Renewing and getting the right preload on the lock-up clutch on the 5HP24 torque converter is a specialist job because it’s a friction welded assembly.

http://www.xoutpost.com/863854-post40.html

Even if the TC was replaced with the transmission it’s possible that the LUC in it hadn’t been touched.

If you cruise along at 60-70mph and quickly remove your foot from the accelerator do the engine revs stay the same or does the engine speed suddenly drop?

Phil