After I posted on the thread. I noticed you said full manual valve body and depending on whose it is some of them do have a delay in reverse and never have any issues. Not saying that it is in the valve body. But of course, if you wanted to find out for sure, you could replace it with a factory valve body. Of course, that's easy for me to say. I have valve bodies everywhere we do it for a living. It's your call, If it has good positive shifts at wide-open throttle, you're probably okay. If it is a TCI , I would not trust it drive it around, but stay local. We have used their products for many years, good stuff but for whatever reason on their 4L80E valve bodys they have some more research to do.