Since I had my OEM short shifter installed I've been hearing a rattle from my shifter under harder acceleration. It's a very annoying buzzing sound that goes away when you grab the shift knob. I though it was the shift knob itself because it has that gray washer type thing thats on the bottom of the knob itself. I bought a Prodrive shift knob and the noise got better but it's still there. Anyone else have this problem or have any suggestions?