IIRC it was theorised that this is actually from the gears in the Tranny. Not %100 certian but I'm pretty sure that was it. By that logic it is a problem for MTX's only. I have it too. Granted it is not as bad as it used to be and now that I have a ribbed aftermarket flex pipe I have a new more pronounced whistle to contend with. It is much more audible then the other one.
