get the "shop manual" for the tractor well worth it! full diagrams of everything, along with detailed instructions in how to tear things apart, test and check tolerances, and how to put it all back together, and how much to toque things back down, it is like 150 bucks. but money well spent. it is i want to say 4 inches thick. the operators manual not really worth it for me, and only a few pages thick. but shop manual is well worth the money.
the manual i have covers 555A, 555B, 555C, 555D the different types of transmissions for each, the different engines for each, and if they have 4WD or 2WD.
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you can goto newholland aka ford website. and get into there online parts catalog for free. that just show diagrams. i use short cut link, on dealer i bought my 555c through. (faster than clicking through newholland website)