OK, I've read 500+ posts about the Lucas Oil Stabilizer in diesels and how it is not recommended for PSDs. I can't however, find anything about Lucas 15/40 Diesel Oil. It is CP-I rated, advertised as High TBN. Lucas says it has a "detergent package" that is beneficial to diesels. Says it keeps more contams in suspension than comparable oils (sales pitch). I do 5k changes with good Wix filter. I definitely notice that the oil is a little thicker than Rotella, Motorcraft, Royal Purple (in the jug). Coming out of the drain plug, it appears cleaner than any other oil I have drained from any other engine. I chose it b/c of it being thicker. My 99 7.3PSD had 200,000 on it when I bought it in 06. Thought a little thicker would benefit the slack on the engine insides. What are you guys thoughts? I do notice that the engine runs smoother/quieter than with Rotella/MC.