http://www.tccoa.com/articles/tranny/transmission/page5.shtml the "I hear a buzz from my tranny" paragraph. It can be very annoying, and the article says it can cause parts to wear (I always thought it was just a live with it thing). I thought that you couldn't just swap in a newer main control because the locator pin size changed, but I have never tried. I had a friend with the buzz in the tranny and it was annoying, like a fuel pump going out x20.