open diff gearing question.

So last nite I was trying to verify that I have 4.56 gears in my open diff, even though I already checked the door code, I was curious anyway.
I wasn't quite sure how to do it and eventually figured it out. (was only turning the wheel 1 full revolution and initially had both wheels in the air).
Initially I jacked up at the rear diff and raised both rear wheels off of the ground and proceeded to turn the wheel 1 revolution. Naturally the other wheel turned in the opposite direction.
What i then realized was that I had never taken the transmission out of park.
Is this normal for open diff carriers?
Is it because there is no resistance on the wheels?

I would think that if the vehicle was in park that the transmission would be locked preventing the rear wheels from turning at all.

Thanks in advance.

 

eh...I cant remember. I was to concerned with why the tires were spinning at all.

Come to think of it, I dont think it was. That was what made me think about what gear selection I was in. Then when my buddy looked to see he was like "wth", it's in park.

 

Thats what I figured. Thx