1. Index the input (the part that goes in the engine) and the output (the part that goes to the drive shaft) shafts with a thin line. Make corresponding lines on both ends of the transmission case to use as your pointers.

2. Put the transmission in the gear you want to check.

3. Turn the input shaft until the tail shaft makes one full revolution. The number of turns made by the input shaft, including fractions, is the ratio for that gear. High gear is almost always 1:1, over drive will be more than that but the lower gears will normally produce less than one full revolution of the tail shaft. To make this process even more accurate turn the input shaft until the output shaft makes ten revolutions, then divide the number of revolutions made by the input shaft by ten (duh!).

4. To determine the final ratio for running in that gear multiply the transmission ratio by the rear end ratio. Do you know the rear end ratio?
To find out, index the input shaft (yoke) and the rear axel. Turn the yoke until the axel makes one full turn. The number of turns made by the yoke including fractions is your ratio.