P.S. re the 1.27 correction factor on the odometer and 1.15 on the speedometer: flow of traffic seemed to support the 1.15 multiplier for the speed, and we double-checked the odometer check range with another longer run in Texas, in which I watched until the odometer rolled over exactly at a mile marker, then waited until it rolled over almost exactly at another mile more than 10 miles down the road. Both came up just about 1.27. Maybe a change of rear end ratios, but why at less than 40,000 miles unless someone let the chuck run dry and replaced it? It's quiet as a mouse now.