Margaret, you nailed it, that gritty mud just grinds cheap oil to dust in no time. @the_leo you're right, a $400 lesson stings way worse than it should, especially when you're kicking yourself for trying to save a few bucks. I've seen guys lose whole shifts on the cutterhead over this exact thing, and it's never worth the headache just to pinch a penny. The heat and sediment in a river like the Savannah turn cheap lubes into sludge way faster than you'd expect. That mechanic was probably shaking his head the whole time he was fixing it, same as mine did.