tranny problems.
 

My truck is stuck in 3rd gear... no one to work on it. I have a tune on it and I am not throwing any codes. i have flashed back to stock and still nothing. It is literally locked in third. Could this be from towing 5000 lbs up hills? If the truck is rated for 8000 i know the warranty will cover it but not a dealership anywhere. Any suggestions.

How do you know its stuck in 3rd....2nd is the defualt gear...you climb under and check all the connectors?

I know 2nd is default but it is not stuck in second.........its in third. I took it to a shop today and they even said it was stuck in third but with me leaving they did not have time to get into it and tell me the problem.

Disconnect the battery for 15 minutes and re-connect it. See if that fixes it.