well today i was driving my truck cause the top seam on my rad is leaking and the rad shop is closed so i am coming home and i make a left hand turn and then happens to my 77 f-250SC but i am boggled cause i didn;t hear anything break like when i was with my friens i heard a loud pop then his axle was out like that mine just came out its a Dana 60 BTW and all i want to know is what would cause this

 

does it have clip style axel retainers?

 

i don't remember i don't mess with it until maintance time and that was like 7 months ago
here is the pic

 

the picture doesnt work

 

thats less than a min after it had happened in the middle of the road