I recently did this for my granddaughter's first vehicle--a 20 year old pickup with a manual tranny. Surprisingly, there is not a standard threading for them, so you'll have to see what's on the vehicle. A bottle stopper mandrel, if you have one, would be one easy way to hold the wood while turning. Since the threading in the vehicle is almost certainly not the same as the mandrel, you'd have to redrill and thread or put in an insert. All in all, a fun little project. (Since my granddaughter is a rocker and an artist (and a terrific kid), I made a plain vanilla knob that she can decorate as she likes, then we'll apply some acrylic or poly.)