My Buddy has a 1979 F250 with a Dana 60 in the rear and it puzzles us. When the truck is in nuetral and you spin the rear wheels they spin together in the same direction as if it has a posi. But we know for a fact that it is a open rear diff. We have had the cover off and it is an open carrier. We cant check the door tag because they are not original. If you have any idea why it acts like this please respond.

Thanks  

When u say u spin the tires in neutral you mean u have the rear wheels off the gound rigth?  Normally when they are off the ground one tire goes in the direction u push it in and the other goes in the oppisite direction.  

Yeah the tires are off the ground. And that's why its so confussing because the tires spin the same direction  

It simples means that your spider gears are tight and dragging. It could be that the shaft they are on or the thrust washers the ride on are scarred or damaged preventing them for turning freely.