There is a part that slides in to the back of the box, if that's what you mean. There is a doughnut that attaches to it, the prop then attaches to that. It's messy if it comes out as all the gear oil comes out with it
As I needed the prop off anyway I took the 3 bolts out that connect the prop to the doughnut and did it that way. It's only the second engine I have ever removed, the first one I have done without help so I am sure I did most of it the hard way
Well chuffed to have done it though and without injury too.