a tail of two trans... lol got the old one next to the new one makong sure i have all the ezternals i need to go on. i had to take the shift conncting ball/lever of fthe 4l60 since the 4l80 has a small ball on it. from what i hear the exisisting shift bracket fits and works on the 4l80, but i have the old hardware off the 4l80 is i need to modify anything. i guess i dont need the electronic thing thats on the side of the 4l80, so i took that off.