Rear end noise

Hello again everyone,
69 dart gts, 8.75 rear end. I’m not sure how to explain but I have a like grinding noise coming from the rear. You don’t hear it until you get up to 10+mph. I have zero idea where to begin and dont want to start taking things apart blindly. To me, the noise is coming from the area at the end of the drive shaft. I have video running it on jack stands and you can hear the noise after I shut the car off, I’ll try to link those videos. Any direction would be appreciated thanks guys.