L92 4L80 Communication Issues

[jon9116]

Howdy

First time poster here. Ill preface by saying Im not a tuner. I do my due diligence and research before asking questions however.

Ive recently swapped an 07 L92 (no dod/afm) into my 86 C10. My tuner used an E38 with OS12614088 as a base and changed the parameters where needed. I believe thats from an 07 LY6. He used OS24235341 for the T42 which is also a 2007 file.

Im throwing codes P0700, P0787, P2769
And my transmission wont shift out of second.

Would using a TCM file from an 08/09 express van work? Particularly OS24243356? Any issues with running an 07 E38 OS with an 08/09 T42 OS?

[Jon S.]

If you are seeing all of those DTCs, then the T42 TCM has likely been programmed as a 4L65 / 4L70, rather than a 4L80.

I would recommend using 2008 model OS in both controllers.

The E38 ECM would be 12617631 (from a 2008 L92 - adjusted as necessary for the camshaft change).

The T42 TCM would be 24239927 (from a 2008 Express van with a 4L80).

[jon9116]

Ended up getting an 08 express van TCM and had my buddy adjust my gear ratio/tire size. VSS is on point and I show no DTCs.

The problem now is it shifts great 1-3 but I have no OD. My buddy plugged in his scanner. The scanner shows it starts off in 1st, goes to 2nd and then the tcm thinks its in 3rd when it's about to physically shift into 2nd gear and it?ll show 4th right before trans physically shifts to 3rd. We couldn?t command it into 4th because it already thinks it?s there. Any ideas?

[jon9116]

bump. Same issue