You can make a mark on the flywheel and the driveshaft and turn either one a single revolution and see what your ratio is. It is probable that it you can either hand turn the prop shaft by hand with the coupler or a pipe wrench. Since it is a step down transmission, that would be easier than turning the engine over manually. If you want to turn the engine over carefully, (key off, power off, etc.), put a socket and pull handle on the front of the engine crank shaft. Usually there is a nut on the front crank holding the timing wheel / balancer / front pulley on.
Don't make the mistake my Dad made and leave the pull handle on the driveshaft when cranking the engine
Big mistake and glad no one got hurt, except the Craftsman pull handle (twisted in a big U shape). No, he wouldn't use their warranty, assuming someone would ask how he screwed it up...
Stu
