In regard to Truckernix question on how the PG shifted I would have to disagree that it took off in high range. As I remember them they started in the low range and shifted to the high range as would a F*&dOmatic or Hydramatic. You could feel the shift point. The L position was to keep it in the lower range and allowed manual shift to the high gear. It could also be used as a grade retarder.
I think the info you got was describing how a TurboGlide worked. It had only one range and a Gr which was used as grade retard. There was no discernable shift point in a TG which was the same as a Dynaflow. The TG was total junk and only lasted for a couple of years. People didn't trust them and with good reason.
Heres hoping all are having a great Thanksgiving day.
