lockup problem
The overrun clutches are never applied in OD/4th gear, meaning there is no engine braking and it would be hard to feel the difference.
However to answer your question...
You need a scanner that shows/logs the TCC lockup signal to compare what your PCM is command versus what you feel is happening. If the trans/converter is following the PCM commands you know nothing is wrong with the hardware.
If the PCM is commanding unwanted shifts/lockup, you then check sensors and even the tune to determine why it is doing so. In rare cases, the PCM is defective.





