Grinding sound from X/Y motion

All of a sudden I am getting an low-frequency grinding sound during X/Y travel. Sounds something like belt teeth grinding, or tires over bad pavement. But it seems unaffected by me manipulating the belts during travel, so pretty sure its coming from the motors. Tried to record but all you can hear is the normal motor whine. Z sounds fine.

What could cause this to happen to both X/Y simultaneously? Other than just bad luck.

I’m having some grinding on my y axis- ever figure yours out?