After a hard hit in the desert, I experienced a ticking/grinding noise when putting the truck in reverse. I was perplexed how the hit could've caused it, as it was only in reverse. It was not until I had another person put the truck in reverse while I looked under the hood did it become clear - the engine was rocking over to the driver's side while in reverse and the fan was contacting the fan shroud.
I figured I broke an engine mount so I took the truck down to the shop to have it replaced. We threw it up on the lift and to my surprise the mount was fine. It wasn't until closer inspection that we noticed it had pushed through the frame on three sides. The motor mount had pushed through the frame on three of its sides, leaving the top side attached.
The shop bent it back out, welded it in place, boxed it up, and gusseted the mount. Good as new, $200 in fabrication and $69 for the front diff. service (front driver's side axle had to be pulled to get at the mount).
Lesson learned - gusset your stuff. I knew I needed it, but kept putting it off.