Hello, 2001 mustang Gt with 200,000 miles. Recently replaced entire rear suspension, upper and lower control arms, shocks, all bushings and noticed a slight leak at pinion seal. Ordered new seal and wheel bearings along with 75w140 gear oil and some friction modifier. Here's my problem, I had a stuck rear driver side caliper that was hanging due to a faulty piston and the car developed a humming so I assumed wheel bearing over heated. While waiting for that to come in I went ahead and replaced the suspension parts I already had on hand. I took it for a test drive and now the sound is much more pronounced. I've never had a bad u joint but after looking through several videos on YouTube I found one that sounds very much like what my vehicle is doing and it was a u joint. However, also videos with wheel bearings sound similar and pinion gear bearings being smoked. I will say the noise does seem to reduce some when I let up off throttle. This leads me to believe it's not the pinion bearing (I hope!) because typically I've found the noise gets worse on decel due to bearing loading of it is the pinion bearing. I'm going to go ahead and replace the wheel bearings since I'm going to have the cover off anyway to do the pinion seal since I know that's bad and resealing the cover plate. Just looking for some advice on if I should also start planning to have to rebuild the entire rear end due to the possibility of it actually being the pinion bearing. I can do most work and have on this car but the rear end tear down is admittedly beyond my scope of abilities so I'd be looking at probably 1000 dollar bill all said and done. Thanks for any insight!