what year 4l80e
My personal opinion is to avoid the TransGo kit if doing a rebuild. It's a decent kit if you are using it as a temporary setup to use a wrecking yard trans.
The multi-layer separator plate can cause issues and if you use the TransGo kit, don't use the pressure relief portion.
I designed a valve body kit for the big power applications, and in lower powered applications (750 HP less) any knowledgeable builder should be able to setup a 4L80E to work well without a valve body kit.
The pressure relief can cause all kinds of problems. Not very high quality parts, in my opinion. (That's the nice version of what I think of them...)
The '80E is pretty easy to setup to take some decent power with just careful setup, pressure and orifice sizing.


