I am sitting here at work pondering about my 7 1/4 rearend in my 71 Duster, and realized that it may be no good. I had the rearend jacked up yesterday and was able to spin the rear wheels, while the car was in park. The rearend is an open rearend. Is that wrong or am I missing something? I didn't think that I should be able to spin the rear wheels when it is in park. I tried to spin the driveshaft by hand and it would not spin. Am I losing my mind or do i need a new rearend?