It was the main clutch housing on the main shaft. Actually I don't know the cost as the parts we robbed to fix it came off of a used R62 on the dealer lot. They sent our old one away to get machined. I was surprised at how easy that was to take apart and put back together. It looked like it could be a son of a ____. Dealer didn't really have an explaination for why that happened, allthough this machine has done a pile of road work, which may have had something to do with it.