Have a Gravely ZT1740 and I put it in the shop to have them check the deck belt and change the muclhing blades. The belt was slipping in high grass and wasn't mulching well anymore. When I got it back they just changed the blades and said the belt was good. When I asked why it is not mulching well he said it's the deck pulleys are worn out. So can you get the pulleys at a better price off the internet ?