I think Mercedes set an overspeed governor in all their cars so that you couldn't exceed the maximum engine speed when you are in any particular gear. My SDL (Believe it or not)is governed between 5200 - 5500. Not bad rev range for an oil-burner!
The marks on the speedometer
one mark 'first to second' *
two marks 'second to third' **
three marks 'third to fourth' ***
Third gear should take you up to 75mph and bounce off redline. Engine might kick back if you're accelerating too fast.
A little trick, of course, for all second gear starting Benz's. You can start out in first if you shift to '2' and back into 'D'. Or in the V8's, shift to 'B' and back.
1987 300SDL (324000)
1986 Porsche 951 (944 Turbo) (166000)
1978 Porsche 924 (99000)
1996 Nissan Pathfinder R50 (201000)