TBSS 4l80e swap help

[Tonyorlo]

I have an 07 TBSS, the body and frame aren?t in great condition, I have an 08 Trailblazer that is spotless. I am going to swap the drivetrain and all SS related parts to it. I?m also dropping in a 4l80e and a transfer case from an Escalade.

I have completed a few Gen 3 LS swaps, but never one in a Gen 4 (I assume this is considered Gen 4 having an E67 pcm?). Reading through the manuals in the segment swap section, it doesn?t go into great detail. Just that the IDs need to match. Well I have the pcm from the donor trans vehicle. I also have a few spare E67 pcms, I would like to write this all on a spare so I can leave the original pcm for the TBSS as is.

Long story short, how would you folks suggest I do this? I?ve been searching and reading through past threads but still have a lot of questions. I apologize if this is common knowledge, this is my first project like this using HPtuners. I?ve always used PCMhammer and TunerPro, but I feel more comfortable using HPtuners on this one.

Thanks for any advice!

[blindsquirrel]

Since Gen 4s have separate ECMs and TCMs, it's the TCM OS that you need to match to do a segment swap. The ECM doesn't get changed (and doesn't have to match anything in the swap-from file).

Often times it is much less aggravation to just use the adapter harness and keep the existing 4L60 TCM & tune settings (the harness makes all the changes for you):
https://www.pcmofnc.com/product/pcm-...rsion-harness/

[Alvin]

We also sell a 4l80 trans mount for the Trailblazers. Might be useful to you.

[Tonyorlo]

That?s a great option. I am going to really considering going that route being this is for my wife?s daily (KISS!). From what I?ve read, the TBSS and up to 08 I6 Trail Blazers use the pcm to control the trans? I didn?t have a separate TCM by the master cyl.

If I decide to segment swap it, I assume I?ll need to find a bin file with the same OS as mine? Which may be tough because I believe 4l80s weren?t used in 07. I would like to have access to the pcm for future modifications so I figured this would be a good time to get the credits. I?m not rulling out the harness though.

Thanks for the replies! I have my trans in already Alvin, but it looks like you may have other parts I?m after. Thanks!

[blindsquirrel]

There are non-TBSS platforms (2500 trucks/Suburban) with the same TCM OS. The ECM OS doesn't have to match. It's OK if the donor file for transmission segments is even a different ECM family (E38 vs E67).

The trick with the TBSS/GMT360s and segment swaps is, it's real common for the full-size truck transmission OS to not operate things like the PRNDL, and other similar annoyances. The harness avoids all that. There is a combination of segments known to work for the 2006, using segments from two different platforms, but I don't know that any options like that exist for the 2007/2008/2009. The harness is the Easy Button.

It will get a lot easier to give you answers that are more than just vague guesses if you post your *.hpt file.

[Tonyorlo]

07 TBSS MINE.hpt

It took a few tries to completely upload it. This should be both engine and trans files. Im still considering the harness, just want a better understanding of this.

Thanks!

[blindsquirrel]

There isn't a 4L80 TCM OS with 24238660, and using a complete TCM OS from the big trucks will leave you with stuff that doesn't work right. Dig in and see if you're willing to work hard to build the knowledge you would need to make this work some other way besides just buying the harness:
https://html.duckduckgo.com/html/?q=...s.com+24238660

Keep in mind that it's a real possibility that you might go through months of study and experimentation and at the end of your journey, turns out, it may not be possible at all for anyone of any skill level to make it work in that year model with a real 80E OS, because there isn't one to borrow pieces from, and writing your own OS from scratch is probably not on the table.

[Tonyorlo]

Well apparently I have not done a great job at searching, and I?d venture to say your tired of seeing the same question asked over and over again because you?ve chimed in on all those threads lol. I see one fellow had luck segment swapping, I am going to dig into what he has done and try to understand it. You replied to his post with a breakdown of what he did, so that will help me a lot. Like I mentioned, I need this one to work without much stress. So the pcmofnc harness will probably be in my future.

I don?t have the knowledge or time to piece together an OS to make it work, Atleast not for this project. I?d love to be able to in the future though. I?ll keep researching to for now?.

Thanks for the help!

[Alvin]

Leftcoast32 sells a 4l80 swap package with a different OS. There is a chance maybe he will just sell you the TCM file/tune.

I made my harness just to make everything simple. Not everything will have a 4l80 file or segment to swap from.. like 98 corvettes/F-body for instance. There should be solid TCM files for 06-07 out there. 08+ I'm not sure.

[blindsquirrel]

Are you planning to use the 2007 ECM in the 2008 non-SS TB? Or 2008 ECM?

[Tonyorlo]

The harness you made Alvin is tough to beat. It seems pretty straightforward to me. I may reach out to Leftcoast and see if he would sell me the file, I cant blame them if they wouldn't want to do that though. I do think this trailblazer may have your electric fan kit on it though, it sure looks like the one on your site.

I'm green to this oviously, but I haven't had much luck in the repository. Every file that Ive downloaded doesn't seem to have the transmission segments when trying to compare files. They are all greyed out with no info in them.

Blindsquirrel, yes I plan to use the 07 TBSS ECM in the 08 non SS. Which isn't making this any easier I'm sure. The 08 had secondary air injection, which the SS doesn't have, and it was 4WD. So I have those few things on the chassis harness that I will have to deal with.

[Tonyorlo]

I came across this in the repository. Its labeled to be a tune from an 08 express van with a 4.8 and 4l80e. Its from an E38 pcm, does that make it more likely to be compatible with my E67? The tune from the 2003 donor 4l80e trucks P59 pcm is no help with this is it?

[blindsquirrel]

The ECM does not matter, the TCM operating system ID number has to match before the Segment Swapper will let you do anything. A T43/6 speed will not have the same ID number as anything with a T42. Something with a PCM doesn't have a TCM, so it will never have the same ID number. Only rarely will you find anything that's a different year but with the same ID number.

If you use the Express 24239927 4L80 file (either the full TCM file or by segment swapping) in a TBSS or other GMT360, you will end up with a PRNDL that stays in 'P' all the time, among other problems that can't be solved without different segments.

Maybe (maybe!), the 4L80 segments,base OS that works in the 2006/E40 will also work with 2007/E67, from something Alvin said. I could have misunderstood that. But the truck's hardware and the way everything talks to each other did not change from 2006 to 2007. Everything did change though in later years.

[Tonyorlo]

I did find an 07 tune from a suburban that has a T42, but the OS is different.

I hate to be a quitter, but waaayyy smarter minds have thought this out and did not succeed. If this was a project car that wasn't my wife daily then I would maybe attempt it. Same hardware I know, but I searched around of EFI Lives forums and they are in the same boat. Its a shame I couldn't run a "external" tcm to handle it.

Ill be placing an order for a harness here in the next week or so Alvin.

Thanks for all the help!

[blindsquirrel]

You do have an 'external TCM', you have a T42. It's mounted on the other side of the plastic bracket from the ECM down on the driver's side frame rail, right below the battery.

This is the file used for the 2006, with the right mix of segments to make everything work - in a 2006. Unknown if it really would work in a 2007:
T42-only 2006 GMT360 4L80E 24235341-24232586-24238958-24233116.hpt

[blindsquirrel]

20250411_094927.jpg

[Alvin]

You do have an 'external TCM', you have a T42. It's mounted on the other side of the plastic bracket from the ECM down on the driver's side frame rail, right below the battery.

This is the file used for the 2006, with the right mix of segments to make everything work - in a 2006. Unknown if it really would work in a 2007:
T42-only 2006 GMT360 4L80E 24235341-24232586-24238958-24233116.hpt

If it works in a 06 it should work in a 07

[Tonyorlo]

When I get everything switched over I will try that file, worst case I have to go back to stock and get the harness adapter. Do you have them built Alvin, or are they built as the orders come in?

Edit: My OS Id doesn't match the OS Id on that tune. So I wont be able to segment swap it right?

[blindsquirrel]

07 TBSS MINE 2006 4L80 TCM.hpt

That's your already-licensed file with the TCM removed & replaced with the other one. Changing the TCM OS or the physical TCM module does not break the license.

Note that is only a base file with the right segments to make everything work, it is not a 'tune' that's meant to be correct for anything. Shift scheduling & pressures and everything else will need to be tuned.

[Tonyorlo]

Awesome! Thank you squirrel! Turing a trans is very new to me, I just know some terminology from playing on HPtuners. Is it a dumb idea to think I could use the stock 03 files as a guide to tune?

Also, I have the LQ4 and complete harness from the donor of the 4l80. Would going to the lq4 p59 and harness be a stupid thought?