Short of starting another oil thread, I recently gained confidence in the use of 05-40 Moble One, also, Rotella T synthetic 05-40, both diesel rated.

You need to stop thinking 5 weight (thin as alcohol) is what is running in there (not providing enough film thickness) and consider that it is 40 weight instead. The 5 is only representative of it's ability to lubricate properly in very very cold climate conditions at start-up. After the engine comes up to temperature, the oil lubricates to 40 weight viscosity, but no thicker.