Hydraulic Flow
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 the line pressure (1). The 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 the torque converter pressure from rising. Under this condition, the 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
The line pressure (1) flows to the manual valve, the modulator valve and the throttle valve. The line pressure (1) becomes to the modulator pressure (6) at the modulator valve, and remains line pressure (4), (18) and (25) at the manual valve. The modulator pressure (6) flows to the right end of the 1-2 and 2-3 shift valves because shift control solenoid valve A is turned ON and B is turned OFF by the TCM, and those valves are moved to the left side. The line pressure (18) flows to the right end of the 3-4 shift valve, and the 3-4 shift valve is moved to the left side. The line pressure (4) becomes the 1st clutch pressure (10). The 1st clutch pressure (10) is applied to the 1st clutch, and the 1st clutch is engaged. The line pressure (4) also becomes the 1st-hold clutch pressure (15) and it flows to the 1st-hold clutch and the 1st-hold accumulator.
Fluid flows by way of:
- Line Pressure (4) -> 1-2 Shift Valve - Line Pressure (5) -> 2-3 Shift Valve - 3rd Clutch Pressure (32) -> 3-4 Shift Valve - 4th Clutch Pressure (42) -> Orifice - 4th Clutch Pressure (41) -> Manual Valve - 1st-hold Clutch Pressure (16) -> Orifice -1st-hold Clutch Pressure (15) -> 1st-hold Clutch.
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
The line pressure (1) flows to the manual valve, the modulator valve and the throttle valve. The line pressure (1) becomes modulator pressure (6) at the modulator valve, and remains line pressure (4) and (25) at the manual valve.
The modulator pressure (6) does not flow to each shift valves because shift control solenoid valves A and B are turned ON by the Transmission Control Module (TCM).
The line pressure (4) becomes the line pressure (5) at the 1-2 shift valve, and the line pressure (5) becomes the 2nd clutch pressure (21) at the 2-3 shift valve. The 2nd clutch pressure (21) changes the 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 line pressure (4) also becomes the 1st clutch pressure (10). The 1st clutch pressure (10) is applied 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
1. 1st Gear
The flow of fluid through the torque converter circuit is the same as in [N] position.
The line pressure (1) flows to the manual valve, the modulator valve and the throttle valve. The line pressure (1) becomes modulator pressure (6) at the modulator valve, and remains line pressure (4) at the manual valve.
The modulator pressure (6) flows to the left end of the 1-2 shift valve and right end of the 3-4 shift valve because shift control solenoid valve A is turned OFF and B is turned ON by the Transmission Control Module (TCM). The 1-2 shift valve is moved to the right side, and the 3-4 shift valve is moved to the left side.
The line pressure (4) becomes the 1st clutch pressure (10). The 1st clutch pressure (10) is applied to the 1st clutch and 1st accumulator; consequently, the vehicle will move as the engine power is transmitted.
In [D3] or [D4] position at 1st gear, the 1st-hold clutch pressure is not applied to the 1st-hold clutch because the manual valve covers the port to leading to the 1st-hold clutch.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
[D3] OR [D4] POSITION
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 Transmission Control Module (TCM). Shift control solenoid valve B remains ON. The 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 2-3 shift valve. The line pressure (5) becomes the 2nd clutch pressure (21) at the 23 shift valve. The 2nd clutch pressure (20) is applied to the 2nd clutch, and the 2nd clutch is engaged.
Fluid flows by way of:
- Line pressure (4) -> 1-2 Shift Valve - Line Pressure (5) -> 2-3 Shift Valve - 2nd Clutch Pressure (21) -> Orifice - 2nd Clutch Pressure (20) -> 2nd Clutch
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.
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 Transmission Control Module (TCM). Shift control solenoid valve A remains ON. The modulator pressure (6B) 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 the modulator pressure (6B). The 2-3 shift valve covers the port to stop line pressure (5) to the 2nd clutch and uncovers to the 3-4 shift valve as this valve is moved to the left side. The line pressure (5) becomes the 3rd clutch pressure. The 3rd clutch pressure (30) is applied to the 3rd clutch, and the 3rd clutch is engaged.
Fluid flows by way of:
-Line Pressure (4) -> 1-2 Shift Valve - Line Pressure (5) -> 2-3 Shift Valve - 3rd Clutch Pressure (32) -> 3-4 Shift Valve - 3rd Clutch Pressure (31) -> Orifice - 3rd Clutch Pressure (30) -> 3rd Clutch
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.
[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 Transmission Control Module (TCM). Shift control solenoid valve B remains OFF. The modulator pressure (6A) flows to the right end of the 3-4 shift valve and the left end of the 1-2 shift valve. The modulator pressure (6A) in the left end of the 1-2 shift valve equals the modulator pressure (6B) in the right end of the 1-2 shift valve, so the 1-2 shift valve remains at left side by the tension of the valve spring.
The 3-4 shift valve is moved to the left side by modulator pressure (6B). 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. The 3rd clutch pressure (32) from the 2-3 shift valve becomes the 4th clutch pressure. The 4th clutch pressure (40) is applied to the 4th clutch, and the 4th clutch is engaged.
Fluid flows by way of:
Line Pressure (4) -> 1-2 Shift Valve - Line Pressure (5) -> 2-3 Shift Valve - 3rd Clutch Pressure (32) -> 3-4 Shift Valve 4th Clutch Pressure (42) -> Orifice - 4th Clutch Pressure (41) -> Manual Valve - 4th Clutch Pressure (40) -> 4th clutch
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.
[R] POSITION
The flow of fluid through the torque converter circuit is the same as in [N] position.
The line pressure (1) becomes the line pressure (3) and flows to the 1-2 shift valve. The line pressure (3) becomes line pressure (3') at the 1-2 shift valve and flows to the servo valve. The servo valve is moved to the right side (Reverse range position) and uncovers the port to allow line pressure (3") to the manual valve. The line pressure (3') from the 1-2 shift valve flows through the servo valve to the manual valve and becomes to the 4th clutch pressure (40). The 4th clutch pressure (40) is applied to the 4th clutch, and the 4th 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 Transmission Control Module (TCM) outputs the 1st signal to shift control solenoid valves A and B; shift control solenoid valve A is turned ON, shift control solenoid valve B is turned OFF. The 1-2 shift valve is moved to the right side and covers the port to stop line pressure (3') to the servo valve. The line pressure (3') is not applied to the servo valve, and the 4th clutch pressure (40) is not applied to the 4th clutch, as a result, power is not transmitted to 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. The line pressure (1) becomes the line pressure (3) and flows to the 1-2 shift valve. The line pressure (3) becomes line pressure (31 at the 1-2 shift valve and flows to the servo valve. The servo valve is moved to the right side (Reverse range position) and uncovers the port to allow line pressure (3") to the manual valve as in [k position. The line pressure (3") from the servo valve is intercepted by the manual valve. However, hydraulic pressure is not supplied to the clutches, and power is not transmitted.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.