You know, that is a possibility... my 04 is supercharged, but now that I think about it, my 01 GTP had sort of the same problem, too...

I do remember hearing a little transmission grind (in both cars) when I back out of my garage... I think it's associated with that. I took it to the dealership and they said it was common and there was nothing to worry about. Let me know what you think or find out.