If that's it with the surface rust in the last pic then it's a gov-lock. These are notorious for grenading with any sort of traction or in off-road situations where the tire comes off the ground then comes back down on solid rock. It's a ratchet style unit that works well in slippery stuff(ice, snow,mud,boat ramps,etc.) but on solid dry surfaces eventually it'll get caught in between the free-wheel/lock-up mode and all heck breaks loose(along with everything else). Someone more knowledgable than I can chime in about whether the rust on the press-on carrier bearing surface is terminal or can be serviceable.
