Originally Posted by mrcoolgli

Thanks for the reply. If I program the ECU with Extream/Performance/Street/Tow and leave the TCU stock I have no problems. I can't put any tune on the TCU without the slaming coming back. Either way, I traded in the truck on new years eve so I don't have to deal with it.

Originally Posted by TIRE FRYER

ETKMS, I just went from the 210 tune to the 210 tow tune because I had to tow a 30ft camper trailer and I had the same hard shift issue. It took about a week of driving for the shifting to re-learn and I seem to like that tune now. It has become a crisp shift that is not at all annoying. In the beginning though, I thought my trans was gonna fall out of the truck.

Originally Posted by mrcoolgli

I replaced it with a 2013 F150 King Ranch with the 5.0 v8. No it's not an F250 but it's very nice. I got good value for my F250. I don't tow much so not a big deal.

As for the shifting.. If I even a little got into it the shift would slam into the 3rd gear and pop out. If I continued to accelerate it would keep slaming. HARD. After two or three tries it would kick on the wrench and go into limp mode. So something was not right. I tried driving it very very gently for a day or two hoping it would re-learn but it was just un-drivable. Stock it had no problems.

Originally Posted by ETKMS

LOL, well the title says it all. Not sure the best thing to call it. about 2k miles ago I finally did the Spartan and DPF/Cat delete, trucks has been running good, I keep it on 210 all the time, I never even floored it! I just did it to get rid of the DPF. I was approaching a red light, so I took my foot off the accelerator to coast, then the light tuned green so I press down on the accelerator and I was not going anywhere? I press down again, nothing, I heard the engine rev, and my music was a bit loud, I turned it down, pressed on it 2 times quickly, then it finally bucked forward and drove fine.... It feels fine now, it shifts smooth, and all is well. I remember before I did the spartan, I think i caught the tranny do the same thing in a similar situation, only it got power right away but the truck REALLY bucked forward HARD and, and i almost felt axle hop? I cannot get it to really happen again, but I am wondering what some thoughts are on this? what can it be possibly?

Thanks!!

Originally Posted by SANDDEMON08

This issue is pertty comin with the more aggresive spartan tuning or other tuning that adjust's both the PCM and TCM together, i have had the same issue's u have stated with no realy problems as a result of it. Matt with spartan has stated it has to do with the hardware its an underling issue and it becomes more rellivent or magnified with more aggesive tunes due to the higher trans lines pressure to balance the higher HP demands. There are many including myself that run an additional quart of fluid which helps with this issue ( I really dont know why) with no venting issues unless the trans is overfilled to begin with and u add an additional quart. The trans should not read at the full line when cold, it should be a little below and will expand to no higher then the full line when at operating temps 175 degrees or more.