Gear ratio?

By just turning one wheel (the other on the ground) and measureing drive shaft rotations the planetaries in the differential are spinning around. With and open diff. you have to have both tires off the ground (limited slip/sure grip also) and turn the drive shaft by hand while watching that the wheels are both rotating together. If you turn the driveshaft 3 revolutions to 1 wheel revolution then its 3 to 1.

Terry