New TCI Streetfighter won‘t shift in 3rd when hot

So just to be sure I ordered the recommended TCI 950641 transmission oil.

It is much thicker than the Dexron 3.
Like warm honey and water.

First test drive went well so I think the oil solved the issue.. Shifts up and down in every gear.
I will do another test drive when it‘s warmer again just to be sure (at the moment 50°F).

The used Dexron 3 oil smelled like new so I don’t think there is any damage.