Glad to hear you found the cause. I've never come across that before... so I've learned something new today. :cheers:
Correction: went for a rip earlier and the dually was softer than I remembered so I shortened the min shift time to .3. My guess is that it needs to learn to the quicker times, but I suspect there's a way to land the base pressure so that less correction is required for shorter shift times. What might I need to log for that and how would I plot it? It's something I've been pondering for a bit. If it's the way ahead, then I have 3 trucks to apply it to.
That's something which I can't help you with... hopefully someone else will be able to help. What I do is leave the line pressures stock and give it some more room to learn by changing {D1101}, {D1102}, {D1103}, {D1107}. There probably is a way to adjust base line pressures, but I would never be comfortable doing that.
If I had corrected some of the known wrongs in my tune in conjunction with the throttle body swap and done a flash at the same time I would have not known it was a factor either (kinda odd that I didn't as I tend to flash something new into the truck most days). Made for a slower haul as I was afraid to give the thing any throttle with the trailer to try and keep the shifts as soft as possible but now that it's healthy again I can concentrate on some of the things you and Joecar have highlighted. The real prize was taking this back into posession.
Attachment 21972
Attachment 21971
Well there's another reason to fear base pressures as I currently do. Seems these tables would also need to be smartly coordinated with a shift in base pressure. Definitely going to poke around an 8.1 4L80E tune to scout for significant differences.
Hooked up the trailer again and I must say it is much better than last weekend even if you ignore the smoother shifting. Deleting the kickdown has the transmission downshifting in a far more intuitive manner and having the TPS read properly I'm sure is also helping. I didn't find myself cursing the truck, just needs more power now. Shifts aren't even really that firm, but they are quicker now. I feel I now have the 90% solution as far as drivability, I can't imagine being stuck with a stock tune on one of these things with an automatic.