I always recommend that you eliminate the torque converter from your transmission to diagnose it appropriately. Present day torque converters have Digital control of the clutch operation. The tension within the torque converter clutch is controlled via a key regulator valve that is piloted by a solenoid (see pics over). https://torque-converter-clutch08517.worldblogged.com/40308174/what-does-torque-converter-clutch-mean