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| Illustration 1 | g00277579 |
(1) Upshift solenoid. (2) Downshift solenoid. (3) Lockup solenoid. | |
For the speed positions that require the option for direct drive, the lockup solenoid must be activated after the upshift solenoid or the downshift solenoid is deactivated. The position of the transmission gear switch and the ground speed signal from the transmission speed sensor command the EPTC II to activate the lockup solenoid at the correct time.
The lockup solenoid sends signal pressure to the relay valve in the lockup clutch and synchronizing valve. This allows oil in the transmission charging section of the transmission and oil torque converter oil pump to flow through the pressure reduction valve in the lockup clutch and synchronizing valve. This oil flows to the modulation reduction valve in the lockup clutch and synchronizing valve. The oil from the relay valve also acts on the selector piston. This allows the oil from the modulation reduction valve to flow to the lockup clutch. The lockup clutch will stay in direct drive until the oil pressure is removed by the lockup solenoid.