In short, I've blown out the plastic diff gear twice and decided to get a Robinson Racing hardened aluminum diff gear. I accidentally purchased a ball-diff gear (which I don't know as much about, and don't have all the additional parts for), so I am going to get this:


My question is, how do I install it? Do I just put it in like normal and squeeze it between the outdrive shafts?

Currently, the plastic diff gear uses black plastic rings to help squeeze it together like this:

Are there additional rings I need to get before installing the metal gear? I just don't know if it's going to grip very well.
Any help would be greatly appreciated!!!