Anyone ever rebiuld a Diff assembly? mine is noisy

 

Yes. When is it the most noisy? Going down the highway at speed? Does it change when accelerating or backing off the throttle?
How about when turning, is it louder going left or right? Try this, straight line driving until you can hear the noise when lightly apply
the brakes (drag), can use the hand brake. Listen for any noise change. This test is to check for possible wheel bearings.
Want to be sure it's the diff.