1956 F100. Truck had sat for awhile. Started up and dorve a short bit. After that it wouldn't move. DRY! Left wheel and drive shaft move. Right is stuck. It will move a half inch or so each way, then stops. What do I have to do to git it to move?

 

Welcome! Are you sure the problem is in the differential? Did it make any loud noises, smell bad, or get hot before it locked up? And just how abrupt was the sudden stop? Could it be that a bad wheel cylinder on the right rear has locked up that side? Jack up the right rear and see how easily the hub comes off. Also see if you can turn the axle.

 

Thanks, I'll check it out some more.