I'm working on getting a '51 3100 back on the road and currently going through a 216/235 swap. I'm an amateur at auto mechanics so I'm relying on the excellent advice I find on this forum. I just removed the transmission and have a question. I pretty certain the transmission had a rebuild prior to my purchase of the truck and I'm not sure whether any other work was done on the driveline. I don't know if anything has been done with the differential. May be a dumb question, but is there any way to determine the gear ratio by rotating the driveshaft X number of turns, then measuring the rotation degrees of a rear wheel?