Thanks MTWallet. I misspoke about the pulley's; I didn't count the tensioner pulley. Sorry for the confusion. Well, I bought a new belt from the Hustler dealer ($27.00!, does anyone know if I could get the same belt thru an auto parts dealer by cross-referencing the belt #?, $27.00 seemed pretty steep to me) Anyway, I installed the new belt and turned the motor over to see if I could tell where the trouble is. turns out the pulleys over both rear wheels have plastic fan blades attached directly under the pulley. If everything is aligned perfectly, there is a little less than an inch clearance between the fan blade and the belt. Two of the plastic flan blades on the left wheel pulley are bent upward just barely enough to strike the belt when rotating. I'm afraid that fan blade assembly will need replacing. I'm guessing when the belt slipped off originally it caught the blades and bent them up. It looks to be a little more than I dare to attempt to replace myself, so I'll take it to the dealer. The machine was purchased new from them earlier this year, so it's still under warranty. Do you think this issue should be covered by the warranty?