How tough of a job is it to replace the clutch on one of these? I have done a lot of transmission work on other vehicles but nothing this large. Is there a special tool to align the clutch to the pilot bearing like smaller vehicles? Where is a good place to buy these clutch components?

 

I'm lucky I have a large truck parts store 15 miles away. They only sell large truck parts.
of course you can always go the dealerships for parts as well.
As a habit I always check eBay as long as i am sure what i am looking for.