OP here, still traveling. We’ve added another 1k mikes towing heavy, and probably another 1k miles without the 5er since original post.
Just leaving Rockies behind us but still at 7000ft and have crossed the continental divide a dozen or two times since last posting. No more problems...yet...fingers crossed. Taking it in for oil change in Cheyenne tomorrow, still have 1500-2000miles left in this trip.
I have been a little gentle on it (not hammering down) but have let cruise control rev it up pretty hard on some of the pulls.
Not sure what to think about exhaust brake. Last mechanic said not to use it much as it might aggravate the issue I’m having. Prior to that it was the second button I pushed (after tow/haul) every time I took off pulling. Since his advice I’ve only turned it on when needing it on a downhill. Advice here seems to be “use it” so maybe I’ll tend more back to previous practice.
I’ll talk with mechanic tomorrow, but currently planning on at least finishing trip and dealing with at home. If “babying” it means the code seldom fires, and I can avoid limp mode, not sure if I won’t just continue to live with it instead of shelling out $4-6k....don’t know... we’ll see...