Have a 2006 Husqvarna 36 W/B. Model is a WH1536E Hydro Drive. I got 40 hours out of the original belt with a mulch kit installed. I then swithced to gator blades 1/4 thick (.250) new belt lasted about 5 hours. Then I tried an arimid belt same results. Next I removed the gator blades and put a .203 thick set on it. This one got about 6 hrs on it and came apart. So I am on belt # 4 and am kinda P.O.' d cause the belts are 39 bucks each. I would really love to hear any insite into this problem. I have checked all the pully's and the tensioner no binding or dragging. I Also need to mention that the belts are not breaking they are stretching to the point of running off the pulley. I have also maintained this unit since day one per the book.