I got a new coupling, installed it, and I am good to go for my trip tomorrow. For those of you in Michigan or the Midwest you should check out Slicks Salvage.
http://www.slickssalvage.com/They gave me a great price on a low mileage rear wheel coupling and they have a great selection of other parts. I ended up buying something for my KLR as well. On the way out the door I was asked what size t shirt I wear. When I answered they gave me a Slicks Salvage t shirt for free, and it is a nice looking shirt. The guy that runs the place also rides a C10.