Mercon or Dex/Merc vs Mercon V

[Byrnedw]

Hi, my first post here. I recently changed the fluid in my 4R100 trans and after research and advice used Mercon V instead of Mercon which I had used in previous changes. It was my understanding that the Mercon V replaced Mercon sometime around 2007. Trans shifts and operates perfectly however it does vent oil out of the bellhousing when warmed up. Would this be coincidence or is there some kind of incompatabilty with these fluids in a Ford Reman trans with 65000 miles on it. I'm wondering if the font seal has some incompatability or fluid properties are different and heating trans up. Has anyone else experienced any issues like this? At this point I do not have many miles on this change. Thank You