Spun Main Bearing?
So I have a 96 4.0L Ranger. I let my father use it for about a month while I was at school and now there is a loud knocking sound under the hood and I don't think it's even driveable. I haven't tried nor have I put a stethoscope up to it, which from reading other forums, is what I should do? However, what I'm trying to determine is whether or not my dad's prognosis could be viable. He believes that it is a spun main bearing. SO my question is, what does a spun main bearing sound like? And what does a busted rod sound like? This sound is pretty freaking loud, and there's chemical/burning smell upon disengage.