We recently purchased a 98.5 dodge 2500 cummins automatic. Here is the problem, when you hit about 45 it shifts up then down then up then down and all over. holy cow. I remember many years ago i drove a new one and it did the same thing. i was unimpressed. this seems to be worse. it continues even as you increase speed. does anyone know if one of the programmer units will fix this? is this a common problem on the automatics?