Newmember2020

That is what I thought but didn't want to wast the $110 pus tax.

That's what I thought. The dealer told me that flashing it would not remove the tune. I never told them about the transmission problems.

I recently bought a 04 Sierra 2500HD with a 6.0. The guy that sold the truck said that his grandpa use to use it for towing and had someone put a tow tune on it. Currently the truck does not go into 4th which the previous owner said is because of the tune. I know that overdrive going out is a problem with 4l80es though. Could his story be true? If so is there a way to remove the tune? I called a GM dealer to see if they can flash it, but they said it wouldn't help. If it's possible that it is tuned could i just get it returned, possibly with a handheld or Black Bear Performance? I knew about the problem when i bought the truck and I got the truck cheap enough that even if it is the transmission and needs a new one I'm well under resale value. Any advice would be great.