SL W129 320 (1994) goes too high

Dear Foren reader, I would be very pleased with suggestions regarding the following problem: My SL 320, EZ 1994, turns too high. Idle speed is fine (approx. 700), the problem occurs only when driving. At approx. 200 km/h the rev indicator intervenes. Normally it should do this only at 250 km/h. At 100 km/h it has a terrible 3000 rpm. Much too high! I had the transmission oil changed. It switches softly. In advance it has ticked off and on while switching (on a When I switched to the sport mode, it went again. If I switch by hand (you can also switch to the sweetheart), he also switches to the fourth (it has only four gears, right?). It works everything, but does not change that he already has 3000 rpm at 100 km/h. Can someone explain to me what causes this could have? Call me a good side to the technique of the automatic transmission if necessary? My lay-like gut feeling sa gt, it is an electronic problem. Thank you very much in advance Djinnious * who is afraid of an expensive repair*