I have 229,000 miles on mine. At 185,000 I had to have the timing equipment replaced. At 215,000 miles I had an exhaust manifold warp. Not cheap repairs but nothing that busted the bank either. I only tow about 3500 pounds but have never had the engine heating up and I have towed over many 11,000 ft passes (most of the major ones) including I70, Trial Ridge Road, Beartooth, and 14A going both directions. We have put 50,000 miles of towing on the truck. I d3etermine my tranny gear by watching the tranny temp and shift if it gets above 200 degrees. I have never run out of power.