+1. Open differentials can easily spin both. Its only when one wheel has significantly less traction than the other wheel that you get one wheel spin. Either the way I mentioned before or lxman1's way will tell you for sure.

 

I stand corrected and educated......thx for the clarification.

 

I jacked one wheel of the ground. Tried to spin the other. It was locked. I also went to the dealership where I purchased the vehicle and the had records of servicing both the front and rear axel housing. Look like I am good for another 15,000 miles. Next time I go to service it I will just have to buy the additive for a limited slip diff.
Thanks,
everyone