Cummins x15 knocking noise

Got the same problem. Did you resolve it?

 

We need to list whether these x15s are an "E" (economy) or the "P" (performance) series.
My 2021 567 has the E series at 500, and it sounds like it is about to leave the entire bottom end laying out on the highway. It makes noises that do not sound like an engine, but more like industrial manufacturing. Yet,...it is supposed to be normal.
It's been to the dealer, and it's been to Cummins. No problems.
A couple 589s with the P series at 605 come around and tell me the same thing about the E, that's normal.

So it depends if these sounds show up all of a sudden, or whether one just notices them after finding the volume button on the stereo and turning it down. A W9L came through the yard with an obvious E Cummins, then two 589s with Paccars, following them a very nice Cascadia with a Detroit. Not much has changed over the last 45 years (or more) with being able to ID an engine by it's sound. I'm so old I remember the Hall-Scott 1,000cu/in gas engine with the updraft carburetor. Sitting in the grain line at T4 and T5 in Portland, every morning the common cologne fragrance "starting fluid" would fill the air, and you knew you were very near to 318 or less often a 360 Detroit. Oh those were the dayz..........but I digress.