Hello I never liked Fords, but I stupidly decided to go buy one. It was a $400 "mechanic's special". It runs great, has a 7.3 powerstroke diesel, crew cab dually 2wd. It only had reverse when I bought it, so I pulled the trans fully rebuilt it myself. The problem was the drive clutch pack was completely toasted. I also replaced the solenoid pack bc I damaged the plug and it was recommended to be replaced anyway. I filled it full of 16 quarts of Valvoline DEX/MERC. And it went into all gears and seemed to work PERFECTLY!!! I was excited and proud of myself for fixing it. I hadn't driven it on the road until today, and it WILL NOT shift out of 1st gear. I could only get it to shift by flooring it and taking foot of the pedal after it shifted, otherwise it would downshift back to 1st. This was a a whopping 3100rpm... 2nd to 3rd seems to work fine... If you shift it manually from 1st to 2nd then back to D it will sometimes downshift back to 1st, other times it will hit 3rd... I checked fuses, fluids, plugs, and everything I can think of... No codes either. I am stumped, and pissed. I now hate that stupid truck. PLEASE help. I am no Ford expert and no transmission expert either. I know these are electronically shifting so is there some computer that could be bad??