First, welcome to our community. We are glad to have you here. I hope we can get you pointed in the right direction with your issue.

That said, we are in the Introductions section and if you could I would greatly appreciate it if you could post your question in either the 3800 Naturally Aspirated section or in the 4T65E section. It sounds, based on what you are describing, like a drive train issue and if it is, if you post in the 4T65E section we have what I would personally consider one of the nations best 4T65E tech there that goes by the screen name of Trannyman95. If its not drive train related he can let you know and then you can ask in the 3800 section.

Not trying to be a kill joy, just trying to keep all the information in the right places.