humanpotatohybrid wrote:
Previous owner used type FA in mine and it seems to work well overall.https://www.napaonline.com/en/p/NOL75205[/quote]

I hadn't heard of Type AF, so had a little look online. Some say AF and F are the same, that type AF is just an updated version of type F. Some say AF is better than Type F for older transmissions, that it has different friction modifiers.

Does anyone know for sure if they are different and if one or the other is better for an Ultramatic?

*I have Pennzoil Type F in my Ultramatic and it seems to be okay.