A solenoid is really a linear electrical actuator. When is being energised (provided with electric Electricity) it pushes or pulls a rod which is linked to the hydraulic valve. You'll find different types of solenoid employed for torque converter clutch Handle, although the theory of working is essentially the same. https://torque-converter-clutch31963.thezenweb.com/5-tips-about-torque-converter-clutch-you-can-use-today-72020057