I have an extended length 3.4L 2004 Pontiac Montana. The speedometer cluster has been going bad for a little over a year now. First it was the temp gage acting like it was off calibration. It would show as if the radiator fluid temp was off the chart with the needlt pegging. Then it would go back to working right for a few days. A few months ago, the fuel gage started doing the same thing. Now it always shows past full. We had the van checked at the 100,000 mile service last summer at the dealer and we were told that the speedometer cluster had a short. My question is first, does this sound reasonable with the symptons and second, What is involved with chaging out the speedometer cluster. I have locate a used cluster that is a 2003. Thanks for your help.