Modern day torque converters use electro hydraulic control for that lock-up clutch. The hydraulic circuit which locks/unlocks the torque converter clutch is managed using hydraulic valves. The valves are actuated specifically or indirectly by solenoids. However, Like all mechanical element, torque converters can don out or malfunction with time. Comprehending https://damienmgtgr.blogocial.com/torque-converter-clutch-an-overview-69745674