To make the story short, 2007 model 850 hours. Original PTO has always done a safety stop when it's got to warm. About 200 hours ago, muffler and muffler shield stripped out and were removed. Recently when using PTO failed and never came back even after being cooled all the way down. I figured it was a no brainer at 850 hours that it was burned up and time to be replaced. I just installed a brand new PTO, muffler and heat shield. Mower fires up tranny drive works just fine but when you toggle to engage the blades there is no one home. Any body who truly knows their stuff please respond...