Well, the title says it all, the truck is a 2004.5 6.0 powerstroke with a 2005 transmission. The transmission is having an odd problem that no one has an answer to. I live in Indiana and not a single diesel shop or ford dealer around has a clue to why it does this. No matter what, everytime i change tunes, it being stock, performance canned on sct, or my custom tunes the trucks transmission slams the 3 to 5 shift, ive tried the relearn procedure multiple times, the only way it goes away is to drive it easy, after you let it slam that shift a few times, it starts to clear up, but isnt truly gone for like 30 to 40 miles. I personal change tunes often and this is getting annoying haha, i just bought this truck and i never had this problem on my other 6.0 i had before it. The nearest diesel shop told me the pervious owner replaced the transmission and it did the same thing with the old tranny as well. Im at a lose, and if someone could maybe shed some light, i would very much appreciate it! Thanks in advance!!