Stop in for a cup of coffee

Mattax said
I was using Rotella T 5W-40 for the Grand Wagoneer. Then changed to T6 because the formulation changed even though its "Rotella'.
Somewhere around 2017-18 the formulations were changed again.

Here's a VAO for Rotella T6 in late 2014.
It was still API CJ-4 (diesel) SM (gasoline) and no GF at all.
http://www.pqiamerica.com/June 2014/shellrotellat6.htm

Everything is more difficult these days.