buy this months Family Handyman, it is the last issue and has the index of all previous handyman topics by alphabetic order. Look up which issue has all the information concerning this linkage, then check it out in the library or on microfish.
I believe, although I have never had any encounters with this linkage, that you can fix this without removing the tub, this has to happen to many people and for the tub to be removed is just too much.
Installing a tub on a slab is much easier that on a pier and beam or on a second floor. Getting the old tub out might be harder than putting a new one in. You can possibly use the old framing to cradle the new if its the same configuration. The tilt and the cradle and the critical pipe line up is the tough area. You will most likely need a plumber anyway for some of the work.