I had the owners manual and service manual for mine and recommend you buy those. I also have parts manuals for my older tractor and find that with the advent of computers that many of these part numbers have been updated. J D parts online is good enough to suffice for this if your machine is listed, then skip the parts manual. I recommend you sign up for JD parts on their website, this is a free service. This allows you to look up the cost of the various parts and store them in shopping carts and order online or print to take to your dealer.
I was typing while Storm56 posted, sounds like the way to go.