I've been trying to pinpoint where a whining noise has been coming from for about a year now. Its been progressively getting worse and I can't stand the noise anymore.
When backing up, I hear a squeak, squeak, squeak but I don't hear it in drive. But when I'm getting up to highway speeds, the whining gets louder and louder and when I decelerate, the whining goes back down. I recently had the transmission rebuilt which I thought was the problem but the noise is still there. While doing 60mph, I shift to neutral and the whining is still there. When I downshift going up a hill, the noise gets worse.
I've read some other threads on here on U joints and some are having similar problems. I got under my truck and tried to move the driveshaft but it wouldn't budge.
Any help or advice would be greatly appreciated.

 

Pinion bearings in the diff most likely, otherwise it is the physical gears themselves (ring and pinion gear/spiders).