Thanks for the data, RLeo. I thought that the speedo gears in the instrument cluster correspond to the diff, and that all the speed gears in the trans are reading exit rpm. Ergo, diff and cluster stay same, readings stay same.
That said, if the evidence is to the contrary, then maybe I am wrong.
Which cars got the 2.88 rear?
I'll have to do a GPS check. I am not worried too much about an inaccurate speedo, at least at that ratio. If what you are saying is true, then manual trans may differ as well, no? Trying to figure out how to match my hybridized car may be too much!
If it is reading high, my wife will like that. I have a heavy foot.