It's pretty impossible here to find the same luricants as in North America.
We have other brands and it's a try and error game to find out what really works.

I first tried two Dexron III rated oils: BP Autran DX III and Agip ATF.
Both are fine in automatic transmissions but the BP oil works much better than Agip in the T56.
BP is mineral, Agip is semi synthetic and a little more fluid than the BP oil.
BP is not bad; Agip is something I don't recommand: it feels much more notchy and it's easy to grind, especially going to 2nd and 3rd.

I then tried GM Synchromesh (part no. 12345349).
You can find it at every GM agency.
It shift smoother than the BP oil and I'm happy with it.
Don't expect to shift faster because those trannies aren't made for that.
But smoother.


Greetings from Switzerland - Stefano