Bad differential ??

Sorry for the delay, (long story) and thanks for replying!!

Yes, the noise went away when I put the open back in. Hard to say if the noise changes with vehicle speed, what with the TTI exhaust so loud.

I am planning to just assume that I will replace both of the pinion bearings, the oil seal, and the crush sleeve.

This is the 8 3/4 rear axle, and it is the "best' one known as 489 if memory serves me.
Can anyone tell me what are the part numbers I need, or what are the "bearing" numbers I need so I can just go to a "bearing" store to buy most of these parts? Or can you recommend a good place to buy all 4 items at one place?

Thanks, Tim