It doesn't have to be a diesel either, it's a good base oil
plenty of molybdenum in it, especially if it's a blend like 5/30 10/40 15/40, even 70wt

,
most with detergents added
it's not a straight weight SEA
like the org. like '
the org. Rotella' from Shell Oil, (IIRC for Ford org.)
great oil in it's own rights
my Granddad Elmer/Whitty (RIP) was an Engineer VP for Shell oil,
from the 1930's to 70's, VP in lubricants for 44+ year
Many, many a big rig diesel long haulers,
has gone 1,000,000+ to 2,000,000+ miles using it
much like the org. Delo Oils for GM, from Chevron/Standard Oil
my uncle Ron (RIP) was a Engineer VP for Standard Oil for 45+ years
albeit I'd still prefer to use Rotella 1st, in any heavy duty engine