What is a 4L89E? You mean a 4L80E? http://www.v8buick.com/index.php?threads/got-jiggy-with-it-4l80e-behind-455-bbb.302742/
Larry, Neither the op of that thread or my brother Chad rebuilt theirs. Was reaching out to the dark side to see if anyone else got into the internals.
It's a 400 with overdrive and electronic control. ever think of simply Googling it? https://www.google.com/search?sourc.......0....1..gws-wiz.......0j0i131.hXbp3hj9GFo