2007 trailblazer 4.2 l6..4L60e swap to 4l80e

[som3astar]

Hello
I need some help with my tranny i changed a new transmission 4l80e and the original one is 4l60e i did the wirings but still need to change in ecu.but still car stuck in 1st gear
I paid hptuner to try to do changes with it . But have no option to do that
Need some help with that ..
Paid help or free help or someone to point me in the right direction
Thank u all

[ScarabEpic22]

I've not heard of anyone swapping an 80E into a non-V8 TrailBlazer until now, so seems like a cool project!

There is no transmission segment (nor OS) compatible with your 2007 P12 PCM that will run a 4L80E, the P12 was only used with the 4L60E-family and manual transmissions. If you had an 08-09, this would be easy as there are compatible TCM OS' available. Upgrading to an 08 ECM+TCM isn't possible as the crank/cam reluctors on the I6s are different between 07 and 08.

You will need to either:
1) Repin the harness and add relays to run the 80E on the 60E transmission segment.
2) Purchase a relay harness (not a normal swap harness) that is designed to run a 80e on 60e programming. Multiple vendors provide them, I know PCMofNC, TunedbyFrost, and others make them.

Tire size/shift points/pressures/so forth can be done using HPTuners.

You may also need to retune for the 80e ratios, it appears these are not mapped in the 07 TrailBlazer P12 file I have that uses OS 12627885. This may cause Traction Control, StabiliTrak, and/or ABS issues.