I should be able to help out, being an ex JD tech(big stuff though, combines and such). John Deere has changed mower models so much I cannot remember if the engine is a vertical shaft or horozontil shaft?
If it's a horozontil shaft, the clutch will be on the front of the engine, and may simply be unbolted fron the shaft and engine block after removing the deck belt and wire.
If it's underneath the mower, will likely be belt guides and stuff to remove too. Most of the electromagnetic clutchs just have a bolt holding the pully and cltch part to the shaft. Then can remove the magnetic coil and plate bolts, removing the entire clutch.
Might be able to go to John Deere's website, and and see an exploded veiw of the mower's clutch assembly on the online parts ordering site.
May have to jam a screwdriver in the flywheel ringgear/starter teeth or somesuch to break the bolt loose. I don't think the bolt is a left hand thread, but could be!
Really, I was a combine/4 wheel drive tech, not a lawn and garden man. Although we all worked on mowers on occasion (like the small engine man quitting
)