Gear Ratio question

I feel dumb asking this. Short of pulling the diff. case cover and eye-balling the gears and not having a tag on the axle, What is the prcedure for getting a rough estimate for the gear ratio of an axle? how many turns of the wheel vs. turns of the pinion?

 

first check to see if its a limited slip or an open rear. do this by jacking up the rear end, getting both wheels off the ground. spin one wheel. if the other wheel spins the same direction, its a limited slip, if the other wheel spins the opposite direction, its an open rear. do this test in 2 wheel drive.

if limited slip - keep both wheel off the ground. spin one tire 1 full roation. count how many times the driveshaft spins. that is your ratio.

if open - keep only one wheel on the ground. spin the wheel off the ground 2 full rotations. count how many times the driveshaft spins. that is your ratio.

 

I didn't know you could do that. Great info...

 

Thanks for the info.