My 240D is a 1981 tractor, and at least then, most of the engine & driveline system was fairly interchangable. I have on occasion, when I felt a need to bleed across the counter, bought parts from one of the local JD dealers. The JD dealer is fairly conversant with the old machines, given that the ones he sold with the funny paint job are still running and working.
The so called Yanmar dealer I bought from parted ways with Yanmar in 84, and became a Honda dealer. The treatment I got from him after dropping close to 10 grand in 1981 money across his counter definitely cost him a lot of business, because I let my feelings be known far and wide.
Very few red Yanmars wound up around Rochester, NY, but there are one he!! of a lot of Kubotas, primarily because of the Kubota dealer's attitude and support of his equipment.
There are also a lot of parts available for the old US yanmars available from NAPA, assuming you have a NAPA dealer who handles NAPA's agricultural lines. Prices ain't bad either.