When I accelerateI hear a cluck sound have already replaced both u joints was wondering what it is hoping that it is not the pinion gear needing to be replaced from a previous owner driving to hard

Maybe the motor mounts. Do this test open hood get into vehicle put into drive hold foot on brake then tap the gas pedal with other foot if motor moves more then normal motor mount is bad do the same in reverse.

Or transmission mount, transmission itself or pilot bearing if standard. Too much gear lash in the rear end could do it also.