2019 5.3 8spd transmission issue

[J_Cool87]

Hey guys, so I turned in my truck today for scheduled maintenance as well as my truck has been having an issue it seems with the transmission falling on its face in between gear changes. I have done some research and this was a common issue with the 204s and up i believe. Havent heard much about the 2019s and up. It so far has happened everyday this week on the first startup of the day leaving my house. It has only done it once or twice after driving it for a bit. Well I get a call from the dealership and firstly they couldnt get the problem to reoccur, which i figured was going to happen. It only sat for a little while. Also they said they had retrieved some lean codes because of my aftermarket intake and muffler delete and are trying to say that that is possibly causing the issue. The dealership is saying because of my modifications they will not warranty for repairs and i believe for a fact my mods are not causing the issue. How should I proceed? 

[Jac365]

Are you talking about a hesitation between one of the shifts after the truck has sat all night?. If so there are threads here that mention the torque converter draining during the night and that hesitation is caused by the trans fluid filling the converter again.

 

On the other issue with the dealership. W.T.F....

[Brianibew]

Put the OEM exhaust back on and bring it in.