2001 INFINITI QX4 service

TRANSFER
SECTION
TF
CONTENTS
PRECAUTIONS...............................................................3
Supplemental Restraint System (SRS)²AIR
BAG²and²SEAT BELT PRE-TENSIONER²...............3
Precautions ..................................................................3
Service Notice..............................................................4
Wiring Diagrams and Trouble Diagnosis .....................4
PREPARATION...............................................................5
Special Service Tools ..................................................5
Commercial Service Tools ...........................................9
ALL-MODE 4WD SYSTEM...........................................10
Cross-sectional View .................................................10
Control System .......................................................... 11
ALL-MODE 4WD TRANSFER BASIC CONTROL........12
HYDRAULIC CONTROL CIRCUITS...........................12
OUTLINE................................................................12
CONTROL SYSTEM DIAGRAM................................13
INDICATIONS OF 4WD WARNING LAMP..................13
Location of Electrical Parts ........................................14
Description of Electrical Parts ...................................15
TRANSFER MOTOR................................................15
WAIT DETECTION SWITCH.....................................15
2-4WD SHIFT SOLENOID VALVE.............................16
LINE PRESSURE SWITCH.......................................16
Circuit Diagram for Quick Pinpoint Check.................17
Wiring Diagram - TF -................................................18
ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION...............................................................27
Trouble Diagnosis without CONSULT-II ....................27
DESCRIPTION........................................................27
SELF-DIAGNOSTIC PROCEDURE............................28
INDICATIONS OF 4WD WARNING LAMP..................29
Trouble Diagnosis with CONSULT-II .........................30
SELF-DIAGNOSIS...................................................30
SELF-DIAGNOSTIC ITEMS......................................31
DATA MONITOR......................................................33
DATA MONITOR ITEMS...........................................34
REFERENCE VALUE IN DATA MONITOR MODE......36
WORK SUPPORT....................................................38
CLUTCH FORCE RELEASE LIMIT ADJUSTMENT.....39
TROUBLE DIAGNOSIS - INTRODUCTION..................41Introduction ................................................................41
DESCRIPTION........................................................41
DIAGNOSTIC WORKSHEET.....................................41
Work Flow ..................................................................43
HOW TO PERFORM TROUBLE DIAGNOSES FOR
QUICK AND ACCURATE REPAIR
.............................43
TROUBLE DIAGNOSIS - BASIC INSPECTION...........44
Listen to Customer Complaints .................................44
Transfer Fluid Check .................................................44
Road Test...................................................................44
PREPARATION FOR ROAD TEST............................44
1. CHECK BEFORE ENGINE IS STARTED...............45
2. CHECK AT IDLE..................................................47
3. CRUISE TEST.....................................................51
TROUBLE DIAGNOSIS - GENERAL
DESCRIPTION...............................................................54
Transfer Control Unit Terminals and Reference
Value ..........................................................................54
REMOVAL AND INSTALLATION OF TRANSFER
CONTROL UNIT
......................................................54
INSPECTION OF TRANSFER CONTROL UNIT..........54
TRANSFER CONTROL UNIT INSPECTION TABLE....55
VEHICLE SPEED SENSOR (FRONT
REVOLUTION SENSOR)..............................................61
Diagnostic Procedure ................................................61
4WD SOLENOID VALVE...............................................64
Diagnostic Procedure ................................................64
2-4WD SHIFT SOLENOID VALVE AND 4WD
SHIFT SWITCH..............................................................66
Diagnostic Procedure ................................................66
TRANSFER MOTOR AND TRANSFER MOTOR
RELAY...........................................................................70
Diagnostic Procedure ................................................70
TRANSFER FLUID TEMPERATURE SENSOR............73
Diagnostic Procedure ................................................73
ATP SWITCH, WAIT DETECTION SWITCH AND
NEUTRAL-4LO SWITCH...............................................76
Diagnostic Procedure ................................................76
CLUTCH PRESSURE SWITCH....................................80
Diagnostic Procedure ................................................80
GI
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX

LINE PRESSURE SWITCH...........................................83
Diagnostic Procedure ................................................83
ABS OPERATION SIGNAL...........................................86
Diagnostic Procedure ................................................86
DATA ERASE/DISPLAY...............................................88
Diagnostic Procedure ................................................88
SHIFT ACTUATOR........................................................89
Diagnostic Procedure ................................................89
SHIFT ACTUATOR POSITION SWITCH......................92
Diagnostic Procedure ................................................92
SHIFT ACTUATOR CIRCUIT........................................94
Diagnostic Procedure ................................................94
TROUBLE DIAGNOSES FOR SYMPTOMS.................98
Symptom 1. 4WD Shift Indicator Lamp Does Not
Turn ON .....................................................................98
Symptom 2. 4WD Warning Lamp Does Not Turn
ON............................................................................100
Symptom 3. 4WD Shift Indicator Lamp Does Not
Turn OFF .................................................................102
Symptom 4. ATP Warning Lamp Does Not Turn
ON............................................................................102
Symptom 5. 4LO Indicator Lamp Does Not Turn
ON............................................................................104
Symptom 6. 4WD Shift Indicator Lamp Does Not
Indicate²4H²............................................................106
Symptom 7. 4WD Shift Indicator Lamp Repeats
Flickering..................................................................107
Symptom 8. Tight Corner Braking Symptom...........108
Symptom 9. 4WD System Does Not Operate.........109
COMPONENT INSPECTION....................................... 111
4WD Shift Switch ..................................................... 111
2-4WD Shift Solenoid Valve and Transfer Fluid
Temperature Sensor ................................................ 111
4WD Solenoid Valve, Clutch Pressure Switch
and Line Pressure Switch........................................ 111
Front Revolution Sensor .......................................... 112
Transfer Dropping Resistor...................................... 112
ATP Switch, Neutral-4LO Switch and Wait
Detection Switch ...................................................... 112
Transfer Motor ......................................................... 113
Transfer Motor Relay ............................................... 113
Transfer Sub-harness .............................................. 113
FRONT REVOLUTION SENSOR SUB-HARNESS
CONNECTOR
........................................................ 113
TRANSFER SWITCH ASSEMBLY SUB-HARNESS
CONNECTOR
........................................................ 114
TRANSFER TERMINAL CORD ASSEMBLY SUB-
HARNESS CONNECTOR
....................................... 114
Transfer Shift Relay (High & low) ............................ 114
Actuator & Actuator Position Switch ........................ 115
ACTUATOR........................................................... 115
ACTUATOR POSITION SWITCH............................ 115
ON-VEHICLE SERVICE.............................................. 116
Replacing Oil Seal ................................................... 116
FRONT CASE OIL SEAL........................................ 116
SHIFT SHAFT OIL SEAL........................................ 117
REAR OIL SEAL.................................................... 117
Transfer Motor ......................................................... 117
REMOVAL............................................................. 117
INSTALLATION...................................................... 117
Transfer Oil Filter ..................................................... 118
REMOVAL............................................................. 118
INSTALLATION...................................................... 118
REMOVAL AND INSTALLATION............................... 119
Removal ................................................................... 119
Installation ................................................................ 119
OVERHAUL.................................................................120
Transfer Gear Control ..............................................120
Transfer Components ..............................................121
DISASSEMBLY............................................................123
Rear Case................................................................123
DISASSEMBLY......................................................123
Center Case.............................................................123
DISASSEMBLY......................................................123
Front Case ...............................................................133
DISASSEMBLY......................................................133
REPAIR FOR COMPONENT PARTS.........................137
Front Case ...............................................................137
INSPECTION.........................................................137
Center Case.............................................................138
INSPECTION.........................................................138
ASSEMBLY..................................................................141
Front Case ...............................................................141
ASSEMBLY...........................................................141
Center Case.............................................................145
ASSEMBLY...........................................................145
Final Assembly.........................................................153
SERVICE DATA AND SPECIFICATIONS (SDS).......157
General Specifications .............................................157
Inner Gear and Outer Gear .....................................157
SUB-OIL PUMP.....................................................157
MAIN OIL PUMP....................................................157
Control Valve ...........................................................157
VALVE..................................................................157
SPRING................................................................157
Clutch .......................................................................158
DRIVE PLATE.......................................................158
DRIVEN PLATE.....................................................158
RETURN SPRING..................................................158
RETAINING PLATE................................................158
Seal Ring (Mainshaft side) ......................................159
Bearing Race (Thrust needle bearing side) ............159
Snap Ring (Sun gear side) ......................................159
CONTENTS(Cont'd)
TF-2

Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NBTF0001The Supplemental Restraint System such as ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº used along with
a seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain types of
collision. The SRS system composition which is available to INFINITI QX4 is as follows:
IFor a frontal collision
The Supplemental Restraint System consists of driver air bag module (located in the center of the steer-
ing wheel), front passenger air bag module (located on the instrument panel on passenger side), seat belt
pre-tensioners, a diagnosis sensor unit, warning lamp, wiring harness and spiral cable.
IFor a side collision
The Supplemental Restraint System consists of side air bag module (located in the outer side of front seat),
satellite sensor, diagnosis sensor unit (one of components of air bags for a frontal collision), wiring harness,
warning lamp (one of components of air bags for a frontal collision).
Information necessary to service the system safely is included in theRSsection of this Service Manual.
WARNING:
ITo avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance must be performed
by an authorized INFINITI dealer.
IImproper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the RS section.
IDo not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. Spiral cable and wiring harnesses covered with yellow insulation tape either just
before the harness connectors or for the complete harness are related to the SRS.
SEF289H
PrecautionsNBTF0092IBefore connecting or disconnecting the Transfer control
unit harness connector, turn ignition switch OFF and dis-
connect negative battery terminal. Failure to do so may
damage the Transfer control unit. Because battery voltage
is applied to Transfer control unit even if ignition switch
is turned off.
SEF291H
IWhen connecting or disconnecting pin connectors into or
from Transfer control unit, take care not to damage pin
terminals (bend or break).
Make sure that there are not any bends or breaks on
Transfer control unit pin terminal, when connecting pin
connectors.
GI
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
PRECAUTIONS
Supplemental Restraint System (SRS) ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº
TF-3

MEF040DB
IBefore replacing Transfer control unit, perform Transfer
control unit input/output signal inspection and make sure
whether Transfer control unit functions properly or not.
(See page TF-55.)
Service NoticeNBTF00021) Before proceeding with disassembly, thoroughly clean the outside of the all-mode 4WD transfer. It is
important to prevent the internal parts from becoming contaminated by dirt or other foreign matter.
2) Disassembly should be done in a clean work area.
3) Use lint-free cloth or towels for wiping parts clean. Common shop rags can leave fibers that could inter-
fere with the operation of the all-mode 4WD transfer.
4) Place disassembled parts in order for easier and proper assembly.
5) All parts should be carefully cleaned with a general purpose, non-flammable solvent before inspection or
reassembly.
6) Gaskets, seals and O-rings should be replaced any time the all-mode 4WD transfer is disassembled.
7) It is very important to perform functional tests whenever they are indicated.
8) The valve body contains precision parts and requires extreme care when parts are removed and serviced.
Place removed parts in a parts rack in order to replace them in correct positions and sequences. Care will
also prevent springs and small parts from becoming scattered or lost.
9) Properly installed valves, sleeves, plugs, etc. will slide along bores in valve body under their own weight.
10) Before assembly, apply a coat of recommended ATF to all parts. Apply petroleum jelly to protect O-rings
and seals, and to hold bearings and washers in place during assembly. Do not use grease.
11) Extreme care should be taken to avoid damage to O-rings, seals and gaskets when assembling.
12) After overhaul, refill the transfer with new ATF.
13) When the all-mode 4WD transfer drain plug is removed, only some of the fluid is drained. Old all-mode
4WD transfer fluid will remain in torque converter and ATF cooling system. Always follow the procedures,
MA-22, ªChanging All-mode 4WD Transfer Fluidº.
Wiring Diagrams and Trouble DiagnosisNBTF0003When you read wiring diagrams, refer to the following:
IGI-11, ªHOW TO READ WIRING DIAGRAMSº
IEL-9, ªPOWER SUPPLY ROUTINGº
When you perform trouble diagnosis, refer to the following:
IGI-35, ªHOW TO FOLLOW TEST GROUPS IN TROUBLE DIAGNOSISº
IGI-24, ªHOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENTº
PRECAUTIONS
Precautions (Cont'd)
TF-4

Special Service ToolsNBTF0004The actual shapes of Kent-Moore tools may differ from those of special service tools illustrated here.
Tool number
(Kent-Moore No.)
Tool nameDescription
KV38108300
(J44195)
Companion flange
wrench
NT771
Removing companion flange nut
Installing companion flange nut
KV40100621
(J26091)
Drift
NT086
Installing front drive shaft bearing
a: 76 mm (2.99 in) dia.
b: 69 mm (2.72 in) dia.
ST30032000
(Ð)
Base
NT660
Installing front drive shaft bearing
a: 38 mm (1.50 in) dia.
b: 80 mm (3.15 in) dia.
ST30021000
(Ð)
Puller
NT411
Removing front drive shaft bearing
a: 110 mm (4.33 in) dia.
b: 68 mm (2.68 in) dia.
ST33052000
(Ð)
Adapter
NT431
Removing front drive shaft bearing
a: 28 mm (1.10 in) dia.
b: 22 mm (0.87 in) dia.
ST35271000
(J26091)
Drift
NT115
Installing rear oil seal
Removing and installing press flange snap ring
a: 72 mm (2.83 in) dia.
b: 63 mm (2.48 in) dia.
GI
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
PREPARATION
Special Service Tools
TF-5

Tool number
(Kent-Moore No.)
Tool nameDescription
ST27863000
(Ð)
Support ring
NT661
Removing and installing press flange snap ring
a: 74.5 mm (2.933 in) dia.
b: 62.5 mm (2.461 in) dia.
KV40104710
(Ð)
Support ring
NT661
Removing and installing press flange snap ring
a: 76.3 mm (3.004 in) dia.
b: 67.9 mm (2.673 in) dia.
ST35291000
(Ð)
Remover
NT662
Removing mainshaft rear bearing
a: 40 mm (1.57 in) dia.
b: 29.5 mm (1.161 in) dia.
c: 22.5 mm (0.886 in) dia.
ST30090010
(Ð)
Remover
NT663
Removing mainshaft rear bearing
a: 165 mm (6.50 in)
b: 25 mm (0.98 in) dia.
c: M16 x P2.0
KV38100500
(Ð)
Drift
NT115
Installing front drive shaft oil seal
a: 80 mm (3.15 in) dia.
b: 60 mm (2.36 in) dia.
KV40100621
(J25273)
Drift
NT104
Installing mainshaft rear bearing
a: 76 mm (2.99 in) dia.
b: 69 mm (2.72 in) dia.
PREPARATION
Special Service Tools (Cont'd)
TF-6

Tool number
(Kent-Moore No.)
Tool nameDescription
KV32101100
(Ð)
Pin punch
NT410
Removing and installing L-H fork, 2-4 fork
a: 6 mm (0.24 in) dia.
ST3306S001
(J22888-D)
Differential side bearing
puller set
1: ST33051001
(Ð)
Puller
2: ST33061000
(J8107-2)
Adapter
NT072
Installing mainshaft rear bearing
Removing sun gear assembly
a: 28.5 mm (1.122 in) dia.
b: 38 mm (1.50 in) dia.
ST30911000
(Ð)
Puller
NT664
Installing mainshaft and planetary carrier assembly
a: 98 mm (3.86 in) dia.
b: 40.5 mm (1.594 in) dia.
KV381054S0
(Ð)
Outer race puller
NT665
Removing rear oil seal
KV40105230
(Ð)
Adapter
NT666
Installing planetary carrier assembly
a: 92 mm (3.62 in) dia.
b: 86 mm (3.39 in) dia.
c: 12 mm (0.47 in)
KV40105310
(Ð)
Support ring
NT661
Installing planetary carrier assembly
a: 89.1 mm (3.508 in) dia.
b: 80.7 mm (3.177 in) dia.
GI
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
PREPARATION
Special Service Tools (Cont'd)
TF-7

Tool number
(Kent-Moore No.)
Tool nameDescription
KV40105500
(Ð)
Support
NT667
Installing planetary carrier assembly
a: 69 mm (2.72 in) dia.
b: 52 mm (2.05 in) dia.
c: 120 mm (4.72 in) dia.
KV38100200
(Ð)
Drift
NT673
Installing transfer cover oil seal
a: 65 mm (2.56 in) dia.
b: 49 mm (1.93 in) dia.
KV31103300
(Ð)
Drift
NT668
Removing and installing press flange snap ring
a: 76.3 mm (3.004 in) dia.
b: 130 mm (5.12 in)
KV31103400
(Ð)
Clutch piston attachment
1 Shaft-drift
2 Guide-cylinder
NT669
Installing clutch piston
a: 88.5 mm (3.484 in) dia.
b: 158 mm (6.22 in) dia.
ST33290001
(J25810-A)
Puller
NT414
Removing center case oil seal
Removing rear oil seal
a: 250 mm (9.84 in)
b: 160 mm (6.30 in)
ST33051001
(J22888)
Puller
NT824
Removing companion flange
a: 135 mm (5.31 in)
b: 100 mm (3.94 in)
c: 170 mm (6.69 in)
PREPARATION
Special Service Tools (Cont'd)
TF-8