Why is my odomoter on my 65 going bananas on me? It reads way to many miles based on comparison with my GPS. Now the speedo works great, very close to what the GPS said. I mean the odo is reading like double the miles. But not all the time. One of the comparisons was only off by 5 miles (out of 170 or so). Is it terminal or is there a cure? mikeH SE VA