4WD Problem

[CO71Blazer]

I have a problem with the 4WD in my 71 Blazer. When I lock both hubs and put her in 4Hi my right front tire locks. It just drags and does not roll. I've pulled the hub apart and can't see anything obvious. The Warn Premium hubs look to be in working order. Wheel nuts are torqued to spec, and on jack stands everything appear to turn correctly. My brother thinks I have a diff issue in my D44. I know the front drive shaft needs to be rebuilt but I'm at wits end, and three wheel drive is not going to cut it. I need to pull the cover off the front differential and take a look, but I wanted to see if anyone had any ideas before I just tearing things apart.