13 spd problems

Well, since reading all your responses, and having my worst fears confirmed, I have dropped some not so subtle hints to the guys I work with that I'm going to need to do this soon before it leaves me stranded on the side of the road somewhere. I could wait for the shop to do it but I would like it done before I collect social security.
So, some of the guys I work with have said (imagine a bunch of truckers now) "Hell yeah! Get us some beer and hot wings and we'll do it!!" So hopefully all this may cost me is what four guys can consume in beer and hot wings, the replacement parts and a entire Sunday spent cleaning them out of my house!
Who knows- I may get under there too and help, I'm not afraid to get my hands dirty............but if I break a nail their on their own!