I called the guy from the website I listed above and he had some interesting ideas that I didn't think of. I was going to order up a 90" custom cable. He told me that was expensive and was a waste of money. He gave me a couple of suggestions. He said sometimes if you have enough bends in the cable, it can cause the inner cable to shorten up and not make full contact with the speedo. But, now that I think of it, that end at the speedo has that little brass bushing on it that keeps the inner cable from receding into the outer sheath. So, I'll have to check the transfer case end when the upper is connected and make sure that there is enough inner cable protruding out to make contact with the connector.
Secondly, he suggested that I pull off the lower and hook a drill up to the inner cable. If I run the drill, and the speedo still bounces, then the speedo is shot. If the speedo works fine, then the gear in the transfer case could be shot. I'm hoping it is the plastic gear in the transfer case. That would be an easier swap than the speedo, which is now behind a full roll cage. DrEmu, I'll let you know if I need one, thanks.