I had something like that happen to me. I loaned out a brush hog and the guy bent the drive shaft. I told him not to try to cut down 5 foot tall brush in one swipe. I told him to set it high the first time and go in low gear about 2 miles per hour. Instead, he set it low and went about twice as fast as he should have. The drive shaft bent under the stress. He told me about it and took the drive shaft to get it fixed. If your friend that you loaned the brushhog is a decent person, he should bear the responsibility of getting it fixed. Period!