shifter bushings. Loctite would work also, but I dreaded having to forcefully remove the shift knob again in the future. I'll still swear the virgin removal was the toughest piece on the car I've removed. Like Peter said, a tiny folded piece of paper jammed up into the threaded cavity works great - it'll make the lever bottom-out before reaching the end of the threads. Just add or remove paper to get it clocked to your preference.
