Hydraulic Flow

HYDRAULIC FLOW DESCRIPTION





[N] POSITION
As the engine turns, the oil pump also starts to operate. Automatic transmission fluid (ATF) is drawn from (99) and discharged into (1). Then, ATF pressure is controlled by the regulator valve and becomes the line pressure (1). The torque converter inlet pressure (1) enters (94) of torque converter through the orifice and discharges into (90). The torque converter check valve prevents the torque converter pressure from falling~

Under this condition, the hydraulic pressure is not applied to the clutches as the manual valve stops line pressure (1).





[1] POSITION
The line pressure (1) becomes the line pressure (4) at the manual valve and passes to the 1st clutch and 1st accumulator. The line pressure (4) flows through the 1St hold clutch and 1st hold accumulator. The power is transmitted only during deceleration.

FLUID FLOWS BY WAYS OF:
-Line Pressure (4)->1-2 Shift Valve->2-3 Shift Valve->3rd Clutch Pressure (31)->3-4 Shift Valve->3rd Clutch Pressure (31)->3-4 Shift Valve-->4th Clutch Pressure (41)->Manual Valve->4th Clutch Pressure (41)->Manual Valve->1st Hold Clutch Pressure (16)->1st Hold Clutch

The modulator pressure (6) is supplied to the 1-2, 2-3 and 3-4 shift valves. The line pressure (1) also flows to the throttle valve B.





[2] POSITION
The line pressure (1) becomes the line pressure (4) as it passes through the manual valve. It then goes through the line (20) to the 2nd clutch. Also, the line pressure (1) goes to the modulator valve through the filter and becomes the modulator pressure (6). The modulator pressure (6) is supplied to the 1-2, 2-3 and 3-4 shift valves.

The line pressure (1) also flows to the throttle valve B.





[D3] OR [D4] POSITION

1. 1ST SPEED
The flow of fluid through the torque converter is the same as in [N] position.

The line pressure (1) becomes the line pressure (4) and it becomes the 1st clutch pressure (10). The 1st clutch pressure is applied to the 1st clutch and 1st accumulator, consequently the vehicle will move as the engine power is transmitted. The line pressure (1) becomes the modulator pressure (6) by the modulator valve and travels to each shift valve. The 1-2 shift valve is moved to the right side because the shift control solenoid valve A is turned off and B is turned on by the A/T control unit. This valve stops 2nd clutch pressure and the power is not transmitted to the 2nd clutch.

The line pressure (4) also flows to the servo valve and line pressure (1) also flows to throttle valve B.





2. 2ND SPEED
The flow of fluid up to the 1-2 and 2-3 shift valves is the same as in the 1st speed. When the vehicle speed is increased and reaches the prescribed value, the solenoid valve A is turned on by means of the control unit. As a result, the 1-2 shift valve is moved to the left and uncovers the port leading to the 2nd clutch; the 2nd clutch is engaged.

THE FLUID FLOWS BY WAY OF:
-Line pressure (4)->1 -2 Shift Valve-->2-3 Shift Valve-2nd Clutch Pressure (21)->Orifice-2nd Clutch Pressure-(20)->2nd Clutch.

The hydraulic pressure also flows to the 1st clutch. However no power is transmitted because of the one-way clutch.





3. 3RD SPEED
The flow of fluid up to the 1-2, 2-3 and 3-4 shift valves is the same as in the 2nd speed. As the speed of the car reaches the prescribed value, the shift control solenoid valve B is turned off (shift control valve A remains on). The 2-3 shift valve is then moved to the left, uncovering the oil port leading to the 3rd clutch. Since the 3-4 shift valve is moved to the right to cover the oil port to the 4th clutch, the 3rd clutch is turned on.

FLUID FLOWS BY WAY OF:
-Line Pressure (4)->1-2 Shift Valve-->2-3 Shift Valve-3rd Clutch Pressure (31)->3-4 Shift Valve (not controlled)
-3rd Clutch Pressure (3O)->3rd Clutch

The hydraulic pressure also flows to the 1St clutch However no power is transmitted because of the one-way clutch as in the 2nd speed.





[D4] POSITION

4TH SPEED
The flow of fluid up to the 1-2, 2-3 and 3-4 shift valves is the same as in the 3rd speed. When the speed of the car reaches the prescribed value, the shift control solenoid valve A is turned off (shift control solenoid valve B remains off). As this takes place, 3-4 shift valve is moved to the left and uncovers the oil port leading to the 4th clutch. Since the 1-2 and 2-3 shift valves are kept on the left side, the fluid flows through the 4th clutch; the power is transmitted through the 4th clutch.

FLUID FLOWS BY WAYS OF:
-Line Pressure (4)->1-2 Shift Valve-->2-3 Shift Valve-3rd Clutch Pressure (31)->3-4 Shift Valve-3rd Clutch Pressure (31)->3-4 Shift Valve-4th Clutch pressure (41)->Manual Valve->4th Clutch Pressure (4O)->4th Clutch.

The hydraulic pressure also flows to the 1st clutch. However no power is transmitted because of the one-way clutch as in 2nd and 3rd speed.





[R] POSITION
The flow of fluid through the torque converter circuit is the same as in the [N]. The fluid (1) from the oil pump flows through the manual valve and becomes the line pressure (3). It then flows through the 1-2 shift valve to the servo valve (3), causing the shift fork shaft to be moved in the reverse direction

Under this condition, the shift control solenoid valve A is turned on whereas the valve B is turned off as in 3rd. As a result, the 1-2 shift valve is also moved to the left. The fluid (3)' will flow through the servo valve and manual valve to the 4th clutch; power is transmitted through the 4th clutch.

REVERSE INHIBITOR CONTROL
When the [R] position is selected while the vehicle is moving forward at a speed over 10 km/h (6 mph), the control unit outputs 1st signal (A: OFF, B: ON), the 1-2 shift valve is moved to the right. The line pressure (3) is intercepted by the 1-2 shift valve, consequently the power is not transmitted as the 4th clutch and servo valve are not operated.





[P] POSITION
The flow of fluid through the torque converter is the same in [N] position. The line pressure (1) is intercepted by the manual valve, and is not supplied to the clutches. The power is not transmitted.