My family and I were going up a canyon called parleys way. It's like 5 miles long is 4-6% grading the entire time. My dad had forgot to pull the truck out of od and into d so engine worked harder than it needed to. Also had a camping trailer with either a 75 or 100 gallon water tank which means 625-800 extra lbs. Also had a 4 wheeler in the bed that is about 800lbs. We had to stop because the engine was starting to act and sound funny. When we opened the hood none of us could belive it the headers were glowing bright orange for the block back and we could feel the heat about 3ft from the truck. Just wnated to share this story.