changed oil replaced clutch

[wildbill]

I know this is a repeat question but at $300.00 mabey its worth refreshing. I changed my oil from dino oil over to Rotella Synthetic Diesel oil because I always have it on hand and I saw on here somewhere that this oil has no friction modifiers that will make the clutch slip. After much research best I could tell this type of oil was a good choice. A week after changing over the clutch started slipping. I just paid my mechanic $300.00 to replace my complete clutch assembly. He said my springs were weak and the teeth on some part I dont know the name of was wore down but the friction pads of the clutch were not wore out. My 03 Nomad has 30,000 miles on it. Has anyone had the same trouble or was it just time for a clutch. Seems like Synthetic oil has now become the thing to do. Yea I know I could have bought synthetic oil at the motorcycle stealership, it just seems they think its worth a little to much money.