Differential Whine (Revised Factory Diff with Cooling Fins?)

lewie145

I just purchased a 2011 370z 6MT with Sports and Touring packages, the car has 14k miles on it. I have been experiencing a whine at 50mph+ and am fairly confident it is the rear differential. The whine only occurs at higher speeds in all gears 4,5,6 and still occurs even when car is in neutral. I have searched this extensively and found there is potentially a revised factory differential with fins according to the post below, but cannot find out any other information besides what is below on page 7.....

DIY: Rear Differential Oil Change

Has anyone else had their differential replaced by the dealer with this "revised" version that has cooling fins?

I am under factory warranty til Sep 2015 and have made an appt at a dealer this week, but would like to come as prepared as possible because i am sure they will try to say this is normal or they don't hear it etc...

Thanks for any other information you guys can provide.