Alright, we are back in business. I just towed 20k up to Oregon and back so total round trip of just over 1K miles. The build was phenomenal. No leaks, no issues, doesn't look to be burning oil. (oil change up next to double check the internals). Power was smooth and on point. I was able to pull the 7% grades at 50-60% throttle at 60-65mph. EGTS ran a bit hotter than the stock motor (might be valley turbo, might be injectors, IDK?) by about 150-200deg. So when pulling relatively flat ground, it was easy to see EGTS start to bump up to 1300 with slight inclines where I was 1100-1150 on those before. The stock Duramax is rated 1375 constant duty (i think) so I'm not too concerned there. I also towed a 7% grade in 98* weather which is over 6 miles long. About the 4 mile mark, we hit stop and go traffic so we did get some heat going on at that point, mainly trans temps. Even with the Mike L cooler (setrab), trans temps started climbing while pulling the last 2 miles going 5-10mph. It's tough to use hydraulic pressure to move that much weight for that long with little to no airflow at 98*. Just as I crested the top, trans temps were at 260. As we used trans shifting going down the back side, they briefly came up then quickly fell back to normal temps after 4-5 miles of coasting. That being a rarity, the next few passes we pulled at speed - trans temps stayed normal and TC was locked. ECT (with XDP xtra cool RAD and Xtra cool fluid) stayed around 180 (mishimoto lower temp stats) but on the long passes at 98* i did see temps come up to about 220-230 on a few short stints but never above.
I have a little work to do on tuning. But from a build perspective, I think we've made it. Thanks to everyone here who had input!
One last build question - the hot side intercooler pipe does like to "slip" a bit under the higher temps. What do you guys do to keep that baby locked down? If I clamp any more, I think I'll crack the rubber but it still slides off the turbo a bit so the pipe rubs against the hydroboost cylinder.
does anyone know what it’s from? It almost looks like a dowel pin. 
