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AT-12
PREPARATION
Revision: October 20052005 QX56
Commercial Service ToolsECS00CDP
Tool nameDescription
Power toolLoosening bolts and nuts
DriftInstalling manual shaft seals
a: 22 mm (0.87 in) dia.
DriftInstalling rear oil seal (4WD models)
a: 64 mm (2.52 in) dia.
PBIC0190E
NT083
SCIA5338E
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A/T FLUID
AT-13
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A/T FLUIDPFP:KLE40
Changing A/T FluidECS00CDQ
Refer to MA-24, "Changing A/T Fluid" .
Checking A/T FluidECS0 0CD R
Refer to MA-22, "Checking A/T Fluid" .
A/T Fluid Cooler CleaningECS00CDS
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.
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.
SCIA3830E
SCIA3831E
SCIA3832E
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AT-14
A/T FLUID
Revision: October 20052005 QX56
9. Blow compressed air regulated to 5 - 9 kg/cm2 (70 - 130 psi) through the cooler outlet hose for 10 sec-
onds 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 AT-13, "
A/T FLUID COOLER CLEANING 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.
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 AT - 1 5 , "
A/T FLUID COOLER INSPECTION PROCE-
DURE" .
SCIA3831E
SCIA3833E
SCIA3834E
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A/T FLUID
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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.
b. If one or more pieces of debris are found that are over 1mm
(0.040 in) in size and/or peeled clutch facing material is found in
the coffee filter, the fluid cooler is not serviceable. The A/T fluid
cooler/radiator must be replaced and the inspection procedure is
ended. Refer to CO-12, "
RADIATOR" .
A/T FLUID COOLER FINAL INSPECTION
After performing all procedures, ensure that all remaining oil is cleaned from all components.
SCIA2967E
SCIA5257E
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AT-16
A/T CONTROL SYSTEM
Revision: October 20052005 QX56
A/T CONTROL SYSTEMPFP:31036
Cross-Sectional View (2WD models)ECS00CDT
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. Rear extension 20. Output shaft
SCIA5267E
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A/T CONTROL SYSTEM
AT-17
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Cross-Sectional View (4WD models)ECS0 0CD U
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
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A/T CONTROL SYSTEM
AT-31
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Line Pressure ControlECS00CDZ
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.
This line pressure solenoid controls the pressure regulator valve as the signal pressure and adjusts the
pressure of the operating oil discharged from the oil pump to the line pressure most appropriate to the
driving state.
LINE PRESSURE CONTROL IS BASED ON THE TCM LINE PRESSURE CHARACTERISTIC
PATTERN
The TCM has stored in memory a number of patterns for the optimum line pressure characteristic for the
driving state.
In order to obtain the most appropriate line pressure characteristic to meet the current driving state, the
TCM controls the line pressure solenoid current value and thus controls the line pressure.
Normal Control
Each clutch is adjusted to the necessary pressure to match the
engine drive force.
Back-up Control (Engine Brake)
When the select operation is performed during driving and the trans-
mission is shifted down, the line pressure is set according to the
vehicle speed.
PCIA0007E
PCIA0008E
PCIA0009E
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AT-32
A/T CONTROL SYSTEM
Revision: October 20052005 QX56
During Shift Change
The necessary and adequate line pressure for shift change is set.
For this reason, line pressure pattern setting corresponds to input
torque and gearshift selection. Also, line pressure characteristic is
set according to engine speed, during engine brake operation.
At Low Fluid Temperature
When the A/T fluid temperature drops below the prescribed tempera-
ture, in order to speed up the action of each friction element, the line
pressure is set higher than the normal line pressure characteristic.
Shift ControlECS00CE0
The clutch pressure control solenoid is controlled by the signals from the switches and sensors. Thus, the
clutch pressure is adjusted to be appropriate to the engine load state and vehicle driving state. It becomes
possible to finely control the clutch hydraulic pressure with high precision and a smoother shift change charac-
teristic is attained.
SHIFT CHANGE
The clutch is controlled with the optimum timing and oil pressure by the engine speed, engine torque informa-
tion, etc.
PCIA0010E
PCIA0 011 E
PCIA0012E