As a matter of fact, I have tried it in my AOD, and was told that it was bad for it as well, as I was having it rebuilt. So when it came time to do work on the bird, I just followed what I had been told by countless people on this board, to do the J-mod and be done with it. So far, no problems. I have not tried it in a 4R70W, and will not. I cannot afford to guess if it is actually bad for my trans. I know the J-Mod works, so that's what I went with. If someone else has installed the Trans-Go kit and had no issues, then more power to them. To each their own. I was offering an opinion, therefore it should not be taken as "the" word. Just a suggestion. It's his tranny, so it's really up to him what he does.
These are highly engineered precision vehicles, the first step in diagnosing the problem is to strike the suspected offending part sharply and repeatedly with a blunt object, then re-test.