Looks like a mineral Dexron III type. Ok, I can give it a try.
I tried the Agip product (fully synthetic). It shifts faster but it's easy to grind
Synchromesh shifts smooth but it's too viscour in winter and it takes way too long to shift as long theoil is cold.

I also think my tranny is not 100% ok, but I'm sure that what I described at the beginning of the topic makes th esituation even worst (RPM rising after closing the TB).
What kind of BOV / Bypass valve are you using?