I have bump shift down between 4 and 3 gear. 2003 Chrysler town and country. I';ve change oil filter, and prob?

Did you put the right fluid back in. It takes chrysler atf+4 and only that not dextron 4 or anything else. If that's whats in there, then there are several updates for the TCM(trans control module) Can only be done at the dealer and also tel them to Quick learn it.