I believe your truck has to actually move forward a few feet to engage your auto hubs. So you driveway diagnostic (spinning rear wheel/front driveshaft) might not have been adequate to target your hubs. If everything dissassebmled/reassembled ok with no indications
of wear/breakage, I would claim no harm no foul. As for the noise. I have noticed that a nice chunk of ice or mud falling from the inside of the wheel well onto the the tire can sound pretty bad. In your case: 1st bump loosened chunk for rubbing/grinding, 2nd bump broke it off/away so no more noise. I would still go to manual hubs though!! Good luck

JD