Hi Scotty just want to say your videos have helped me multiple times and I like how you make them very quick and to the point. I have a 2009 mustang and I hear a rumbling sound when I’m driving 45 or more. The only way I can describe the sound is it sounds like normal tires rolling but louder. The tires are only a few months old and I got them balanced not even a week ago because I thought that was the problem. I replaced both front wheel bearings when I first heard the sound and it went away. Then about a month later it came back again so I assumed it was the rear axle bearings so I replaced both of them and their seals and put new differential oil fluid in. The noise is still there so I’m thinking it’s now a bad U joint or what could be another possibility just so I can diagnose the problem and fix it. Thanks a bunch keep it up!

here's how to find the noise for sure, it always works (put the device on the rear end first cause it could be just worn out differential gears) https://www.youtube.com/watch?v=pqh1oH8mEqY

Thanks for the quick reply will try it when I’m off work