Well, I know a much cheaper way to protect the tractors, and that is. I was thinking about it and came to this conclusion. I have a 4 cyl Camry, and if I drive it at about 55 miles per hour, it will be running at about 2200 RPMs. Which is probably close to the rpms most run their tractors at. So we will change that to 50 miles per to make it easier. In 10 hours it will be in the area of 500 miles, so in 100 hours about 5,000 miles. What I'm getting at, is most say change the regular oil at 100 hours, so that is like driveing you car 5,000 miles on a oil change. So if you are using your tractor enough to worry about wearing it out, then change your oil at 50 hours, which would be like changeing at 2,500 to 3,000 miles like a lot of people do with their cars. I personally change my regular oil in my cars and trucks at 5,000. Never had a motor problem, or needed any motor work so I'm happy with that. Of course I generally trade them in before they have 200k on them so don't know if the next person has a problem or not. By the time they are that old everything is getting old on them and I want new. I guess if I were to drive 50k miles a year per car, then I would keep them longer. But I don't and have 2 cars and a pickup, so they get old.