TM-4
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ................................................................
173
Precaution Necessary for Steering Wheel Rota-
tion After Battery Disconnect .................................
173
Precaution for On Board Diagnosis (OBD) System
of A/T and Engine ..................................................
174
Precaution .............................................................174
Service Notice or Precaution .................................175
PREPARATION ..........................................176
PREPARATION .............................................. .176
Special Service Tool ............................................ ..176
Commercial Service Tool ......................................177
ON-VEHICLE MAINTENANCE ..................178
A/T FLUID ....................................................... .178
Checking the A/T Fluid (ATF) .............................. ..178
Changing the A/T Fluid (ATF) ................................180
A/T FLUID COOLER ........................................182
A/T Fluid Cooler Cleaning ................................... ..182
Inspection ..............................................................184
STALL TEST ....................................................185
Inspection and Judgment .................................... ..185
LINE PRESSURE TEST ..................................187
Inspection and Judgment .................................... ..187
ROAD TEST .....................................................189
Description ........................................................... ..189
Check Before Engine Is Started ............................189
Check At Idle ....................................................... ..189
Cruise Test - Part 1 ...............................................190
Cruise Test - Part 2 ...............................................192
Cruise Test - Part 3 ...............................................193
Vehicle Speed When Shifting Gears .....................193
Vehicle Speed When Performing and Releasing
Complete Lock-up .................................................
193
A/T POSITION .................................................194
Checking of A/T Position ..................................... ..194
Adjustment of A/T Position ....................................194
ON-VEHICLE REPAIR ...............................195
SHIFT CONTROL SYSTEM ........................... .195
A/T Shift Selector Removal and Installation ..........195
Checking of A/T Position ..................................... ..196
Adjustment of A/T Position ....................................196
AIR BREATHER HOSE ...................................197
Removal and Installation ..................................... ..197
OIL PAN ...........................................................199
Oil Pan ................................................................. .199
CONTROL VALVE WITH TCM ........................201
Control Valve with TCM and A/T Fluid Tempera-
ture Sensor 2 ....................................................... .
201
REAR OIL SEAL ..............................................213
Rear Oil Seal ........................................................ .213
REMOVAL AND INSTALLATION .............214
TRANSMISSION ASSEMBLY ........................ ..214
Removal and Installation (2WD) .......................... .214
Removal and Installation (4WD) ...........................216
DISASSEMBLY AND ASSEMBLY ...........220
OVERHAUL ......................................................220
Component .......................................................... .220
Oil Channel ...........................................................227
Location of Adjusting Shims, Needle Bearings,
Thrust Washers and Snap Rings ......................... .
229
DISASSEMBLY .............................................. ..232
Disassembly ......................................................... .232
REPAIR FOR COMPONENT PARTS ..............250
Oil Pump .............................................................. .250
Front Sun Gear, 3rd One-Way Clutch ...................252
Front Carrier, Input Clutch, Rear Internal Gear .....254
Mid Sun Gear, Rear Sun Gear, High and Low Re-
verse Clutch Hub ................................................. .
259
High and Low Reverse Clutch ..............................264
Direct Clutch .........................................................266
ASSEMBLY .................................................... ..269
Assembly (1) ........................................................ .269
Adjustment ............................................................282
Assembly (2) .........................................................284
SERVICE DATA AND SPECIFICATIONS
(SDS) ........ .................................................
291
SERVICE DATA AND SPECIFICATIONS
(SDS) .............................................................. ..
291
General Specification ........................................... .291
Vehicle Speed at Which Gear Shifting Occurs .....291
Vehicle Speed at Which Lock-up Occurs/Releas-
es ......................................................................... .
291
Stall Speed ............................................................292
Line Pressure ........................................................292
A/T Fluid Temperature Sensor ..............................292
Input Speed Sensor ..............................................292
Output Speed Sensor ...........................................292
Reverse Brake ......................................................292
Total End Play .......................................................292
Torque Converter ..................................................293
Revision: March 2010 2008 QX56
DIAGNOSIS AND REPAIR WORKFLOWTM-5
< BASIC INSPECTION >
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BASIC INSPECTION
DIAGNOSIS AND REPAIR WORKFLOW
Work FlowINFOID:0000000001603985
INTRODUCTION
The TCM receives a signal from the output speed sensor, accelera-
tor pedal position sensor (throttle position sensor) or transmission
range switch. Then provides shift c ontrol or lock-up control via A/T
solenoid valves.
The TCM also communicates with the ECM by means of a signal
sent from sensing elements used wit h the OBD-related parts of the
A/T system for malfunction-diagnostic purposes. The TCM is capa-
ble of diagnosing malfunctioning parts while the ECM can store mal-
functions in its memory.
Input and output signals must always be correct and stable in the
operation of the A/T system. T he A/T system must be in good oper-
ating condition and be free of valve seizure, solenoid valve malfunc-
tion, etc.
It is much more difficult to diagnose an error that occurs intermit-
tently rather than continuously. Most intermittent errors are caused
by poor electric connections or impr oper wiring. In this case, careful
checking of suspected circuits may help prevent the replacement of
good parts.
A visual check only may not find t he cause of the errors. A road test
with CONSULT-III (or GST) or a circuit tester connected should be
performed. Follow the “DETAILED FLOW”.
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a driveability complaint. The cus-
tomer can supply good information about such errors, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A “Diagnostic work sheet” as shown on
the example (Refer to TM-6
) should be used.
Start your diagnosis by looking for “conventional” errors first. This will
help troubleshoot driveability errors on an electronically controlled
engine vehicle.
Also check related Service bulletins.
DETAILED FLOW
1.COLLECT THE INFORMATION FROM THE CUSTOMER
Get the detailed information from the customer about the symptom (the condition and the environment when
the incident/malfunction occurred) us ing diagnosis worksheet. Refer to TM-6, "
Diagnostic Work Sheet".
>> GO TO 2.
2.CHECK SYMPTOM 1
Check the following items based on the in formation obtained from the customer.
• Fail-safe. Refer to TM-114, "
Fail-Safe".
• A/T fluid inspection. Refer to TM-178, "
Checking the A/T Fluid (ATF)".
• Stall test. Refer to TM-185, "
Inspection and Judgment".
• Line pressure test. Refer to TM-187, "
Inspection and Judgment".
SAT631IB
SAT632I
SEF234G
Revision: March 2010 2008 QX56
A/T CONTROL SYSTEMTM-9
< FUNCTION DIAGNOSIS >
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Cross-Sectional View (4WD models)INFOID:0000000001603988
Shift MechanismINFOID:0000000001603989
The automatic transmission uses compact triple planet ary gear systems to improve power-transmission effi-
ciency, simplify construction and reduce weight.
It also employs an optimum shift control and super wide gear ratios. They improve starting performance and
acceleration during medium and high-speed operation.
CONSTRUCTION
1. Front planetary gear 2. Mid planetary gear 3. Rear planetary gear
4. Direct clutch 5. High and low reverse clutch 6. Reverse brake
7. Drum support 8. Forward brake 9. Low coast brake
10. Input shaft 11. Torque converter 12. Oil pump
13. Front brake 14. 3rd one-way clutch 15. Input clutch
16. 1st one-way clutch 17. Control valve with TCM 18. Forward one-way clutch
19. Adapter case 20. Output shaft
SCIA5268E
Revision: March 2010 2008 QX56
A/T CONTROL SYSTEMTM-11
< FUNCTION DIAGNOSIS >
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• —Operates
• —Operates during “pro gressive” acceleration.
• —Operates and effects power transmission while coasting.
• —Line pressure is applied but does not affect power transmission.
• —Operates under conditions shown in HLR/C Operating Condition
• —Operates under conditions shown in LC/B Operating Condition. Delay control is applied during D (4,3,2,1) ⇒N shift.
POWER TRANSMISSION
“N” Position
NNEUTRAL POSI-
TION
D 1st
Automatic shift
1 ⇔ 2⇔ 3⇔ 4⇔ 5
2nd
3rd
4th
5th1st
4 2nd
Automatic shift
3rd 1
⇔ 2⇔ 3⇔ 4
4th
3 1st
Automatic shift1⇔ 2⇔ 3⇐4
2nd
3rd 4th
2 1st
Automatic shift1⇔ 2⇐3 ⇐4
2nd
3rd
4th
1 1st
Locks (held sta-tionary in 1st gear)
1 ⇐ 2⇐3 ⇐4
2nd
3rd4th
Shift position I/C HLR/C D/C R/B FR/B LC/B Fwd/B
1st
OWC Fwd
OWC 3rd
OWC Remarks
SCIA5642E
Revision: March 2010
2008 QX56
TM-20
< FUNCTION DIAGNOSIS >
A/T CONTROL SYSTEM
TCM Function
INFOID:0000000001603990
The function of the TCM is to:
• Receive input signals sent from various switches and sensors.
• Determine required line pressure, shifting poi nt, lock-up operation, and engine brake operation.
• Send required output signals to the respective solenoids.
CONTROL SYSTEM OUTLINE
The automatic transmission senses vehicle operating conditions through vari ous sensors or signals. It always
controls the optimum shift position and reduces shifting and lock-up shocks.
1. Front brake 2. Input clutch3. Direct clutch
4. High and low reverse clutch 5. Reverse brake 6. Forward brake
7. Low coast brake 8. 1st one-way clutch 9. Forward one-way clutch
10. 3rd one-way clutch 11. Front sun gear12. Input shaft
13. Mid internal gear 14. Front internal gear15. Rear carrier
16. Rear sun gear 17. Mid sun gear18. Front carrier
19. Mid carrier 20. Rear internal gear21. Output shaft
22. Parking gear 23. Parking pawl
SCIA1519E
Revision: March 2010 2008 QX56
A/T CONTROL SYSTEMTM-21
< FUNCTION DIAGNOSIS >
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CONTROL SYSTEM DIAGRAM
CAN CommunicationINFOID:0000000001603991
SYSTEM DESCRIPTION
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only. For details, refer to LAN-4,
"System Description".
SENSORS (or SIGNALS)
⇒TCM
⇒ACTUATORS
Transmission range switch
Accelerator pedal position sensor
Closed throttle position signal
Wide open throttle position signal
Engine speed signal
A/T fluid temperature sensor
Output speed sensor
Vehicle speed signal
Stop lamp switch signal
Input speed sensor
1st position switch signal
4th position switch signal
ATF pressure switch 2 signal
Tow mode switch signal Shift control
Line pressure control
Lock-up control
Engine brake control
Timing control
Fail-safe control
Self-diagnosis
CONSULT-III co
mmunication
line
Duet-EA control
CAN system Input clutch solenoid valve
Direct clutch solenoid valve
Front brake solenoid valve
High and low reverse clutch sole-
noid valve
Low coast brake solenoid valve
Torque converter clutch solenoid
valve
Line pressure solenoid valve
A/T CHECK indicator lamp
Starter relay
Back-up lamp relay
JSDIA1315GB
Revision: March 2010
2008 QX56
TM-22
< FUNCTION DIAGNOSIS >
A/T CONTROL SYSTEM
Input/Output Signal of TCM
INFOID:0000000001603992
*1: Spare for output speed sensor
*2: Spare for accelerator pedal position signal
*3: If these input and output signals are different, the TCM triggers the fail-safe function.
*4: CAN comm unications
Line Pressure ControlINFOID:0000000001603993
• When an input torque signal equivalent to the engine drive force is sent from the ECM to the TCM, the TCM
controls the line pressure solenoid.
Control item Line
pressure control Ve h i c l e
speed
control Shift
control Lock-up
control Engine
brake
control Fail-safe
function (*3) Self-diag-
nostics
function
Input Accelerator pedal position signal
(*4)XXXXXXX
Output speed sensor A/T X X X X X X
Output speed sensor MTR
(*1) (*4)XXXX X
Closed throttle position signal
(*4)(*2) X (*2) X X (*2) XX
Wide open throttle position signal
(*4)(*2) X (*2) X (*2) XX
Input speed sensor 1 X XXX X
Input speed sensor 2
(for 4th speed only) X
XXX X
Engine speed signals
(*4)XX
Transmission range switch XXXXXXX
A/T fluid temperature sensors 1, 2 X X X X X X X
ASCD Operation signal
(*4)XXXX
Overdrive cancel sig-
nal
(*4)XX X
TCM power supply voltage signal X X X X X X
Out-
put Direct clutch solenoid
X XX X
Input clutch solenoid X XX X
High and low reverse clutch sole-
noid XX
XX
Front brake solenoid X XX X
Low coast brake solenoid (ATF
pressure switch 2) XX
XXX
Line pressure solenoid XXXXXXX
TCC solenoid XX X
Starter relay XX
Revision: March 2010 2008 QX56
A/T CONTROL SYSTEMTM-25
< FUNCTION DIAGNOSIS >
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*1: Full phase real-time feedback control monitors move ment of gear ratio at gear change, and controls oil
pressure at real-time to achieve the best gear ratio.
Lock-up ControlINFOID:0000000001603995
The torque converter clutch piston in the torque conv erter is engaged to eliminate torque converter slip to
increase power transmission efficiency.
The torque converter clutch control valve operation is controlled by the torque conver ter clutch solenoid valve,
which is controlled by a signal from TCM, and the torque converter clutch control valve engages or releases
the torque converter clutch piston.
Lock-up Operation Condition Table
TORQUE CONVERTER CLUTCH CONTROL VALVE CONTROL
Lock-up Control System Diagram
Lock-up Released
• In the lock-up released state, the torque converter clutch control valve is set into the unlocked state by the
torque converter clutch solenoid and the lock-up apply pressure is drained.
In this way, the torque converter clutch piston is not coupled.
Lock-up Applied
• In the lock-up applied state, the torque converter clutch control valve is set into the locked state by the
torque converter clutch solenoid and lock-up apply pressure is generated.
In this way, the torque converter clutch piston is pressed and coupled.
SMOOTH LOCK-UP CONTROL
PCIA0013E
Select lever D position4 position 3 position 2 position
G ear p osit io n 54432
Lock-up ×– ×××
Slip lock-up ××–––
PCIA0014E
Revision: March 2010 2008 QX56