1999 Trans Am LS1 rear-end whine at 60-80 acceleration, any suggestions?

[VIK8423]

I bought a 99 trans am that it's modified. I just noticed an annoying whine coming from the rear end at around 60-80mph. It's only when you accelerate at those speeds. If you let go of the accelerator you won't hear anything and once you get back on the gas you'll hear it again. What could it be? Will replacing the fluid help?

 

[[email protected]]

sounds like you have bearing noise in differential maybe the pinon & ring gear. needs to be rebuilt, fluid change won't help