It's not that the car rolls forward, it's lunges slightly like someone is jumping on the rear bumper while it's in park. It happens when while it's running, and also happens to me after I shut the engine off (up to 2 minutes after)! I literally just had the transmission rebuilt after 140K (pump went bad), but that didn't fix it.
It's almost like energy is being built up somewhere in the drive line, like a rubber band being twisted, and then suddenly released. Is there a center bearing in the drive shaft on these? Someone mentioned the possibility of brake calipers getting stuck, but I don't think that would be it. Ideas?