Broken Axle or Shelled Rear

I bought an 84 Pete 359 EXHD from a guy here in town and he kind of abused the poor truck. When I bought it I knew the main drive was bad but bought it anyways as it was cheap and I was looking for a project truck (and I'm a sucker for 359's). It'll drive with the power divider kicked in but I haven't driven it more than a few miles to the lot it's at now because the good drive cracks and pops which I believe is the power divider jumping gears.

The man I bought it from pulled an end dump. He said his driver got off in some mud one day and got stuck and dumped the clutch a few times trying to get free...

Anyways, I haven't had a lot of time to work on it but once every now and then. I've been thinking I needed a new set of rear ends and it probably shelled some spiders but when you jack the main drive (the bad one) up in the air, you can spin the wheels freely and it's dead silent. I've had a few guys tell me if it was the rear end then you'd hear and feel it cracking and popping and that it was more than likely an axle. When I disengage the power divider and let the clutch out where I should be moving, it does nothing but spin the drive shaft. No popping or cracking can be felt or heard. When you jack them up in the air and spin them by hand, the other side starts to spin opposite for a few seconds, then it slows down and stops, either way you turn them. I want to say if you spin the right side the left side doesn't move at all but I don't remember for sure. I've been meaning to work on it more, but it's been too cold and crappy outside or I've had other more important things besides my huge hot rod. I've had the passenger side axle out to change a gasket but that's it. It was fine.

I guess my main question here is, what are y'alls opinions on it? I know I won't know for sure until I get that axle out which will be this weekend. I've had multiple shops tell me it's more than likely an axle including Inland Truck Parts. That would absolutely make my year. If it matters, the truck has a 3406A, 12513 with Rockwell SQ100's-unknown ratio, truck has a cutoff.