I just picked up a cheap dana 70 for my truck and was wondering just how strong those weird tractor type joints in the closed knuckles really are. It came out of a 70s dodge w300. I have never seen anything like them before. They look stronger than a u joint but i have a feeling they would be hard to find to replace. And any tips for improvement or the best way to keep those things lubed in that closed knuckle would be appreciated.