2007 INFINITI QX56 transmission

AT-14
< SERVICE INFORMATION >
A/T FLUID
2. Before driving, the ATF level can be checked at ATF tempera-
tures of 30° to 50°C (86° to 122°F) using the “COLD” range on
the ATF level gauge as follows:
a. Park the vehicle on a level surface and set the parking brake.
b. Start the engine and move the selector lever through each gear
position. Shift the selector lever into the “P” position.
c. Check the ATF level with the engine idling.
d. Remove the ATF level gauge and wipe it clean with a lint-free
paper.
CAUTION:
When wiping the ATF from the ATF level gauge, always use
a lint-free paper, not a cloth.
e. Re-insert the ATF level gauge into the charging pipe until the
cap contacts the top of the charging pipe as shown.
CAUTION:
To check ATF level, insert the ATF level gauge until the cap
contacts the top of the charging pipe, with the gauge
reversed from the normal inserted position.
f. Remove the ATF level gauge and note the ATF level. If the ATF
level is at low side of range, add ATF to the transmission
through the charging pipe.
CAUTION:
Do not overfill the transmission with ATF.
g. Install the ATF level gauge and the ATF level gauge bolt.
3. Warm up the engine.
4. Check for any ATF leaks.
5. Drive the vehicle to increase the ATF temperature to 80° C (176° F).
6. Allow the ATF temperature to fall to approximately 65°C (149°F). Use the CONSULT-II to monitor the ATF
temperature as follows:
NOTE:
ATF level will be greatly affected by temperature as shown. Therefore monitor the ATF temperature data
using the CONSULT-II.
a. Connect CONSULT-II to data link connector.
b. Select “MAIN SIGNALS” in “DATA MONITOR” mode for “A/T” with CONSULT-II.
c. Read out the value of “ATF TEMP 1”.
WLIA0014E
ATF level gauge bolt : Refer to AT-223, "Removal and Installation (2WD)",
AT-225, "
Removal and Installation (4WD)".
SCIA1684E
SLIA0016E

A/T FLUID
AT-15
< SERVICE INFORMATION >
D
E
F
G
H
I
J
K
L
MA
B
AT
N
O
P
7. Re-check the ATF level at ATF temperatures of approximately
65°C (149°F) using the “HOT” range on the ATF level gauge as
shown.
CAUTION:
• When wiping the ATF from the ATF level gauge, always
use lint-free paper, not a cloth.
• To check the ATF level, insert the ATF level gauge until the
cap contacts the top of the charging pipe, with the gauge
reversed from the normal inserted position as shown.
8. Check the ATF condition.
• If the ATF is very dark or has some burned smell, there may be an internal problem with the transmis-
sion. Refer to AT-165
. Flush the transmission cooling system after repairing the transmission.
• If the ATF contains frictional material (clutches, bands, etc.), replace the radiator and flush the transmis-
sion cooler lines using cleaning solvent and compressed air after repairing the transmission.
9. Install the ATF level gauge in the ATF charging pipe and install the ATF level gauge bolt.
10. Tighten the level gauge bolt to specification.
A/T Fluid Cooler CleaningINFOID:0000000003532226
Whenever an automatic transmission is repaired, overhauled, or replaced, the A/T fluid cooler mounted in the
radiator must be inspected and cleaned.
Metal debris and friction material, if present, can become trapped in the A/T fluid cooler. This debris can con-
taminate the newly serviced A/T or, in severe cases, can block or restrict the flow of A/T fluid. In either case,
malfunction of the newly serviced A/T may result.
Debris, if present, may build up as A/T fluid enters the cooler inlet. It will be necessary to back flush the cooler
through the cooler outlet in order to flush out any built up debris.
A/T FLUID COOLER CLEANING PROCEDURE
1. Position an oil pan under the automatic transmission's inlet and outlet cooler hoses.
2. Identify the inlet and outlet fluid cooler hoses.
WLIA0014E
SCIA1684E
ATF level gauge
bolt:: Refer to AT-223, "Removal and Installation (2WD)",
AT-225, "
Removal and Installation (4WD)".

AT-16
< SERVICE INFORMATION >
A/T FLUID
3. Disconnect the fluid cooler inlet and outlet rubber hoses from the
steel cooler tubes or bypass valve.
NOTE:
Replace the cooler hoses if rubber material from the hose
remains on the tube fitting.
4. Allow any A/T fluid that remains in the cooler hoses to drain into
the oil pan.
5. Insert the extension adapter hose of a can of Transmission
Cooler Cleaner (Nissan P/N 999MP-AM006) into the cooler out-
let hose.
CAUTION:
• Wear safety glasses and rubber gloves when spraying the
Transmission Cooler Cleaner.
• Spray cooler cleaner only with adequate ventilation.
• Avoid contact with eyes and skin.
• Do not breath vapors or spray mist.
6. Hold the hose and can as high as possible and spray Transmis-
sion Cooler Cleaner in a continuous stream into the cooler outlet
hose until fluid flows out of the cooler inlet hose for 5 seconds.
7. Insert the tip of an air gun into the end of the cooler outlet hose.
8. Wrap a shop rag around the air gun tip and of the cooler outlet
hose.
9. Blow compressed air regulated to 5 - 9 kg/cm
2 (70 - 130 psi) through the cooler outlet hose for 10 seconds
to force out any remaining fluid.
10. Repeat steps 5 through 9 three additional times.
11. Position an oil pan under the banjo bolts that connect the fluid cooler steel lines to the transmission.
12. Remove the banjo bolts.
13. Flush each steel line from the cooler side back toward the transmission by spraying Transmission Cooler
Cleaner in a continuous stream for 5 seconds.
14. Blow compressed air regulated to 5 - 9 kg/cm
2 (70 - 130 psi) through each steel line from the cooler side
back toward the transmission for 10 seconds to force out any remaining fluid.
15. Ensure all debris is removed from the steel cooler lines.
16. Ensure all debris is removed from the banjo bolts and fittings.
17. Perform the A/T fluid cooler diagnosis procedure.
A/T FLUID COOLER DIAGNOSIS PROCEDURE
NOTE:
Insufficient cleaning of the cooler inlet hose exterior may lead to inaccurate debris identification.
1. Position an oil pan under the automatic transmission's inlet and outlet cooler hoses.
2. Clean the exterior and tip of the cooler inlet hose.
SCIA3830E
SCIA3831E
SCIA3832E

A/T FLUID
AT-17
< SERVICE INFORMATION >
D
E
F
G
H
I
J
K
L
MA
B
AT
N
O
P
3. Insert the extension adapter hose of a can of Transmission
Cooler Cleaner (Nissan P/N 999MP-AM006) into the cooler out-
let hose.
CAUTION:
• Wear safety glasses and rubber gloves when spraying the
Transmission Cooler Cleaner.
• Spray cooler cleaner only with adequate ventilation.
• Avoid contact with eyes and skin.
• Do not breath vapors or spray mist.
4. Hold the hose and can as high as possible and spray Transmis-
sion Cooler Cleaner in a continuous stream into the cooler outlet
hose until fluid flows out of the cooler inlet hose for 5 seconds.
5. Tie a common white, basket-type coffee filter to the end of the
cooler inlet hose.
6. Insert the tip of an air gun into the end of the cooler outlet hose.
7. Wrap a shop rag around the air gun tip and end of cooler outlet
hose.
8. Blow compressed air regulated to 5 - 9 kg/cm
2 (70 - 130 psi)
through the cooler outlet hose to force any remaining A/T fluid
into the coffee filter.
9. Remove the coffee filter from the end of the cooler inlet hose.
10. Perform the A/T fluid cooler inspection procedure.
A/T FLUID COOLER INSPECTION PROCEDURE
1. Inspect the coffee filter for debris.
a. If small metal debris less than 1mm (0.040 in) in size or metal
powder is found in the coffee filter, this is normal. If normal
debris is found, the A/T fluid cooler/radiator can be re-used and
the procedure is ended.
SCIA3831E
SCIA3833E
SCIA3834E
SCIA2967E

AT-20
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
Cross-Sectional View (4WD models)
INFOID:0000000003532228
Shift MechanismINFOID:0000000003532229
The automatic transmission uses compact triple planetary 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

AT-22
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
• —Operates
• —Operates during “progressive” 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
D1st
Automatic shift
1⇔2⇔3⇔4⇔5 2nd
3rd
4th
5th
1st
42nd
Automatic shift
3rd1⇔2⇔3⇔4
4th
31st
Automatic shift
1⇔2⇔3⇐4 2nd
3rd
4th
21st
Automatic shift
1⇔2⇐3⇐4 2nd
3rd
4th
11st
Locks (held sta-
tionary in 1st
gear)
1⇐2⇐3⇐4 2nd
3rd
4th Shift position I/C HLR/C D/C R/B FR/B LC/B Fwd/B1st
OWCFwd
OWC3rd
OWCRemarks
SCIA5642E

A/T CONTROL SYSTEM
AT-31
< SERVICE INFORMATION >
D
E
F
G
H
I
J
K
L
MA
B
AT
N
O
P
TCM FunctionINFOID:0000000003532230
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.
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
SCIA1519E

AT-32
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
CONTROL SYSTEM DIAGRAM
CAN CommunicationINFOID:0000000003532231
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,
"CAN Communication System".
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 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
SCIA5624E