Nice work on the write up(s)! A year ago I purchased a used 2006 24D on the GM chassis and LOVE the torque and pulling power of the 6.0L. If you ever experience your engine temp running hotter than normal, and you don't hear the clutch fan kick in. Replace the fan clutch with a Hayden severe duty unit and never see your temp gauge go above 210 degrees again. I had tried a new GM fan clutch and mine would still run hot on long hard grades and still would never engage. The Hayden unit rarely fully engages, but solved my running hot under load issue once and for all. Also inspect your exhaust manifold bolts. One of mine has broken off (pass side rear bolt), but has yet to cause a leak. I will replace all of the failure prone exhaust bolts if and when a leak starts. That's it for now, from one fellow rider to another "pinn it" LOL