Circlip time! Ok, so I decided to bust out my macro lens and take a nice macro closeup of both sides of the circlip so that everybody will understand exactly what we are talking about when we say the "flat" or "sharp" side, and the "round" or "beveled" side. Side by side, it should be a bit more obvious here. Take note of the arrows, and you can see where/how it is particularly easy to spot the difference. The flat side is literally flat, like it was sanded down, and the round side looks beveled. The flat side should be facing the inside of the diff, and the beveled side should be facing the thrust assembly.