The primary automotive application of your lock-up basic principle was Packard's Ultramatic transmission, introduced in 1949, which locked up the converter at cruising speeds, unlocking in the event the throttle was floored for rapid acceleration or because the car or truck slowed. Visible Inspection:  Start with a simple visual inspection. https://torque-converter-clutch49360.kylieblog.com/34528643/the-fact-about-torque-converter-clutch-that-no-one-is-suggesting