Well, if you don't want to work on it, go to the dealer and have them put a new nosecone on it, and in the process they have to put new oil in it.
Nosecone should be around $400, labor 1-2 hours. Have them get you an estimate.
Otherwise, here'* what it is like to take apart. You can see where the coupler is. Dealer will not install a coupler, you have to do that yourself. I think coupler is only around $50.
1) I don't know - pieces might break off and bounce all around and get ground up in the gears
2) It'* the coupler.
3) 20,000 is a lot, I wouldn't wait that long.