Would this be a easy swap? '08 2WD 6L90 to replace '07 4WD 6L9

Big Tom · February 9, 2016

I've looked around and can't really find the answer to my question so thought I'd try on here.

I am building a project '49 Chev truck and the donor vehicle is a 2007 3500HD 4x4 with a 6L LY6 motor and a 6L90 transmission

The '49 I want to be 2WD and not 4x4, so my plan was to sell the transmissions/transfer case and purchase a 2WD 6L90. I found someone selling a very low mile 6L90 from a '08 2500HD, so I was planning to buy it but my question is about the '07 ECM/TCM, would I need to do any reprogramming of any sort to get this combination to work? Or does the computer not really care if it's a 2WD or 4WD transmission it handles it the same?

I know I need to get my ECM reprogrammed to eliminate the vehicle antitheft and some of the other systems I'm not going to be needing, but I wasn't sure if I'd have more needing to be done if I switch transmissions as well.

Any advice is appreciated

Big Tom · February 9, 2016

Not sure if it matters, the guy selling the 2WD transmission says it was behind a LS3 6.2L

Chris · February 10, 2016

Tail housing and output shaft will have to be replaced. Not cheap or easy.

Big Tom · February 10, 2016

Don't think you got what I was trying to accomplish.

This drivetrain won't be going into the same truck, not at all completely different frame/rear end everything I'm pulling the whole drivetrain out of the donor and scrapping the body. I just need a 2WD transmission, because the truck has a 4WD version would I require any special tuning to get a the 2WD version to run properly with it? Or would the ECM and TCM work just fine with either combo?

The whole point of me wanting a 2WD versions was to get the different tail housing and output shaft

Big Tom · February 10, 2016

Thing is I don't understand the relationship the ECM and TCM have, no one can really explain it to me thus far. If I take my LY6 6.0L motor out of my '07... mate it up with the '08 2WD 6L90... is there anything special I need to do to the TCM to let it know that it's hooked up to a 6L motor opposed to the 6.2L motor it had before... or vis versa do I need to do any special programming to my ECM to let it know it's now got a 2WD 6L90 opposed to the 4WD 6L90 it originally had from factory.

Or maybe the ECM/TCM don't talk at all like that and this is a moot point just bolt it on, get a tune for the engine and off I go? I don't know.