While I've never truly worked on aircraft, it really does bother me when things start making new noises! I too have an ME background & more than a few concentrations/CECs in FEM/FEA and vibration analysis; not that I really use any of that stuff much any longer in what I do... I actually did my master's thesis work for the ONR in an effort to extend the service life of the flaperon actuator on the EA-6B Prowler; lots of FEA & fatigue testing of scaled down models.

Anyway, I just finished up the rear wheel bearing replacement on my wife's '14 Impala. I waited almost a month for the noise to get worse in hopes of really being able to tell the true culprit as both rear bearings felt the same with the brakes removed (just the hubs themselves being spun)... Just for good measure to make sure that it wasn't road noise from the aggressive snow tires, I threw on her old all-season tires; noise still there which I was fairly confident that it would be given the frequency of the noise as it sounded like a ball-to-race defect-esque frequency. I had to ride around in the trunk for half a country block to get a better feel for which rear wheel bearing it was... And then I fought for a few hours getting the steel bearing out of the aluminum knuckle. Good ol' NY likes to forge those two materials together with all of the lovely de-icing chemicals they use... But it's done and the car is quiet as a church again!!