I just bought it yesterday off facebook, and now reading about what I bought here, I see many things I should have checked 1st. The brush hog is located where I'm going to use it, which is not where I live. I knew the blades are stuck, and won't rotate, but it does spin freely. The owner said it was used about 3 hours in the last 15 years, and was covered in blackberries when they bought the farm 20 years ago.. It looks rough, but so does everything I own, including the tractor that will run it. The deck is dented, and patched. The gearbox seems to function smoothly by hand, but when I removed the oil level plug it was under pressure which surprised me. The oil smelled bad and seemed thin. I'll remove and sharpen the very dull blades, change the oil, check the clutch, but is pressure inside the gearbox on a cold day a concern? Is there a breather that keeps a certain amount of pressure in there intentionally? There seemed to be about 5psi, maybe a bit less in it. Thanks