GMPP 570hp LS7 with 6L80-E

[rabbs88]

Hey guys, I just got brought into a ground up build by a family member after realizing they're in over their head a bit. The build is a 1971 Blazer with a GMPP 427/570hp LS7 and a 6L80-E all purchased brand new from GM (You may already see where I'm going with this). I just finished wiring the engine harness (E67 and GM harness p/n 19420000) and went to read the ECU and of lo and behold, I couldn't read the T43 out of the trans. I just read the E67 to find that GM sent it with a manual trans OS# 12638778. Not surprising as no LS7 cars had autos, however, this is what I've been presented with.

So to get this to work properly does anyone know what needs to be done? Would it be as simple as using a tech2 to flash an auto e67 OS onto it and tune from there? Any help is appreciated!

[radrace19]

Hey guys, I just got brought into a ground up build by a family member after realizing they're in over their head a bit. The build is a 1971 Blazer with a GMPP 427/570hp LS7 and a 6L80-E all purchased brand new from GM (You may already see where I'm going with this). I just finished wiring the engine harness (E67 and GM harness p/n 19420000) and went to read the ECU and of lo and behold, I couldn't read the T43 out of the trans. I just read the E67 to find that GM sent it with a manual trans OS# 12638778. Not surprising as no LS7 cars had autos, however, this is what I've been presented with.

So to get this to work properly does anyone know what needs to be done? Would it be as simple as using a tech2 to flash an auto e67 OS onto it and tune from there? Any help is appreciated!

The TCM has a custom calibration programmed into it, and the ECM must be programmed as a manual to work correctly together. Don't change that setting.
Don't overwrite the ECM calibration with a stock LS7 file.

To calibrate the TCM use the cable and software that would have come with the transmission.

[Alvin]

I've modified them before with Hptuners but they don't work like a factory controller. The TCC lockup will be abrupt and you can't do much about it. If you change TM stuff like you normally would it will cause other issues.

Using Hptuners to dial in shift points don't seem to be a problem.

[rabbs88]

I didn't know there should be a cable and software for the TCM. I'll have to take a look for it. That would be awesome if it's that simple.

Alvin, that's interesting that they don't work like a factory controller. You would think they would be the same? Would it be beneficial or even work if I got a factory E67 and flashed it with a vin that had an OS that has a 6L80 from the factory like an 09 XLR or something? It would be nice to just be able to read and tune both things from the editor instead of different software I'm not used to

[rabbs88]

radrace19, I found the software and cable for the trans. That should make life a whole lot easier. Thanks for the help!