read through these threads it will give you all the information you need to know about "gear whine" in the differential. Early 04 models had a faulty differential that eventually whines due to misalignment when driving at higher speeds. Its covered by the powertrain warranty if that car has it. Its a one day fix. However if its not under warranty forget it, the part costs about $3000. Make sure to read these threads...

https://www.crossfireforum.org/forum/...t=differential

https://www.crossfireforum.org/forum/...t=differential