Have a new Omi A and a problem

Hello everyone, after the bad luck with my old Omi has not been torn down I have now got a “new” one. Nen 2.0 Automatik Caravan, year 1989 and original 56000 km ;-)) Since I have never driven automatic immediately raises a problem. Partially when I start the control light “S in the gear” flashes up in the cockpit. If that is so then it does not pull right in the D-level. If I turn off the engine and restart then it is mostly gone, whereby I tomorrow We have made gear oil changes and filled in about 3.5 l of new gear oil. Would be nice if someone knows their advice. LG the Citymaus