Whining
 

New to the group sorry, if i missed this discussion.
2005 F150 four door 9.75 rear end made a whining noise from 40 mph on up. Replace it with a remand from O`Reilly`s and it was worse than the first. After a month of arguing I finally got another rear end and it whines as well.

What are the odds of three rear ends making close to the same noise or am i chasing a transmission noise through the rear axle. (Side not when you let off of the fuel pedal it goes away. Thank For Any Help