Regarding the shifts, it is unclear (to me anyway) whether he is getting the shifts at 2000 rpm under light pedal pressure AND heavy, or just light. 2000 rpm sounds about right under light accel, but I also see shifts around 4500rpm when zooming.

The "S" on the shift console stands for 'slope', and is both for climbing one and descending one, it was designed to and does work great as an engine brake in the mountains and saves front brakes from overheating.

I think a definitive answer from smartin as to the shift points under heavy accel would help everyone trying to assist.

__________________
1982 Mercedes-Benz 300CD
1982 Mercedes-Benz 240D - stick