Look at the picture I posted. Is part #16 what you are looking for..?? There are a few used ones available out there. They look to run about $35.00 plus shipping.
You can enter the part number in a search engine ( I use Google a lot), and find several.
If this is the part you are looking for, the part number is NCA475E. If you ever want to do a part # search, find the part number like I posted. Put your cursor (pointer on the screen) at one end of the number. (Left to right, or right to left, it doesn't matter) Hold the left button down on your mouse. Scroll across the number, it should turn blue. Let off the left buton on the mouse.
Then put your cursor (pointer) on the object in blue. Click the right button. A small menu should appear. Click the left button, and select "copy".
Go to a search engine, and in the search window, put your cursor in the space where you type what you are loking for. Right click, and a menu should appear. Select "paste", and your part number should appear in that space. Hit the search, and hopefully you will find pages/ sites, associated with that part # Just be sure not to include any periods, like above...
Or... You can just type in the part # in the search engine. Copying and pasting are a lot faster, once you get the hang of it.
I did a search on tractorhouse, and there is a fellow on there that has 2 in stock. The link is below. They have a parts search in the left menu. Bring up that page, and type in your part #. I didn't look to see if he had a price. You may have to call for a price.
Used Tractors at TractorHouse.com: John Deere Tractors, used farm tractors and farm equipment, Case IH, New Holland, Agco, Caterpillar.