I rebuilt my 6R80 trans with Exedy clutches and a billet shaft in preparation for using a transbrake. The car already had a 3200 stall converter before the build and it acted as it should. After the build, not only did the converter get much tighter than before, it was tighter than it was when it was stock. I had it checked out by a trans shop that was familiar with the 6R80 and with modding it for performance and durability. They found no issues with my work and so I did more research and found another 6R80 that was doing the exact thing mine was and the issue turned out to be the lead frame.
So, I replaced the lead frame and it does seem a little looser, but not like it was before the build.
I received a reply to one of my threads on the issue and they mentioned that they were told, by a fairly reputable tuner, that the tune needed to be modified after a build. I'm aware of the need to make a few changes for the stall converter, which I already did, but are there other areas that should be addressed after a performance build?