I previously asked about tires/wheels as my 940 has 205/65R15s on it. I finally got out my wife GPS and drove around testing and, darned if my speedo isn't spot on! (Speedometer - not the thing I was wearing while driving :)

I would have expected my odometer and speedometer to be reading low (says 70 when doing 75, etc).

Is my thinking wrong? What might be the cause of this accuracy? Do I have to now spend more money on tires to keep the speedo working (since this is "my son's car" if I ever let him have it)?

Transmission Issues: Kickdown, overdrive and jerking.

I think I can follow the FAQ and get the kickdown sorted out, but the other two issues I need a couple of hints.

Overdrive works. Is the little button at the back of the shifter nob supposed to disable OD? If that is not working is it possibly something simple like a burned out wire or do I have to take lots of stuff apart?

My biggest concern, saved for last, is that the car thumbs pretty hard when I go from Park to D or R or from R to D.

I do not know when the tranny was serviced last (if ever). I am thinking about going the Auto-Rx route but want to know if there are any mechanical things I should check first.

Thanks