2001 FORD E150 whinnig rear end
It sounds like your bearings, and/or ball joints, maybe damaged, and in need of repair. Is it more like a squealing sound, or a whining sound?
new bearings was put on axles but did not help it's whining sould and gets louder the faster u go
Most likely the ring and pinion bearings are shot, if you wait too long you will be replacing the whole unit.
See @TennisShoes answer above, I think they're correct here.
Looking for a Used E-150 in your area?
CarGurus has 2 nationwide E-150 listings and the tools to find you a great deal.
Search Ford E-150 Questions
Ford E-150 Experts