Hey, been rebuilding a 4l80e and watching your performance build series while doing it and wanted to say thanks for the direction, has helped me out tremendously!

I needed to do a case swap on one of those back in the 80s. The rear of the case was worn where the sealing rings on the output shaft cut grooves in the case, so I did a case swap. I learned later that a tool and driver was available to repair this area much like when the governor on a 350 or 700R4 wore out the bore in the case. After boring out the case, you would drive in a sleeve to repair the bore. I didn't do enough of the AODs to warrant buying the tool. I'm guessing that if they made a tool for this that it must have been a problem for that particular transmission.