What can I do to fix the clutch slip on my John Deere 1070 tractor?

I have a John Deere 1070 with a slip in the clutch. The dealer says I need to replace the clutch, and gave me a high priced quote. I was hoping there might be something I could try to fix it myself, or how big of a job it would be to replace it myself. I am mechanically inclined and found out I can buy the parts for a quarter of what they want to do it for.What can I do to fix the clutch slip on my John Deere 1070 tractor?That gear box must come down and it it heavy heavy heavy!