From what I understand it is here:
Well I didn't blow up the Bronco's rear end.
The one spot that I didn't check the screws after last weekend was the rear diff...... turns out the 3 screws that hold the 2 diff halves together had backed out.
I tore the whole truck apart, cleaned the Tamiya grease out from the PO and filled her up with my favorite grease (Superlube). Ready to go next weekend.