It is pretty easy to replace the drive belt. I removed the blade drive belt and the transaxle drive belt slipped right on. you can download a routing diagram from the Hustler website. It turns out my problem is that a stick or something flew up into the belt area and bent one of the plastic cooling fins that spin with the belt. That bent fin was interfering with the belt and knocking the belt off. You might have a similar problem. I took the machine to the dealer to replace the plastic fins, but if this happens again I think I could figure out how to drop that drive pump and replace the fins myself.