Thanks for the replies.
All the tires are the same size, they were all replaced together 20,000 miles ago and have been rotated. One side lost about 10lbs of pressure and I don't know how long it was like that before I noticed it. That's what put the nail in the coffin on the coupling I'm sure. It's better with the tires properly inflated but defiantly not 100%.
No it isn't completely shot yet, it's just starting to go. As for junkyard parts it's pretty much out of the question. Junkyards around here think parts are made of solid gold. They want $2,000 for any transmission. I could buy another good running car for that.
I'm debating getting the part from the dealer and changing it out if it's possible to do it. The cars worth about two grand, I need the coupling, timing belts, a clutch, an 02 sensor, possibly a cat and I need to repair some rust. When a $2,000 car needs $1,000 worth of parts it might be time for it to retire.