Auxillary fan vibrations

Took a road trip to my uncle's country place about 75 miles away and back. Next day I get noticable engine (?) vibes that I suspect are related to the aux fan as they only happen when either the a/c is blowing OR without A/C and the engine is hot (triggering the aux fan). Think I am on to something? If so, how do I check/fix the issue?

Thanks!

Pete,
You didnt twist it up at Camp Jeep and pull it out of one of the mounting holes ? Can you hear any of the blades hitting anything?
Maybe it is having bearing issues like the rear end-----
Wayne

The FSM has a pretty elaborate exploded view of the fan housings
and hardware - assuming the bolts are all in the right places
(and it's not physically hitting something), it could be bearings -
or maybe worse the motor is drawing current without blowing
the fuse. Hopefully the fuse is the stock rating.