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Hello from Kentucky, I Need help with a transmission question.

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I am glad that I found this site.

I am a Chevy guy with a dozen trucks from 1947-2008.

My main focus is 1955-59 Chevy Apache trucks, I have several.

My question is about my 2008 Chevy 2500hd two wheel drive truck. The 6L90 was bad and I put a 2016 6L90 from a 3500 express extended can in it.

It will not shift out of 3rd gear.

Can I just have a GM dealer reprogram the transmission, or do I need a 6L90 out of a different truck.

I have another 6L90 sitting on the bench, but I do not know what it came out of.

Any help would be greatly appreciated.


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  • 1 month later...

@TruckGuy40165 Did you ever get a firm answer on this?


I'm looking for similar info myself; wondering if an earlier 6L90 will work if the correct year valve body and TEHCM is used. I have a 2016 needing a rebuild and found a GM reman from a 2009.

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