Yep! Rotella 15w40. When bought a new 2000 F-250 with the 7.3 diesel. First oil change I went and got a 55 gallon drum of it from Sam's club.
Use it in everything except the air compressor and the newer cars that require synthetic.
I believe I am on the third drum in almost 21 years.

The old 7.3 is still pulling good!, But rust, is another topic.
Don

1967 GMC 9500 Fire Ladder Truck
"The Flag Pole"
In the Stovebolt Gallery
1946 2-Ton grain truck
1946 3/4-ton pickup,
1953 1-ton pickup
1957 1-ton flatbed dually,
1954 Pontiac Straight Eight
Of all the things I've lost in my life, I miss my mind the most!