Getting the noted sound when lifting off of the throttle at speed. Frequency of the noise changes with vehicle speed. I've changed the rear u-joint but still getting the noise. Anyone else have this and know what it is?

 

Could be a pinion bearing or the front u joint. even if its tight it could be dry. if its four wheel drive check your t case fluid. could be an output bearing from it or the tranny. Does the sound change when applying power or letting off the gas?

 

Edit sorry i missed that first sentence my bad. anyway i would lean toward the pinion bearing or one or both of the side bearings in your axle.

 

I had a similiar sound when my carrier bearings started going in the rear. And it wasn't so much the carrier bearing as much as the racers for the bearing. I've heard of this problem with GM rears from time to time but without hearing it personally it could be anything... Maybe even a " muffler bearing" . Just kidding. All u have to lose is some rear diff fluid and gasket to just pull and check. I wish u luck because chasing a bearing issue is never fun