Never thought of this as a possible problem until this thread. Several years ago we had a customer complain that a rental machine they got wouldn't climb like the previous machines they rented. This one was 50% heavier than the previous ones with only 10% more power. Job was compacting clay liner on landfills before filling, 50% slope. I flew out, instrumented the machine, and had no problem climbing the slope by watching the tach and feathering back on the hydro keeping the engine at full power. It was slow climbing, but I could do it. Then had them get their operator to show me how he did it. He started up the slope and as the engine pulled down, he would give it more propel lugging the engine down until it died. He kept doing this because on a car or truck when you need more power you press harder on the accelerator. I showed the operator the correct procedure but it was tough because he had this "need more power, give it more throttle" process ingrained. Couple weeks later I get an email from the dealer, engine now running bad, discovered broken crank. Sent a person from engine division to check it out, could not find a flaw in the crank so had it sent to metallurgy. They also could not find anything wrong but the crank was broke, and this just doesn't happen so give them a new engine. This just seems so odd. Lugging an engine is bad but I would have predicted bent or broken rods before broken cranks.
