We had a neighbor who had a JD 520. He was "laying by" his corn with a 2 row 3 point mounted cultivator. Corn was close to waist high so he was running about as fast as he could and stay on the row, probably at least 4th, or maybe 5th gear. His clutch release wasn't adjusted properly. He later said that he knew he should have fixed it first. Almost cost him his life. There was a big, wide ditch at one end of the field. Probably 20 feet wide and 8 feet or more deep. As he was coming to the end of the field he started jerking the clutch lever to stop the tractor and it wouldn't release. He later said he was standing up jerking on the clutch lever as hard as he could as the tractor went over the edge into the ditch. The tractor landed completely upside down in the ditch. Fortunately, there was very little water in the ditch but he said when he came to he was laying on his back alongside the engine with the clutch housing about 3 inches above his face. Shortly after that he traded the 520 for a 2010. Not sure he got a better tractor but at least he didn't have the hand clutch to deal with anymore.