Update.
The rig is now at the cummins dealer for troubleshoot/repair. The final 21 miles were behind a tow truck after the second Engine Stop incident.
Preliminary diagnosis. Many Severe Temperature episodes recorded in the ECM. Not supported by observed operating parameters. Coolant level remains stable, engine heat dial running at normal, and transmission temperature level at comfortable.
Now, the right side slide will not open = no engine access through the bedroom. Mobile RV tech will be onsite tomorrow, anticipate easy fix? (Left side works Fine)
Stay Tuned & Tnx for the great experience based advice.