well i messed around with it today, the noise is coming from my tranny... when it starts i put my ear down towards the shifter and i hear it well. if i just coast in whatever gear it stops, but if im going at a steady speed at lets say 55 mph down on fifth gear, it howls. btw i have 3.73's with no speedo gear change, so i really dont know what im going..... i dont think its the gears if they stop when i accelerate and when its coasting... they spin as long as the cars moving i think?