Where's this noise coming from?

Check your universal joints. They can have a bit of a vibration as well as a high pitch squeal. Kinda like a high pitch chirp chirp chirp with some vibration?

Make sure there is no load on the driveshaft ( chock the wheels and then slip it out of park and then back into park, that should release enough tension so you can check them) check front and rear up and down side to side and try and rotate to see if you find some slop.