Dodge Neon Transmission won't shift

My son has/ i paid for it a 2002 neon, It was down shifting hard real bad, took it to a tranny shop and they flashed the eprom and reprogramed the shift points, we drained tranny fluid and installed a new filter, synthic ATF 4, used a bottle of Lucas oil tranny stuff, has 125,000 on it now and not had anymore issues, this all happened at 78,000. I think you will have to take it to a tranny shop IMO. Hope that helps.