6l80e on older PCM ('03 Silverado)

Hey guys/gals,

It would appear I am trying to do (once again) the impossible....I've done some initial searching all over the internet, and I have found numerous threads (from numerous forums) with people going FROM a 6l80e to 4l60e/4l80e. I've found numerous threads on the methods, and even a piece of hardware that lets you go from the 58x to 24x crank setup...

However,I want to go the other direction.. I want to build an auto-crosser out of an '03 Silverado RCSB truck, the truck will have AWD and R-comps so it is not going to have traction issues, for this reason the 6L80e is very attractive to me (that, and I already own the Trans and AWD T-case). I am not able to find exactly what I am looking for to complete the trans install.

So onto my dilemma:
Is anyone aware of what exactly would be required to allow the use of the '03 24x PCM with the 6l80e transmission. I know the newer stuff has its own controller, but I believe they both still talk to each other.

Any help in advance is greatly appreciated.

Id love to say it'll be easy, but AFAIK its going to involve at minimum yanking the engine and swapping to the Gen IV 58x/4x reluctor setup. Once your Gen III is 58x, then you can use an E67 or E38 to run it and control the 6L80E.

The only standalone Ive seen is the MAST setup, but it has an ECM as well. You cant really run these new transmissions without feeding them a proper TQ signal from the ECM, they wont shift correctly and if they do initially, they wont for long (clutch to clutch wears out and without a TQ signal, the TCM cant compensate).

And no, they wont talk to each other. The LS1 PCM is VPW, the T43 is CAN. 2 very different protocols and neither controller has forward/backwards compatibility. The E67 is one of the few controllers that can do both VPW and CAN.

Erik, why is it you always have all the answers to all my questions !! You may or may NOT remember me posting a while ago about how to run a BMW I-6 on a GM ECU, once again you had the answers.. Well fast forward a bit, that car is basically finished but I elected NOT to convert the BMW engine over to GM ECU, it was going to turn into more of a project than I wanted on that old of a car..

Ok, so fast forward to last December, I did acquire a 2003 RCSB Silverado that's 4x4. Currently I am researching suspension options and have pretty much decided what I want to do.. I went so far as to acquire a 6l80e and an AWD Tcase from an '09 Escalade for a song. I want to put it in the Silverado and you've answered almost all of my questions, I do have one more that comes to mind, will the stock cluster continue to talk to the new ECU or does that require an upgrade as well ?

Thanks man, guys like you are the reason that forums like this one are such an awesome wealth of helpful information!

Hi Todd,
I try as best I can! Now that I look at your sig, I remember our discussions. Your profile pic threw me off!

In regards to the cluster, I *believe* it uses the Class 2/VPW bus signal to determine everything. It might work or it might not, just like the HVAC stuff. This might snowball into a larger project too, if the cluster doesnt work then you'll need to use a NBS cluster that communicates via CAN. Not sure on the HVAC stuff, it should work but I dont know offhand.