I had a mower deck belt come undone on my X354 at 12-15 hours. My dealer jumped on it and got it done in three days. Now today at 20 hours it happened again. The belt is in pieces. I did not hit anything or do anything I can tell. Why would this happen again and why is the belt in pieces? I sure hope they can fix it as fast as last time because the grass is getting deep again. I cut at 3.75 inches so there is not much room for days going by with out cutting. I am haunted by the ghost of my LT155. I never had this problem on that tractor in 20 years. Any idea what would do this. I have the mulch attachment dealer installed. Help!!