Hydraulic Flow
N POSITION
As the engine turns, the Automatic Transmission Fluid (ATF) pump also starts to operate. 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) changes to the modulator pressure (6) at the modulator valve and to the line pressure (4), (18) and (25) at the manual valve. The modulator pressure (6) flows to the left end of the 1-2 shift valve because shift control solenoid valve A is turned OFF, and the 1-2 shift valve is moved to the right side. The line pressure (4) changes to the 1st clutch pressure (10) at the 1-2 shift valve and the orifice. The 1st clutch pressure (10) flows to the 1st clutch. The line pressure (18) changes to the 1st-hold clutch pressure (15) at the 1-2 shift valve then the 1st-hold clutch pressure (15) flows to 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) changes to the modulator pressure (6) at the modulator valve and to the line pressure (4), (18) and (25) at the manual valve. But the modulator pressure (6) does not flow to each shift valve because shift control solenoid valves A and B are turned ON by the TCM. The line pressure (4) passes through the 1-2 shift valve and changes to the line pressure (5). The line pressure (5) flows to the 2-3 shift valve and changes to the 2nd clutch pressure (20) at the 2-3 shift valve. The 2nd clutch pressure (20) is applied to the 2nd clutch. The line pressure (4) passes through the orifice and changes the 1st clutch pressure. The 1st clutch pressure (10) 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 OR D3 POSITION
1. 1st Gear: The flow of fluid through the torque converter circuit is 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) changes to the modulator pressure (6) at the modulator valve and to the line pressure (4) and (25) at the manual valve. The modulator pressure (6) flows to the left end of the 1-2 shim valve and to the right end of the 3-4 shift valve because shift control solenoid valve A is turned OFF and B is turned ON by the 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) changes to the 1st clutch pressure (10) at the 1-2 shift valve and the orifice. The 1st clutch pressure is applied to the 1st clutch and the 1st accumulator; consequently, the vehicle will move as the engine power is transmitted. In D4 or D3 position at 1st gear, the 1st-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 TCM. The modulator pressure (SHA) in the 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) changes to the 2nd clutch pressure (20) at the 2-3 shift valve. The 2nd clutch pressure (20) is applied to the 2nd clutch, and the 2nd clutch is engaged. Fluid flows by way of:
a. Line Pressure (4)
b. 1-2 Shift Valve - Line Pressure (5)
c. 2-3 Shift Valve - 2nd Clutch Pressure (20)
d. 2nd Clutch
NOTE: Hydraulic pressure also flows to the 1st clutch. However, no power is transmitted because of the one-way clutch. 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 TCM. Shift control solenoid valve A remains ON. The modulator pressure (6) flows to the right end 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 (SHA). 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 since 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:
a. Line Pressure (4)
b. 1-2 Shift Valve - Line pressure (5)
c. 2-3 Shift Valve - 3rd Clutch Pressure (31)
d. 3-4 Shift Valve - 3rd Clutch Pressure (30)
e. 3rd Clutch
NOTE: Hydraulic pressure also flows to the 1st clutch. However, no power is transmitted because of the one-way clutch as in the 2nd gear. When used, "left" or "right" indicates direction on the hydraulic circuit.
4. 4th gear (D4 Position): As the speed of the vehicle reaches the prescribed value, shift control solenoid valve A is turned OFF by means of the TOM. Shift control solenoid valve B remains OFF. The modulator pressure (6) flows to the right end of the 3-4 shift valve and the left end of the 1-2 shift valve. The modulator pressure (SHA) in the left end of the 1-2 shift valve equals the modulator pressure (SHA) in the right end of the 1-2 shift valve, 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 the modulator pressure (SHA). 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 (31 ) 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:
a. Line Pressure (4)
b. 1-2 Shift Valve - Line Pressure (5)
c. 2-3 Shift Valve - 3rd Clutch Pressure (31)
d. 3-4 Shift Valve - 4th Clutch Pressure (41)
e. Manual Valve - 4th Clutch Pressure (40)
f. 4th Clutch
NOTE: Hydraulic pressure also flows to the 1st clutch. However, no power is transmitted because of the one-way clutch as in the 2nd and 3rd gear. 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 JO position. The line pressure (1) changes to the line pressure (3) and flows to the 1-2 shift valve. The line pressure (3) changes to the 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 changes 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 TOM 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 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 E1 position. The line pressure (1) changes to the line pressure (3) and flows to the 1-2 shift valve. The line pressure (3) changes to the 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 as in R 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 the power is not transmitted.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.