Lock-Up Control

Lock Control:

2nd, 3rd, AND 4th GEAR
The operating pressure generated by the shift valve A is applied to the shuttle duty shift valve, which pushes the lock-up control valve to the "engaging" position. Since the lock-up operating pressure is applied to the engaging side circuit while the disengaging circuit is drained, the lock-up clutch is engaged by the pressure difference.

The duty solenoid B is controlled by the TCM and controls the operation of the lock-up control valve. Because the lock-up operating pressure is controlled by the lock-up control valve, the force applied to the lock-up clutch is controlled for smooth clutch operation. When locking up, the clutch is set in the half-engaged state beforehand. After this, the lock-up operating pressure is gradually increased to achieve smooth locking up.

1st GEAR, N. R. AND P RANGES
Since no operating pressure is generated from the shift valve A, the shuttle duty shift valve sets the lock-up control valve in the "disengaging" position.
The lock-up operating pressure (torque converter regulator pressure) acts on the lock-up clutch disengaging circuit, while the engaging circuit communicates with the oil cooler circuit. Accordingly, the lock-up clutch is disengaged by the pressure difference.