I have been looking for the changes GM makes to the TCM when you bring it in to fix the issue with the transmissions cooking themselves when operating at -40 conditions. I cannot seem to find out the changes they make in the TCM only that a reflash is needed to keep this from happening.

The reason im asking is because I am having issues with a truck that has has issues ever since this flash. I am trying to go through it and figure out why it is shifting erratically and not locking the TCC all the time.

I stumbled across these values, which to me look out of place.

D1570 Mod main pressure Gsol enable low temp --- - MINE -10C
D1780 Mod main pressure Gsol disable low temp ---- MINE 45C
D1581 Mod main pressure Gsol disable high temp ---- MINE -15C
D1582 Mod main pressure Gsol enable low temp ---- MINE 43C

Ive done some researching and found that this Gsol controls the TCC. And if thats the case these numbers will cause it to do funny things as they dont seem to make sense.

Its saying to enable it at a low temp of -10C, but yet disable it at -15C.



Thanks


Mitch

I have been looking for the changes GM makes to the TCM when you bring it in to fix the issue with the transmissions cooking themselves when operating at -40 conditions. I cannot seem to find out the changes they make in the TCM only that a reflash is needed to keep this from happening.

The reason im asking is because I am having issues with a truck that has has issues ever since this flash. I am trying to go through it and figure out why it is shifting erratically and not locking the TCC all the time.

I stumbled across these values, which to me look out of place.

D1570 Mod main pressure Gsol enable low temp --- - MINE -10C
D1780 Mod main pressure Gsol disable low temp ---- MINE 45C
D1581 Mod main pressure Gsol disable high temp ---- MINE -15C
D1582 Mod main pressure Gsol enable low temp ---- MINE 43C

Ive done some researching and found that this Gsol controls the TCC. And if thats the case these numbers will cause it to do funny things as they dont seem to make sense.

Its saying to enable it at a low temp of -10C, but yet disable it at -15C.



Thanks


Mitch

What year and model is your truck and engine RPO? (I know its not the '01 in your sig.)

Sorry... its a 07 LBZ...

TCM OS 25941752

I would start a thread in Custom Tuning Software/ EFILive and see if some one there had the cold weather TCM update done. You then could compare there files with yours. I take it these files are for lock/unlock the TC.

Its saying to enable it at a low temp of -10C, but yet disable it at -15C
I know nothing about EFILive or the Allison but just looking at those numbers they make sence. You don't want your TC locked at -15c but at -10c its ok to have it locked.