to find the gear ratio of the vehicle. Put the back up on jack stands. Put the car in nuetral. make a mark on the driveline or pinion yolk and on the inside of the tire where you will be able to keep track of revolutions. turn the drivline. keep track of how many time the driveline must turn to make one full revolution of the wheel. Done! 3.23 to 1. 3.91 to 1. etc. etc. etc.
