That was exactly what the problem was. The computer system (center of console) had been changed from miles to meters and as soon as I changed it back to miles, the display started acting the way I expected to again.
I am embarassed. I did take it to the dealer and they thought it might be the control module. They ordered one and when they installed it, nothing changed. They spent half a day on the phone with Detroit trying to figure this out and finally gave up and said they were stumped. As soon as I tried your solution, everything reverted back to normal. I e-mailed the dealer to let him know the problem was fixed. I would like to hear the discussion between the service manager, mechanics and the engineers in Detroit when they hear it was just a configure problem and not a hardware problem. Thanks again for the explanation and solution.