Brad told you the problem , you bought a spreader that was set up for a bigger tractor, you have cat 0- for lawn and garden all the way up to cat 3, that's what we have on the articulating tractors, Cat 1 is for Ford small JD up to about 80 hp, you can put smaller stuff on bigger tractors, just buy a sleeve to slide over the pins, in the reverse situation a replacement is about the only thing to do. These are things you have to watch out for when buying equipment....