Hey folks, about a month ago the left rear drive shaft on my 97' sportsman 500 4x4 came out, it looked like the bolt that goes through the top yoke into the transmission backed out. I took it apart, screwed the bolt back in, everything meshed fine and the bolt was nice and tight and I resembled. Two days ago the bolt backed out again and the drive shaft came loose. What is causing this bolt to back out? should I use blue locktite to keep the bolt from jarring loose or do I have a problem with one of the u-joints? I appreciate the help, anthony.