Did you check the ring gear and pinion gear? The left side could move freely and still have a jammed up ring and pinion because of the differential gears or Spider Gears as they are called.
The axles will move independantly of each other because of the spider gears - unless they are turned upside down making it a positive traction rear end. Or welded. Which I am sure the latter is not the case.
More than likely when the right wheels hit the curb it drove the axle into the pider gears and may have locked up there, possible broken gear hub (Spider gears mount into a hub).
I doubt there is a thing wrong with the axle or the bearings. our problem lies in the center pig. Center Casing. That is Aluminum, might want to check for cracks.