Your situation sounds exactly like mine. I had a leak at the ball, but more of a leak at the rear of the "tube" where the collar threads on. I had a gasket set and thought I would just slide the collar back, remove the old seal, slice the new seal, put it around the shaft, apply a drop of super-glue and tighten everything back up. I spent several hours trying to do that and gave up. When I unscrewed the collar and slid it back, I never could get the two washers and old seal to come out of it. I tried pushing all sorts of thing screwdrivers up into it with no luck. I even cut some sheet metal and made sort of a pusher to slide up into that groove and push those washers and seal out. No luck. So, I ended up having to remove the entire u-joint (trunnion) to be able to slide that collar off. I'm glad I did because I discovered that my u-joint is scarred up pretty good, so I'll be replacing that. I did all this today, and this is a first for me on this type of truck. I'm learning as I go.