I'm noticing when I decellerate while in gear (any gear) a supercharger whine is made, I know there a slight whine before but it has seem to get much louder over the course of a day. Just wondering if this might be a prelude to a worn belt.

This only happens when in gear (not the diff) and i'm thinking is a belt maybe a small exhaust leak maybe tranny.

I'm was hoping my car was pimped with a supercharger while I was sleeping the night before, but when I looked it wasn't.

Thanks

 

wouldn't that rock though?

 

I get a similar whine from my diff (only when in gear) when its hot from being worked out and I use Mobil1. I know you said it wasn't your diff, but if you have an 03, when is the last time you changed your diff fluid and what did you replace it with?

 

Changed out about 10,000 miles ago with Amsoil Synthetic Gear Lube 80w90 GL-5

I picked up a couple weeks ago Motul 75w90 100% Synthetic but haven't had a chance to put it in