snap ring, plus I have 3-4 other diffs laying around and parts are a pita to get and $$$. Plus its a PITA to get it out.I run carpet so its hard on the diff and they don't seem to last long. I think the 210 mid motor 4 is the best carpet car I have ever driven. And I have them all losi RB6,B5m,ect. I would spend the$$ if I was inclined to believe Durango won't go bye bye--I hope they don't.