Automatic Transmission/Transaxle: Description and Operation

DESCRIPTION





A5SR1/ 2





MAJOR COMPONENTS AND THEIR FUNCTIONS






COMPONENTS





OPERATION





OPERATING PRINCIPLES OF EACH RANGE
1. N range
Since the forward and reverse brakes are released, driving force of input shaft is not transmitted to output shaft.
2. P range
A. Since the forward and reverse brakes are released, as those in the N range, driving force of input shaft is not transmitted to output shaft.
B. Parking pawl that is linked with select lever parking gear meshes with and fastens output shaft mechanically.
3. D, M2, M3, M4, M5 range 1st speed
A. Fastens the front brake.
B. The front brake and the forward one-way clutch regulate reverse rotation of the mid sun gear.
C. The 1st one-way clutch regulates reverse rotation of the rear sun gear.
D. The 3rd one-way clutch regulates reverse rotation of the front sun gear.





* POWER FLOW
Input shaft->Front internal gear->Front carrier->Rear internal gear->Rear carrier->Middle internal gear->Middle carrier->Output shaft
4. D, M3, M4, M5 range ratio 2nd
A. Fasten the front brake.
B. The front brake and the forward one-way clutch regulate reverse rotation of the mid sun gear.
C. The 3rd one-way clutch regulates reverse rotation of the front sun gear.




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

* POWER FLOW
Input shaft->Front internal gear->Front carrier->Rear internal gear->Rear carrier->Rear carrier->Middle internal gear->Middle carrier->Output shaft
5. D, M3, M4, M5 range 3rd speed
A. Fastens the front brake.
B. The 3rd one-way clutch regulates reverse rotation of the front sun gear.




C. The high & low reverse clutch is coupled and the middle and rear sun gears are connected.

* POWER FLOW
Input shaft->Front internal gear->Front carrier->Rear internal gear->Rear carrier->Rear carrier->Middle internal gear->Middle carrier->Output shaft
6. D, M4, M5 range 4th speed
A. The front brake is released and sun gear turns freely forward.
B. The input clutch is coupled and the front and middle internal gears are connected.




C. Driving force is conveyed to the front internal gear, the middle internal gear, and the rear carrier and the three planetary gears rotate forward as a unit.

* POWER FLOW
Input shaft->Front internal gear->Front carrier->Rear internal gear->Rear carrier->Middle internal carrier->Middle carrier->Output shaft
7. D, M5 range 5th speed
A. The front brake fastens the front sun gear.
B. The direct clutch is released and the rear carrier and rear sun gear are disconnected.




* POWER FLOW
Input shaft->Front internal->Front carrier->Rear internal input shaft->Middle internal->Rear carrier->Rear sun gear->Middle sun carrier->Middle carrier->Output shaft
8. R range
A. The front brake fastens the front sun gear.
B. The high & low reverse clutch is coupled and the middle and rear sun gears are connected.
C. The reverse brake fastens the rear carrier.




* POWER FLOW
Input shaft->Front internal->Front carrier->Rear internal->Rear sun gear->Middle sun gear->Middle carrier->Output shaft

CONTROL SYSTEM DIAGRAM




MAIN COMMUNICATION SIGNAL





LINE PRESSURE CONTROL






LINE PRESSURE SYSTEM DIAGRAM





Line pressure control based on line pressure characteristic pattern of A/T control unit (TCM)
- A/T control unit (TCM) has stored in memory a number of patterns for the optimum line pressure characteristics according to driving conditions.
- In order to obtain the most appropriate line pressure characteristic to meet the current driving state, the TCM controls the line pressure solenoid current valve and thus controls the line pressure.
- Normal line pressure control.
Each clutch is adjusted to the necessary pressure to match the engine drive force.




- Back-up control (Engine brake)
Line pressure according to speed is set during shift down by select operation while driving.




- During shift change
Set to line pressure that is necessary for shift change. Therefore, line pressure characteristic is set according to input torque and shift types.




- At low fluid temperature
When the A/T fluid temperature drops below the prescribed temperature, in order to speed up the action of each friction element, the line pressure is set higher than the normal line pressure characteristic.




Shift control






SHIFT CONTROL SYSTEM DIAGRAM









Lock-up control






LOCK-UP OPERATING CONDITION TABLE










LOCK-UP CONTROL SYSTEM DIAGRAM









Engine brake control






ENGINE BRAKE CONTROL SYSTEM DIAGRAM










CONTROL VALVE
Control valve functions






SUB ROM unit
1. Installing location: The valve body upper part
2. Function: To obtain A/T fluid pressure stability by compensating for solenoid&valve body unit fluid pressure differential.
3. Principle: Install additional ROM onto valve body of automatic transmission and input fluid pressure differential of solenoid &valve body so that TCM reads the input data to perform fluid pressure compensation.








4. Maintenance
(1) When replacing with a new TCM in the vehicle
A. TCM automatically reads SUB ROM DATA during I.G ON. At this time, shift range valve is off for about 2.5 second.
(2) When replacing A/T (regardless of new or old ones) in the vehicle
A. Must erase SUB ROM DATA stored in TCM.
B. With the ignition ON (engine OFF), maintain 50% throttle opening in R range while using the TCU SUB ROM RESET mode on the scan tool.
C. TCM reads SUB ROM DATA from a new A/T upon I.G ON again after I.G OFF.
(3) Moving TCM from vehicle A to another vehicle B
A. Perform the same way as in 2) above.