Does anyone have any idea why i would hear a whirling noise coming from the rear of my truck at around 35-45 mph? It sounds almost like an empty grocery or plastic bag whipping in the wind!

 

I'm having the same noise. Changed U-Joints and axle bearings but it's still there. Anyone ever figure this out?

 

Gears? Have you checked the oil or changed it and checked the ring and pinion?

 

There is a TSB out on this rear end whine. It states that bearing clearances and/or preload is too tight. Kit has bearings to replace carrier bearings and check the ring and pinion set while they are there. Just got back from my ford dealership about it. @ $1400 to repair. $481 for the kit and 6 hours labor later it might be fixed.