Bolts for the starter working loose? I had to put a longer bolt in mine and put a nut on the other end of it to keep it tight. The threads seemed tight, but they were stripped in the aluminum bell housing, just enough to allow the starter to grind.
'87 YJ, 4.2L built and bored, 8.5" of lift, 8.8 rear, AX15/NP 231, Tom Woods drive shafts, Flat fenders, 12,000LB winch, Custom bumpers, Rattle can paint job. Never completed...