The initial automotive software of your lock-up basic principle was Packard's Ultramatic transmission, introduced in 1949, which locked up the converter at cruising speeds, unlocking if the throttle was floored for rapid acceleration or since the auto slowed. At some point, galling with the mating elements happens, which triggers seizure. https://knoxopnki.laowaiblog.com/32979912/not-known-facts-about-torque-converter-clutch