2003 lq4 with th400 transmission

[Fast355]

Not sure I'm understanding the relevance of this. The bit is still there in in HP Tuners and has for the most part always has been. I'm stating that it is widely accepted by the hundreds of people that use that product regularly which includes me, all agree that is is there for identification purposes only and does not change a auto calibration to a manual. You have to either segment swap the calibration or start with a manual file. If it did I doubt GM engineering would populate the manual transmission calibrations with different segments. They would just flip the switch. I'm not here to argue with anyone, I'm just stating what I know and a very large tuning community on HP Tuners forum knows to be a fact.

I have a 1 meg 05 or 06 L31/5spd Mexican GMT800 file that had all the automatic shift tables populated. I did swap the 4L80E segments into that calibration to run the 4L85E in my L31 van when I did that swap.

That setting is in fact a calibration switch. I have used it in several non computer controlled automatic calibration swaps. Never have tried it with a manual so cannot comment there. I can tell you from experience swapping from a 4L80E to a TH400 in my buddies 6.0L swapped GMT400 running on a 2002 0411 tune, I flipped that setting, did a rewrite all and all the codes related to the 4L80E being unplugged went away and the truck drives flawlessly. The next day that truck went into the 12s in bad weather conditions in Houston at the Cleetus and Cars event. 2-3 tenths quicker than it ever ran.

I just looked at an 05 6.0L/4L80E 2500 truck tune and it appears the manual trans settings are in fact there as well in the tune.