Gear problems again

Hello together, first of all I would like to say how great you find this forum. Were already many solutions for me, unfortunately not the right one yet. So, now to my problem. Drive an S600 year 1991. For about half a year I have the problem, which the gearbox has different symptoms. At normal start-up it switches down at about 30 kmh into the first gear and then immediately up again. At kick down from the stand, the problem does not occur. In addition, it is so, if I At about 80 kmh the speed of the kickdown wants to do, the speed goes into the rotary fence limiter, as if it were switching into a too low gear. These problems do not always occur. Sometimes the gearbox also switches very delayed and slow. The car was in a MB “specialist workshop”. This swallowed up to today approx. 800€. Previously the inspections were made fairly. MB has probably changed pretty much everything that came to mind. Among other things, the LMM, both Kat. I checked the switch “B” myself – it’s ok. The engine is running like one now. For example, if you do kickdown on the highway from 130 kmh, it will mask up without any problems. I have the feeling that he has any problems with the first gear. I don’t know any more about that. Would be a great Christmas present if someone had some solutions and I didn’t have to give up my baby. ank in advance and Merry Christmas greeting Markus