P8ntbala

Hey, Its been awhile since I've posted here but I was hoping I could get some advice...
I'm not sure how common this would be with older mustangs, but over the past 4 months my car has developed a loud droning noise that gets louder as the car is moving faster (not just rpm) and echos in the cabin and I believe is also quite audible from outside the car although its hard to tell. It's loud enough that having a conversation is difficult at speeds above 60ish. My GT has 101K miles.
I talked to a friend and we checked some of the bushings where the rear connects to the frame but they seemed to look fine. He also mentioned it could be bearings inside the rear axle/pumpkin that have gone bad and are causing the noise.
I have the numbers from the axle and I was planning on buying these bearings, but before I do this I was hoping maybe some of you guys would have some suggestions/advice for things to check. Hopefully its not the transmission. Thanks.

usermst9673

put the rear end up on jack stands so that the wheels are off the ground and rotate them to see if you hear any grinding or scraping noises coming from the axle tubes. If there is I can almost 100% bet its the bearing. There is 2 options with the bearings when you change them you might be able to get away with a repair bearing which relocates where the bearing rides on the axle shaft. Other option is new bearings and axles.

P8ntbala

I tried this as well when we were checking the bushings. The axle made noise when it rotated, but I wouldn't describe it as a "grinding noise". It didn't glide quietly either, although I don't really know what I am listening for.
I could probably get a friend of a friend who is basically a mechanic to listen to it... Is there another way to check for bad bearings besides opening the axle?