I have a 2 year old zero turn Hustler Raptor. It is my second Hustler in 13 years .It sounds like a popping noise under the deck continuously when the blade is engaged or not. Is there any chance that there could be a fracture in the medal. My mechanic just put new blades and a couple of other things and cannot find the problem. The noise seems to be under my feet and I'm afraid its going to fall apart. I'm on a fixed income and cannot afford for my mower to break apart .especially since I just finished paying it off .I'm praying that someone can help