If you read the post you would have read that it has had new carrier bearings installed and obviously at that time would have been checked to see if it was "broken" !!
I had a clutch type once that had been rebuilt before I bought the car, and it acted like a spool. The last straw was backing it into a parking spot and it left a black mark from dragging one wheel.
Then I hired another guy to change the clutches, and it did the same thing. I quit throwing money at the problem and researched it myself. It turns out there are different clutches IIRC for Dana and 8-3/4. Same size, different thickness. The next time it was rebuilt, I made sure to get the right parts and did the work myself after some study. Problem solved.
I don't remember trying to turn mine manually because the problem was obvious.
