Part 2
Hydraulic ControlsThe valve body includes the main valve body, the regulator valve body, the secondary valve body, and the accumulator body. The ATF pump is driven by splines on the end of the torque converter which is attached to the engine. Fluid flows through the regulator valve to maintain specified pressure through the main valve body to the manual valve, directing pressure to each of the clutches. Shift solenoid valves A, B, and C, and the torque converter clutch solenoid valve are mounted on the accumulator body. A/T clutch pressure control solenoid valves A, B, and C are mounted on the transmission housing.
Main Valve Body
The main valve body contains the manual valve, the modulator valve, the torque converter check valve, shift valve A, shift valve B, shift valve D, shift valve E, CPC valve C, the cooler check valve, the relief valve, the lock-up shift valve, the lock-up timing valve, the lubrication control valve, the lubrication check valve, and the ATF pump gears. The primary function of the main valve body is to switch fluid pressure on and off to control hydraulic pressure going to the hydraulic control system.
Regulator Valve Body
The regulator valve body is located on the main valve body. The regulator valve body contains the regulator valve, the lock-up control valve, the servo valve, and the 3rd accumulator.
Regulator Valve
The regulator valve maintains constant hydraulic pressure from the ATF pump to the hydraulic control system, while also furnishing fluid to the lubricating system and the torque converter. Fluid from the ATF pump flows through B and B'. Fluid entering from B flows through the valve orifice to the A cavity. This pressure of the A cavity pushes the regulator valve to the spring side, and this movement of the regulator valve uncovers the fluid port to the torque converter and the relief valve. The fluid flows out to the torque converter and the relief valve, and the regulator valve returns under spring force. According to the level of the hydraulic pressure through B, the position of the regulator valve changes, and the amount of fluid from B' through the torque converter changes. This operation is continued, maintaining the line pressure.
Increases in hydraulic pressure according to torque are performed by the regulator valve using stator torque reaction. The stator shaft is splined to the stator in the torque converter, and its arm end contacts the regulator spring cap. When the vehicle is accelerating or climbing (torque converter range), stator torque reaction acts on the stator shaft, and the stator arm pushes the regulator spring cap in the direction of the arrow in proportion to the reaction. The stator reaction spring compresses, and the regulator valve moves to increase the line pressure which is regulated by the regulator valve. The line pressure reaches its maximum when the stator torque reaction reaches its maximum.
Secondary Valve Body
The secondary valve body is on the main valve body. The secondary valve body contains shift valve C, CPC valve A, CPC valve B, the reverse CPC valve, the servo control valve, the kick-down valve, and the kick-down short valve.
Accumulator Body
The accumulator body is on the secondary valve body, and contains the 1st, 1st-hold, 2nd, 4th, and 5th accumulators. The 3rd accumulator is in the regulator valve body.
Hydraulic Flow
Distribution of Hydraulic Pressure
As the engine turns, the ATF pump starts to operate. Automatic transmission fluid (ATF) is drawn through the ATF strainer (filter) and discharged into the hydraulic circuit. Then, ATF flowing from the ATF pump becomes line pressure that is regulated by the regulator valve. Torque converter pressure from the regulator valve enters the torque converter through the lock-up shift valve and it is discharged from the torque converter. The torque converter check valve prevents torque converter pressure from rising.
The PCM controls the shift solenoid valves ON and OFF, and the shift solenoid valves control shift solenoid pressure to the shift valves. Applying shift solenoid pressure to the shift valves moves the position of the shift valve, and switches the port of hydraulic pressure. The PCM also controls A/T clutch pressure control solenoid valves A and B. A/T clutch pressure control solenoid valves A and B regulate the A/T clutch pressure and apply it CPC valves A and B. When shifting gears, the clutch is engaged by pressure from the CPC pressure mode. The PCM controls one of the shift solenoid valves to move the position of the shift valve. This movement switches the port of the CPC and line pressure. Line pressure is then applied to the clutch, and the CPC pressure is intercepted. Engaging the clutch with line pressure happens when shifting is completed.
Hydraulic pressure at the ports
N Position
The PCM controls the shift solenoid valves. The conditions of the shift solenoid valves and positions of the shift valve are as follows:
^ Shift solenoid valve A is turned OFF, and shift valve A moves to the left side.
^ Shift solenoid valve B is turned ON, and shift valve B stays on the right side.
^ Shift solenoid valve C is turned OFF, and shift valve C stays on the left side.
Line pressure (1) passes through the manual valve and becomes line pressure (25). Line pressure (25) stops at shift valve D. Line pressure (1) also flows to the modulator valve and becomes modulator pressure (6). Modulator pressure (6) flows to the shift solenoid valves, A/T clutch pressure control solenoid valves A and B, and A/T clutch pressure control solenoid valve C. Under this condition, the hydraulic pressure is not applied to the clutches.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
D Position: 1st gear shifting from the N position
Shift solenoid valves remain the same as in the N position when shifting to the D position from the N position. The manual valve moves to D position and switches the port of line pressure (4) leading to shift valve C and CPC valve B. Line pressure (4) flows to the 1st clutch via shift valve C. Line pressure (1) becomes CPC C pressure (4C) at CPC valve C, then goes to the 1st accumulator back side. Line pressure (4) also becomes CPC B pressure (4B) at CPC B valve. CPC B pressure goes to the 3rd clutch, via shift valves C, B, and A, and the 3rd clutch is engaged. The 1st clutch is engaged gently when shifting to the D position from the N position.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
D Position: Driving in 1st gear
PCM turns shift solenoid valves A and C ON, and shift solenoid valve B remains ON. SH A pressure (SA) in the right side of shift valves A and E is released, and shift valves A and E are mov6d to the right side. SH C pressure (SC) in the right side of shift valve C is released, and modulator pressure (6) is applied to the left side of shift valve C. Shift valve C is moved to the right side. These valve movements release CPC C pressure (4C) from the back of the 1st accumulator and the 3rd clutch, and the 1st clutch is engaged securely.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
D Position: Shifting between 1st gear and 2nd gear
As the speed of the vehicle reaches the programmed value, the PCM controls A/T clutch pressure control solenoid valves A and B. LS B pressure (57) in the right side of CPC valve B is released, and LS A pressure (56) is applied to the right side of CPC valve A. Line pressure (4) becomes the CPC A pressure (4A) at CPC valve A, and the CPC A pressure passes through shift valves C, A, and B, to become the 2nd clutch pressure. The 2nd clutch is engaged with CPC pressure, and the 1st clutch is also engaged. No power is transmitted because of the one-way clutch.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
D Position: Driving in 2nd gear
PCM turns shift solenoid valve C OFF, and shift solenoid valves A and B remain ON. Shift solenoid valve C is turned OFF, and the SH C pressure (SC) is applied to the right side of shift valve C. Then shift valve C is moved to the left side to switch the port of line pressure and the CPC pressure. The 2nd clutch pressure is changed to line pressure mode, and the 2nd clutch is engaged securely. The 1st clutch is also engaged. No power is transmitted because of the one-way clutch.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
D Position: Shifting between 2nd gear and 3rd gear
As the speed of the vehicle reaches the programmed value, PCM turns shift solenoid valve A OFF. The PCM also controls A/T clutch pressure control solenoid valve B to apply the LS B pressure (57) to CPC valve B. Shift solenoid valve B remains ON, and C remains OFF. Shift solenoid valve A is turned OFF, and the SH A pressure (SA) is applied to the right side of shift valves A and E. Then shift valves A and E are moved to the left side to switch the port of line pressure and the CPC pressure. Line pressure (4) becomes the CPC A pressure (4A) at CPC valve A, and becomes the CPC B pressure (413) at CPC valve B. The CPC B pressure (413) becomes the 3rd clutch pressure (30) at shift valve A via shift valves C and B, and flows to the 3rd clutch. The 2nd clutch pressure is changed to CPC pressure mode by switching the position of shift valve A. The 1st clutch is also engaged. No power is transmitted because of the one-way clutch.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
D Position: Driving in 3rd gear
PCM turns shift solenoid valve C ON, and controls A/T clutch pressure control solenoid valve A to release the LS A pressure (56) in CPC valve A. Shift solenoid valve A remains OFF, and B remains ON. Releasing the LS A pressure (56) in CPC valve A releases the CPC A pressure in the 2nd clutch pressure circuit. Shift solenoid valve C is turned ON, and the SH C pressure (SC) in the right side of shift valve C is released. Then shift valve C is moved to the right side to switch the port of line pressure and the CPC pressure. The 3rd clutch pressure is changed to line pressure mode, and the 3rd clutch is engaged securely. The 1st clutch is also engaged. No power is transmitted because of the one-way clutch.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
D Position: Shifting between 3rd gear and 4th gear
As the speed of the vehicle reaches the programmed value, the PCM turns shift solenoid valve B OFF. The PCM also controls A/T clutch pressure control solenoid valve A to apply the LS A pressure (56) to CPC valve A. Shift solenoid valve A remains OFF, and C remains ON. Shift solenoid valve B is turned OFF, and the SH B pressure (SB) is applied to the right side of shift valve B. Then shift valve B is moved to the left side to switch the port of line pressure and the CPC pressure. Line pressure (4) becomes the CPC A pressure (4A) at CPC valve A, and becomes the CPC B pressure (413) at CPC valve B. The CPC A pressure (4A) becomes the 4th clutch pressure (40) at shift valve D via shift valves C, A, and B, and flows to the 4th clutch. The 3rd clutch pressure is changed to CPC pressure mode by switching the position of shift valve B. The 1st clutch is also engaged. No power is transmitted because of the one-way clutch.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
D Position: Driving in 4th gear
The PCM turns shift solenoid valve C OFF, and controls A/T clutch pressure control solenoid valve B to release the LS B pressure (57) in CPC valve B. Shift solenoid valves A and B remain OFF. Releasing the LS B pressure (57) in CPC valve B releases the CPC B pressure in the 3rd clutch pressure circuit. Shift solenoid valve C is turned OFF, and the SH C pressure (SC) is applied to the right side of shift valve C. Then shift valve C is moved to the left side to switch the port of line pressure and the CPC pressure. Line pressure (4) from the manual valve becomes the 4th clutch pressure (40) at shift valve D via shift valves C, A, and B, and flows to the 4th clutch. The 4th clutch pressure is changed to line pressure mode by switching the position of shift valve C, and the 4th clutch is engaged securely. The 1st clutch is also engaged. No power is transmitted because of the one-way clutch.
NOTE: When used, "left" or "right," indicates direction on the hydraulic circuit.
D Position: Shifting between 4th gear and 5th gear
As the speed of the vehicle reaches the programmed value, the PCM turns shift solenoid valve A ON. The PCM also controls A/T clutch pressure control solenoid valve B to apply the LS B pressure (57) to CPC valve B. Shift solenoid valves B and C remain OFF. Shift solenoid valve A is turned ON, and the SH A pressure (SA) in the right side of shift valves A and E is released. Then shift valves A and E are moved to the left side to switch the port of line pressure and the CPC pressure. Line pressure (4) becomes the CPC A pressure (4A) at CPC valve A, and becomes the CPC B pressure (413) at CPC valve B. The CPC B pressure (413) becomes the 5th clutch pressure (50) at shift valve C, and flows to the 5th clutch via shift valves B and A and the manual valve. The 4th clutch pressure is changed to CPC pressure mode by switching the position of shift valve A. The 1st clutch is also engaged. No power is transmitted because of the one-way clutch.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
D Position: Driving in 5th gear
The PCM turns shift solenoid valve C ON, and controls A/T clutch pressure control solenoid valve A to release the LS A pressure (56) in CPC valve A. Shift solenoid valve A remains ON, and B remains OFF. Releasing the LS A pressure (56) in CPC valve A releases the CPC A pressure in the 4th clutch pressure circuit. Shift solenoid valve C is turned ON, and the SH C pressure (SC) in the right side of shift valve C is released. Then shift valve C is moved to the right side to switch the port of line pressure and the CPC pressure. Line pressure (4) from the manual valve becomes the 5th clutch pressure (50) at the manual valve via shift valves C, B, and A, and flows to the 5th clutch. The 5th clutch pressure is changed to line pressure mode by switching the position of shift valve C. The 5th clutch is engaged securely, and the 1st clutch is also engaged. No power is transmitted because of the one-way clutch.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
2 Position
The PCM controls the shift solenoid valves and A/T clutch pressure control solenoid valves A and B. The conditions of the shift solenoid valves and the position of the shift valves are as follows:
^ Shift solenoid valve A is turned ON, and shift valve A is in the right side.
^ Shift solenoid valve B is turned ON, and shift valve B is in the right side.
^ Shift solenoid valve C is turned OFF, and shift valve C is in the left side.
The PCM also controls A/T clutch pressure control solenoid valve A to apply the LS A pressure (56) to CPC valve A. Line pressure (4) from the manual valve becomes the 2nd clutch pressure (20) at shift valve B, via shift valves C and A. The 2nd clutch pressure (20) is applied to the 2nd clutch, and the 2nd clutch is engaged. The 1st clutch is also engaged. No power is transmitted because of the one-way clutch.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
1 Position
The PCM controls the shift solenoid valves and A/T clutch pressure control solenoid valves A and B. The conditions of the shift solenoid valves and the position of the shift valves are as follows:
^ Shift solenoid valve A is turned ON, and shift valve A is in the right side.
^ Shift solenoid valve B is turned ON, and shift valve B is in the right side.
^ Shift solenoid valve C is turned ON, and shift valve C moves to the right side by the modulator pressure (6).
The PCM also controls A/T clutch pressure control solenoid valve B to apply the LS B pressure (57) to CPC valve B. Line pressure (4) from the manual valve becomes the 1st clutch pressure (10) at shift valve C. The 1st clutch pressure (10) is applied to the 1st clutch, and the 1st clutch is engaged. Line pressure (4) also flows to CPC valve B, and becomes the CPC B pressure (4B). The CPC B pressure (4B) becomes the 1st-hold clutch pressure (15) at shift valve D, via shift valves C, B, and A. The 1st-hold clutch pressure (15) is applied to the 1st-hold clutch, and the 1st-hold clutch is engaged.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
R Position: Shifting to the R position from the P or N position
Line pressure (1) becomes line pressure (3) at the manual valve, and flows to the reverse CPC valve. Line pressure (3) is regulated by the reverse CPC valve and becomes the reverse CPC pressure (3'). The reverse CPC pressure (3') pushes the servo valve to the reverse position, passes through the servo valve, and flows to the manual valve. The reverse CPC pressure (3-) becomes the 5th clutch pressure (50) at the manual valve. The 5th clutch pressure (50) is applied to the 5th clutch, and the 5th clutch is engaged with the reverse CPC pressure.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
R Position: Driving in reverse gear
The PCM turns shift solenoid valve C OFF. Shift solenoid valve A remains OFF, and B remains ON. Shift solenoid valve C is turned OFF, and the SH C pressure (SC) is applied to the right side of the reverse CPC valve. Then the reverse CPC valve moves to the left side, creating full line pressure. Line pressure to the 5th clutch is the same as when shifting to the R position, and the 5th clutch pressure increases. The 5th clutch is engaged with line pressure mode.
Reverse Inhibitor Control
When the R position is selected while the vehicle is moving forward at speed over 6 mph (10 km/h), the PCM outputs to turn shift solenoid valves A and C ON, and shift solenoid valve B remains ON. The reverse CPC valve is moved to the right side and covers the port to stop. Line pressure (3') to the servo valve. Line pressure 0) is not applied to the servo valve, and the 5th clutch pressure (50) is not applied to the 5th 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
Shift solenoid valve C is turned OFF by the PCM, and the SH C pressure (SC) is applied to the right side of the reverse CPC valve. Then the reverse CPC valve is moved to the left side to uncover the port leading line pressure (3) to the servo valve. Line pressure (3') passes through the servo valve and flows to the manual valve. Line pressure (3") is intercepted at the manual valve, and is not applied to the clutches.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
Lock-up System
The lock-up mechanism of the torque converter clutch operates in the D3 position (2nd, 3rd, 4th, and 5th), and D3 position (2nd and 3rd). The pressurized fluid is drained from the back of the torque converter through a fluid passage, causing the torque converter clutch piston to be held against the torque converter cover. As this takes place, the mainshaft rotates at the same speed as the engine crankshaft. Together with the hydraulic control, the PCM optimizes the timing and amount of the lock-up mechanism. When the torque converter clutch solenoid valve is turned on by the PCM, the torque converter clutch solenoid valve pressure switches the lock-up shift valve lock-up on and off. A/T clutch pressure control solenoid valve C, the lock-up control valve, and the lock-up timing valve control the amount of lock-up.
Torque Converter Clutch Lock-up ON (Engaging Torque Converter Clutch)
Fluid in the chamber between the torque converter cover and the torque converter clutch piston is drained off, and fluid entering from the chamber between the pump and stator exerts pressure through the torque converter clutch piston against the torque converter cover. The torque converter clutch piston engages with the torque converter cover; the torque converter clutch lock-up ON, and the mainshaft rotates at the same as the engine.
Torque Converter Clutch Lock-up OFF (Disengaging Torque Converter Clutch)
Fluid entered from the chamber between the torque converter cover and the torque converter clutch piston passes through the torque converter and goes out from the chambers between the turbine and the stator, and between the pump and the stator. As a result, the torque converter clutch piston moves away from the torque converter cover, and the torque converter clutch lock-up is released; torque converter clutch lock-up OFF.
No Lock-up
The torque converter clutch solenoid valve is turned OFF by the PCM. The lock-up shift valve receives the LC pressure (LA) on the left side, and the modulator pressure (6) on the right side. The lock-up shift valve is in the right side to uncover the port leading the torque converter pressure (92) to the left side of the torque converter. The torque converter pressure (92) becomes the torque converter pressure (94), and enters into the left side of the torque converter to disengage the torque converter clutch. The torque converter clutch is OFF.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
Partial Lock-up
As the speed of the vehicle reaches the programmed value, the torque converter clutch solenoid valve is turned ON by the PCM to release the LC pressure (LA) in the left cavity of the lock-up shift valve. The modulator pressure (6) is applied to the right side of the lock-up shift valve, then the lock-up shift valve is moved in the left side to switch the port leading the torque converter pressure to the right side of the torque converter. The torque converter pressure (91) is applied to the right side of the torque converter to engage the lock-up clutch. The PCM also controls A/T clutch pressure control solenoid valve C, and the LS C pressure (58) is applied to the lock-up control valve and the lock-up timing valve. When the LS C pressure (58) is lower, the torque converter pressure (91) from the lock-up timing valve is lower. The torque converter clutch is engaged partially. The LS C pressure (58) increases, and the lock-up timing valve is moved to the left side to uncover the port leading the torque converter pressure to high. The torque converter clutch is then engaged securely. Under this condition, the torque converter clutch is engaged by pressure from the right side of the torque converter; this condition is partial lock-up.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
Full Lock-up
When the vehicle speed increases, the PCM controls A/T clutch pressure control solenoid valve C to increase the LS C pressure (58). The LS C pressure (58) is applied to the lock-up control valve and the lock-up timing valve, and moves them to the left side. Under this condition, the torque converter back pressure is released fully, causing the torque converter clutch to be fully engaged.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
