Automatic Transmission/Transaxle
HYDRAULIC FLOW
[N]Position
As the engine turns, the ATF pump also starts to operate. Automatic transmission fluid (ATF) is drawn from (99) and discharged into (1). Then, ATF flowing from the ATF pump becomes line pressure (1). Line pressure (1) is regulated by the regulator valve. The torque converter inlet pressure (92) enters (94) of the torque converter through the lock-up shift valve and discharges into (90). The torque converter check valve prevents torque converter pressure from rising. Under this condition, hydraulic pressure is not applied to the clutches as the manual valve stops line pressure (1).
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
[1] Position
Line pressure (1) flows to the manual valve, the modulator valve, the line pressure control valve, and the throttle valve. Line pressure (1) becomes modulator pressure (6) at the modulator valve, line pressure (4) and (7), and 1st-hold clutch pressure (70) at the manual valve. Modulator pressure (6) flows to the 1-2 shift valve, the 2-3 shift valve and the 3-4 shift valve because the shift control solenoid valve A is turned OFF and B is turned ON by the PCM, and the 1-2 shift valve is moved to the right side. Line pressure (4) becomes 1st clutch pressure (10) at the 1-2 shift valve. The 1st clutch pressure (10) is applied to the 1st clutch, and the 1st clutch is engaged. Line pressure (7) becomes 1st-hold clutch pressure (70) at the 1-2 shift valve. The 1st-hold clutch pressure (70) is applied to the 1st-hold clutch, and the 1st-hold clutch is engaged.
Power is transmitted only during deceleration through the 1st-hold clutch.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
[2]Position
Line pressure (1) flows to the manual valve, the modulator valve, the line pressure control valve, and the throttle valve. Line pressure (1) becomes modulator pressure (6) at the modulator valve, line pressure (4), and 1st-hold clutch pressure (70) at the manual valve. Modulator pressure (6) does not flow to each shift valve because shift control solenoid valves A and B are turned ON by the PCM. Line pressure (4) passes through the 1-2 shift valve and the 2-3 shift valve, then changes to 2nd clutch pressure (20) at the orifice. The 2nd clutch pressure (20) is applied to the 2nd clutch, and the 2nd clutch is engaged. The 1st-hold clutch pressure (70) passes through the 1-2 shift valve, then goes to the 1st-hold clutch. The 1sthold clutch is engaged. Power is transmitted only during deceleration through the 1st-hold clutch.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
[D4] for [D3] Position
1. 1st Gear
The flow of fluid through the torque converter circuit is the same as in [N] position. Line pressure (1) flows the manual valve, the modulator valve, the line pressure control valve, and the throttle valve. Line pressure (1) becomes modulator pressure (6) at the modulator valve, and line pressure (4) at the manual valve. Modulator pressure (6) flows to the left ends of the 1-2 shift valve and the 3-4 shift valve because shift control solenoid valve A is turned OFF and B is turned ON by the PCM. The 1-2 shift valve is moved to the right side, and uncovers the port to allow the 1st clutch pressure (10) to the 1st clutch. The 1st clutch pressure (10) is applied to the 1st clutch, and the vehicle will move as the engine power is transmitted. In [D4] or [D3] position, 11st-hold clutch pressure is not applied to the 1st-hold clutch because the manual valve covers the port leading to the 1st-hold clutch.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
2. 2nd Gear
As the speed of the vehicle reaches the prescribed value, shift control solenoid valve A is turned ON by means of the PCM. Shift control solenoid valve B remains ON. Modulator pressure (6A) in the left end of the 1-2 shift valve is released by turning shift control solenoid valve A ON. The 1-2 shift valve is moved to the left side and uncovers the port to allow line pressure (5) to the 2nd clutch. Line pressure (5) becomes 2nd clutch pressure (20) at the orifice. The 2nd clutch pressure (20) is applied to the 2nd clutch, and the 2nd clutch is engaged. Hydraulic pressure also flows to the 1st clutch. However, no power is transmitted because of the one-way clutch.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
[D3] or [D4] Position
3. 3rd Gear
As the speed of the vehicle reaches the prescribed value, shift control solenoid valve B is turned OFF by means of the PCM. Shift control solenoid valve A remains ON. Modulator pressure (613) flows to the right ends of the 1-2 shift valve and the 2-3 shift valve. The 2-3 shift valve is moved to the left side by modulator pressure (613). The 2-3 shift valve uncovers the port to allow line pressure (5) to the 3-4 shift valve as this valve is moved to the left side. Line pressure (5') becomes 3rd clutch pressure at the 3-4 shift valve. The 3rd clutch pressure (30) is applied to the 3rd clutch, and the 3rd clutch is engaged.
Hydraulic pressure also flows to the 1st clutch and 2nd clutch. However, no power is transmitted because of the oneway clutches.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
[D4] Position
4. 4th Gear
As the speed of the vehicle reaches the prescribed value, shift control solenoid valve A is turned OFF by means of the PCM. Shift control solenoid valve B remains OFF. Modulator pressure (6A) flows to the right end of the 3-4 shift valve and the left end of the 1-2 shift valve. Modulator pressure (6A) in the left end of the 1-2 shift valve equals modulator pressure (6B) in the right end of the 1-2 shift valve, so the 1-2 shift valve remains in the left side by the tension of the valve spring. The 3-4 shift valve is moved to the left side by modulator pressure (613). The 3-4 shift valve covers the port leading to the 3rd clutch and uncovers to the 4th clutch as this valve is moved to the left side. Line pressure (5') from the 2-3 shift valve becomes 4th clutch pressure (40) at the 3-4 shift valve. The 4th clutch pressure (40) is applied to the 4th clutch, and the 4th clutch is engaged.
Hydraulic pressure also flows to the 1st clutch and 2nd clutch. However, no power is transmitted because of the oneway clutches.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
[R] Position
The flow of fluid through the torque converter circuit is the same as in [N] position.
Line pressure (1) becomes the modulator pressure (6) at the modulator valve, and line pressure (3) at the manual valve.
Modulator pressure (6) flows to the right ends of the 1-2 shift valve and 2-3 shift valve because shift control solenoid valve A is turned ON and B is turned OFF by the PCM, and those valves are moved to the left side.
Line pressure (3) flows to the 1-2 shift valve, and it becomes reverse clutch pressure (50). Reverse clutch pressure (50) is applied to the reverse clutch, and the reverse clutch is engaged.
Reverse Inhibitor Control
When the [R] position is selected while the vehicle is moving forward at speeds over 6 mph (10 km/h), the PCM outputs the 1st signal to shift control solenoid valves A and B; shift control solenoid valve A is turned OFF, shift control solenoid valve B is turned ON. The 1-2 shift valve is moved to the right side and covers the port to stop line pressure (3) to the reverse clutch. Line pressure (3) is not applied to the reverse clutch, and reverse clutch pressure (50) is not applied to the reverse clutch, as a result, power is not transmitted in the reverse direction.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
[P] Position
The flow of fluid through the torque converter circuit is the same as in [N] position. Line pressure (1) is intercepted by the manual valve. Hydraulic pressure is not supplied to the clutches, and power is not transmitted.