strainer
–Control valve assembly
–2-4WD shift solenoid valve
–Oil filter element
–Lip seal
–Strainer O-ring
–Main oil pump drive gear
–Seal ring
–D-ring
–Clutch piston
–Clutch assembly
NG >> GO TO 2.
2. CHECK CLUTCH PRESSURE CIRCUIT
Check clutch pressure switch circuit.
Refer to TF-72, "
Diagnostic Procedure" .
OK or NG
OK >> GO TO 3.
NG >> Check, repair or replace faulty parts.
3. CHECK PROCEDURES FROM THE BEGINNING
Check again.
OK or NG
OK >> Inspection End.
NG >> Recheck each connector pin terminals for damage or loose connection.
WDIA0087E

OVERHAUL
TF-111
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Revision: August 20072004 QX56
46. Snap ring 47. Retaining pin 48. L-H fork
49. 2-4 fork 50. Shift fork spring 51. Fork guide
52. Retainer pin 53. Shift rod
1. Dust cover 2. Oil seal 3. Rear case
4. Air breather 5. Seal ring 6. Main oil pump cover
7. Inner gear 8. Outer gear 9. Main oil pump housing
10. D-ring 11. D-ring 12. Clutch piston
13. Thrust needle bearing race 14. Oil strainer 15. O-ring
16. Snap ring 17. Control valve assembly 18. Lip seal (7 pieces)
19. Washer 20. Filler plug 21. Filler stud
22. O-ring 23. Oil filter 24. ATP switch
25 Neutral-4LO switch 26. Oil pressure check plug 27. Harness bracket
28. Stem bleeder 29. Harness bracket 30. Center case
31. Mainshaft rear bearing 32. C-ring 33. Washer holder
34. Snap ring 35. Sub oil pump housing 36. Outer gear
37. Inner gear 38. Sub oil pump cover 39. O-ring
40. Transfer motor 41. Connector bracket
SDIA2091E

TF-118
CENTER CASE
Revision: August 20072004 QX56
10. Tap mainshaft, using suitable tool to remove it from clutch drum
and clutch hub.
11. Remove needle bearing and spacer from the mainshaft.
12. Remove the snap ring from the clutch hub.
CLUTCH PISTON
1. Remove oil pressure check plug from oil pressure check port.
2. Apply air gradually from oil pressure check port, and remove
clutch piston from center case.
SMT914C
WDIA0101E
SDIA2 115 E
SDIA2 116 E

CENTER CASE
TF-145
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Revision: August 20072004 QX56
4. Remove all the liquid gasket from oil pressure check port and
inside center case. With the new oil pressure check plug
threaded in 1 or 2 pitches, apply specified sealant or equivalent,
to the oil pressure check plug thread of plug, and tighten. Refer
to GI-45, "
Recommended Chemical Products and Sealants" .
NOTE:
Do not reuse oil pressure check plug.
5. Install mainshaft and clutch drum. Refer to TF-145, "
MAIN-
SHAFT AND CLUTCH DRUM" .
MAINSHAFT AND CLUTCH DRUM
1. Apply ATF or petroleum jelly to needle bearing, and install nee-
dle bearing, clutch drum, clutch hub and new snap ring to main-
shaft.
2. Install new snap ring to the clutch hub, using suitable tool.
NOTE:
Do not reuse snap ring.
3. Install new snap ring to clutch hub from clutch hub to mainshaft,
and secure them with snap rings.
NOTE:
Do not reuse snap rings.Oil pressure check plug : 15 N·m (1.5 kg-m, 11 in-lb)
SMT915C
SMT974C
WDIA0101E
SDIA2192E