INFINITI QX4 2005 Factory Owners Manual

AT-20
A/T CONTROL SYSTEM
Revision: October 20052005 QX56
POWER TRANSMISSION
“N” Position
Since both the forward brake and the reverse brake are released, torque from the input shaft drive is not trans-
mitted to the output shaft.
“P” Position

The same as for the “N” position, both the forward brake and the reverse brake are released, so torque
from the input shaft drive is not transmitted to the output shaft.

The parking pawl linked with the select lever meshes with the parking gear and fastens the output shaft
mechanically.
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1. Front brake 2. Input clutch 3. 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 gear 12. Input shaft
13. Mid internal gear 14. Front internal gear 15. Rear carrier
16. Rear sun gear 17. Mid sun gear 18. Front carrier
19. Mid carrier 20. Rear internal gear 21. Output shaft
22. Parking gear 23. Parking pawl
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A/T CONTROL SYSTEM
AT-21
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Revision: October 20052005 QX56
“D”, “4”, “3”, “2” Positions 1st Gear

The forward brake and the forward one-way clutch regulate reverse rotation of the mid sun gear.

The 1st one-way clutch regulates reverse rotation of the rear sun gear.

The 3rd one-way clutch regulates reverse rotation of the front sun gear.

During deceleration, the mid sun gear turns forward, so the forward one-way clutch idles and the engine
brake is not activated.
1. Front brake 2. Input clutch 3. 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 gear 12. Input shaft
13. Mid internal gear 14. Front internal gear 15. Rear carrier
16. Rear sun gear 17. Mid sun gear 18. Front carrier
19. Mid carrier 20. Rear internal gear 21. Output shaft
22. Parking gear 23. Parking pawl
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AT-22
A/T CONTROL SYSTEM
Revision: October 20052005 QX56
“1 ” Position 1st Gear

The front brake fastens the front sun gear.

The forward brake and the forward one-way clutch regulate reverse rotation of the mid sun gear.

High and low reverse clutch connects the rear sun gear and the mid sun gear.

The low coast brake fastens the mid sun gear.

During deceleration, the low coast brake regulates forward rotation of the mid sun gear and the engine
brake functions.
1. Front brake 2. Input clutch 3. 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 gear 12. Input shaft
13. Mid internal gear 14. Front internal gear 15. Rear carrier
16. Rear sun gear 17. Mid sun gear 18. Front carrier
19. Mid carrier 20. Rear internal gear 21. Output shaft
22. Parking gear 23. Parking pawl
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A/T CONTROL SYSTEM
AT-23
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Revision: October 20052005 QX56
“D”, “4”, “3” Positions 2nd Gear

The forward brake and the forward one-way clutch regulate reverse rotation of the mid sun gear.

The 3rd one-way clutch regulates reverse rotation of the front sun gear.

The direct clutch is coupled and the rear carrier and rear sun gear are connected.

During deceleration, the mid sun gear turns forward, so the forward one-way clutch idles and engine
brake is not activated.
1. Front brake 2. Input clutch 3. 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 gear 12. Input shaft
13. Mid internal gear 14. Front internal gear 15. Rear carrier
16. Rear sun gear 17. Mid sun gear 18. Front carrier
19. Mid carrier 20. Rear internal gear 21. Output shaft
22. Parking gear 23. Parking pawl
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AT-24
A/T CONTROL SYSTEM
Revision: October 20052005 QX56
“2”, “1” Positions 2nd Gear

The front brake fastens the front sun gear.

The forward brake and the forward one-way clutch regulate reverse rotation of the mid sun gear.

The direct clutch is coupled, and the rear carrier and rear sun gear are connected.

The low coast brake fastens the mid sun gear.

During deceleration, the low coast brake regulates forward rotation of the mid sun gear and the engine
brake functions.
1. Front brake 2. Input clutch 3. 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 gear 12. Input shaft
13. Mid internal gear 14. Front internal gear 15. Rear carrier
16. Rear sun gear 17. Mid sun gear 18. Front carrier
19. Mid carrier 20. Rear internal gear 21. Output shaft
22. Parking gear 23. Parking pawl
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A/T CONTROL SYSTEM
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Revision: October 20052005 QX56
“D”, “4”, “3” Positions 3rd Gear

The front brake fastens the front sun gear.

The direct clutch is coupled, and the rear carrier and rear sun gear are connected.

The high and low reverse clutch is coupled and the mid sun gear and rear sun gear are connected.
1. Front brake 2. Input clutch 3. 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 gear 12. Input shaft
13. Mid internal gear 14. Front internal gear 15. Rear carrier
16. Rear sun gear 17. Mid sun gear 18. Front carrier
19. Mid carrier 20. Rear internal gear 21. Output shaft
22. Parking gear 23. Parking pawl
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AT-26
A/T CONTROL SYSTEM
Revision: October 20052005 QX56
“D”, “4” Positions 4th Gear

The direct clutch is coupled, and the rear carrier and rear sun gear are connected.

The high and low reverse clutch is coupled and the mid sun gear and rear sun gear are connected.

The input clutch is coupled and the front internal gear and mid internal gear are connected.

The drive power is conveyed to the front internal gear, mid internal gear, and rear carrier and the three
planetary gears rotate forward as one unit.
1. Front brake 2. Input clutch 3. 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 gear 12. Input shaft
13. Mid internal gear 14. Front internal gear 15. Rear carrier
16. Rear sun gear 17. Mid sun gear 18. Front carrier
19. Mid carrier 20. Rear internal gear 21. Output shaft
22. Parking gear 23. Parking pawl
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A/T CONTROL SYSTEM
AT-27
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Revision: October 20052005 QX56
“D” Position 5th Gear

The front brake fastens the front sun gear.

The input clutch is coupled and the front internal gear and mid internal gear are connected.

The high and low reverse clutch is coupled and the mid sun gear and rear sun gear are connected.
1. Front brake 2. Input clutch 3. 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 gear 12. Input shaft
13. Mid internal gear 14. Front internal gear 15. Rear carrier
16. Rear sun gear 17. Mid sun gear 18. Front carrier
19. Mid carrier 20. Rear internal gear 21. Output shaft
22. Parking gear 23. Parking pawl
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AT-28
A/T CONTROL SYSTEM
Revision: October 20052005 QX56
“R” Position

The front brake fastens the front sun gear.

The high and low reverse clutch is coupled, and the mid sun gear and rear sun gear are connected.

The reverse brake fastens the rear carrier.
1. Front brake 2. Input clutch 3. 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 gear 12. Input shaft
13. Mid internal gear 14. Front internal gear 15. Rear carrier
16. Rear sun gear 17. Mid sun gear 18. Front carrier
19. Mid carrier 20. Rear internal gear 21. Output shaft
22. Parking gear 23. Parking pawl
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A/T CONTROL SYSTEM
AT-29
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Revision: October 20052005 QX56
TCM FunctionECS00CDW
The function of the TCM is to:

Receive input signals sent from various switches and sensors.

Determine required line pressure, shifting point, 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 various sensors or signals. It always
controls the optimum shift position and reduces shifting and lock-up shocks.
CONTROL SYSTEM DIAGRAM
SENSORS (or SIGNALS)


TCM


ACTUATORS
PNP switch
Accelerator pedal position sensor
Closed throttle position signal
Wide open throttle position signal
Engine speed signal
A/T fluid temperature sensor
Revolution sensor
Vehicle speed signal
Stop lamp switch signal
Turbine revolution sensor
1st position switch signal
4th position switch signal
ATF pressure switch signal
Tow mode switch signalShift control
Line pressure control
Lock-up control
Engine brake control
Timing control
Fail-safe control
Self-diagnosis
CONSULT-II communication line
Duet-EA control
CAN systemInput clutch solenoid valve
Direct clutch solenoid valve
Front brake solenoid valve
High and low reverse clutch
solenoid valve
Low coast brake solenoid valve
Torque converter clutch solenoid
valve
Line pressure solenoid valve
A/T CHECK indicator lamp
Sta rte r re lay
Back-up lamp relay
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