Hello. I don't know too much about cars but my husband does. We have a 92 lumina and a 95 lumina. We also had another 92 lumina but got in to an accident. With the other 92 we had the same problem with the car slipping out of gear at stop signs and we would do the same put it N then it was fine. Both of the luminas we have now did the same things before we bought them now the bands in the tranny's are shot. Sorry to tell you this but from expeirience you are going to need a new tranny in the near future. DO NOT use the lucas tranny oil syuff. It will help for a few weeks but I think it does more damage than good. I just think luminas are not able to handle being ragged on it really hurts the trannys. My husband is at work but if you have any questions he would be able to help.