So I had the rear end jacked up, both tires off the ground, no drive shaft in the car, no engine or tranny in the vehicle yet either. wanted to see if the 489 was a sure grip. I rotated one rear tire forward, expecting and hoping to see the other rear tire turn in the same direction. The other tire didnt move. I tried reversing the direction, same thing, the other tire didnt move. I had read that if it wasnt a Limited slip diff, the opposite tire would spin opposite way. So I was expecting the other tire to at least move. Whats the deal. What am i missing here? thanks