I've read in some reviews that they need to be sanded to fit. I figured I'd have to do the same because it's slightly larger than the driver's side hole on the Dana 30. So I used steel wool to clean the inside of the mounting hole and smooth the outside. Sleeve. I then oiled both surfaces and then went to town with a jack press. It needs to be aligned properly and then with some force cut that little excess off the socket and from there it just needs a lube on the elbow to get the socket all the way in. With the necessary power. Putting that jack in, I know it's going nowhere. Can't say anything about durability yet as I installed it yesterday, we'll see.