1990 MJ, 4.0, aw4, np231
truck recently started knocking, very loud and from underneath. Flushed the oil with fresh oil Incase it was an oil issue, no change. Engine running absolutely perfectly I should add. Checked flex plate bolts and one was loose, tightened up and still knocking but not as bad, still bad though. While underneath tightening the flexplate bolts and revolving flex plate, it sounds as if something is interacting with the thin aluminum spacer that is inbetween the trans and engine, sounds like a small pop at about 12-1oclock when rotated by hand. Any chance the flexplate would not be square, for lack of better term, or wobbled itself out of square with the loose bolt? Any benefit to loosening all flexplate bolts and retightening in a cross cross pattern?