BAN WS6

I bought my WS6 with an aftermarket Hurst short throw. I love the tight pattern but the damn thing rattles like hell. In town it's not really noticeable, it's when I'm on the interstate or highway. I'll drop it in 6th, running 85 or 90 and it just rattles and vibrates, sounds like metal on metal. All I have to do is keep my hand on the ball and it eliminates the problem but occasionally having to do this gets annoying, any advice?