Have a recently built 4l60e. Everything is good, used probably 98% of the info I learned in here.
Changing filter and adding going to synthetic fluid. Used Valvoline Dex 3 for initial fill. Trans has around 6 or 7k miles on it. Planned on using Valvoline Dex 6, but for one only can find it in stores by the quart. They have Max lif multi vehicle synthetic Valvoline in the jugs. I looked up the specs on both the Regular dex 6/Meec LV and the maxlife synthetic. Noticed some of the specs are different main one and, pretty much only one I know anything about is viscosity.
Question is what is better, or what determines what? Lol.
Using Royal Purple oil, there Max Atf isn't compatible with dex 6 so that's out. Have used Redline previously in a turbo DSM. Am I over thinking this? I put too much time, effort and thought into building this trans NOT to put time, effort and thought into the fluid that's in it and will go in it.
Redline has a few types that could be used. Amsoil looks like they have 1 or 2. Valvoline is an option and of course A/C Delco Dex 6
Thoughts. Opinions.

 

I bought the Dex6 at napa,, so I'd know where I could get more no matter where I was..

 

Are you running a stall converter? I asked Yank what fluid to use in my PAS3400 and they said any good quality non-synthetic. ???

 

Run Dex/ Merc or Dexron-6... It doesn't really matter.

However, I would NOT recommend ATF additives, and Fluids that are branded as "High-Mileage" or "Max-Life".