I know there's threads. I can't find them! I bought the truck with most of the stuff done to it I have all receipts and where it was done and what not. It has a 500+ HP Suncost converter and clutch pack kit installed in trans. Trans parts prolly have around 25-30k miles on them now. Ive had this issue for a year now but due to fuel cost ive been driving beater. It has a hard shift problem from 2-3 and sometimes takes longer to switch gear (at lower speeds). If I am at a stop and take off quick and keep going to 5th gear it will shift like a boss but city or slower driving it wants to almost hesitate. Ive switched the tunes from a good but "generic" tune to a EzLynk with my shop going through a company and trying to dial it in. Suncost says they've heard of the problem and want you to leave the TSM in its stock tune. Ive replaced solenoids, then I replaced the whole damn Valve Body. Same thing. Besides the tune does anyone know or could help me figure this stumper out?

 

I'm no expert but obviously you have a deleted truck. What year truck and mileage?

That adds a layer of confusion to the problem because you are not running stock trans tuning. It could very well be the aftermarket trans tune causing the problems. Seems like you're throwing parts at it, so while it can't be ruled out that it's not the trans itself, tuning would be the place to look at. Seems the previous owner was trying to fix the same problem and then dumped the truck.

I searched here in the forum with these terms: 6r140 shifting problems

and got 28 results.

 

Yes sorry it is a 2011 f250SD 6.7 super crew lariat

 

reflash the TCM to ford's programming. Dial the HP/TQ down to stock power levels and see if that helps.