Rear diff. questions 1950 Flathead V8 F1

[Cap'n Dick]

I recently completed several upgrades on my F1. That included a 12V conversion, electric fan with shroud, new DC Holley 94, et. The motor started quickly and runs great. I started to back out of the garage and heard a loud metallic bang, which I can't identify. I quickly discovered a major leak from the right rear brake drum area. Everything was a mess. Covered in brake fluid. The wheel cylinder had failed. The truck is on jack stands. I rotated the passenger side wheel, which turned fairly easily. The drive shaft was rotating. Trans. is in neutral. Did the same on the driver's side. The wheel spins freely. No noise or resistance. The driveshaft doesn't move. This is where my knowledge is weak on this truck. I don't know what is supposed to happen on the driver's side. Should it also move the driveshaft. Acts like it isn't connected to anything. Any comments are welcome. I'm rebuilding the failed brake and would like to drive it for the first time in two years. Thanks, Cap'n Dick