Originally Posted by Modshack

I went through this on my Vette with an aftermarket shifter...It's not the knob. The problem is that the driveline vibrates. A stock shifter has enough slop and damping rubber built into it to mask the transmitted vibration and noise, making it generally acceptable. When you tighten the tolerances in the shifter and remove the OEM damping built into the shaft, you get vibration in the shifter and mechanism. This translates into a rattle in the shifter assembly. Not much you can do....