So...the day that the new owner came over to pick up the car a completely new issue popped up with the transmission (Murphy's law?). This only happens when manually shifting the tranny. When going to 4th, it stays in third and the only way to get it to go into 4th is to turn off the car and keep it in 4th. It will also go from 4th to Neutral. I looked at the troubleshooting guide but most of the suggestions there are presuming that you are in in D all the time. The closest I could find would seem to be the valve body. To me it seems almost as if there is some kind of position sensor that isn't working correctly. But, why only when shifting manually? TIA and sorry if this has been discussed but I didn't see the title as being the same.