I had the drainback problem bugging me because I don't drive my truck to often. The dealer did the tsb and now the tranny has a drip. Anyone know what they could have screwed up? It looked pretty simple .

They could have installed the front seal incorrectly. They need to be installed with the correct seal driver or they will leak.

My tranny leaked too when I first brought it home but I think it was because of excess oil on skid plates etc. Seems to have stopped now. Maybe your problem too. Give it a few days.
Richard