this is a really stupid question, so please, just consider it from my "old timers" diseased mind ! what is the spline diameter of the 18 spline shaft ? here is the reason for asking. sunday, a buddy showed up with a plastic pilot tool that had 18 splines. however, it was just a tick over 5/8" in diameter, and the pilot was only about 7/16". neither one of us has a transmission, but i said it looked way small, i "thought" it [the spline] should be closer to 1" or so ? i tried the google, but didn't have any luck. so, help this dum old guy out, please ? TIA as always !