First, see if it has a FERGUSON tag or a DEARBORN tag on it. To me, the tag makes it more valuable, and many do not have tags, and s Royse said, are missing the crucial front bracket and chain assembly. You need that piece in order to raise the entire tractor up, but, it is not required if only the rear needs to be lifted. There were at least four different versions of the jack. Here is a bit of the history on the jack:
When Ford released the new 9N tractor in June, 1939, it rapidly became very popular and sales began to pick up as the new 3-point hitch was and did revolutionize farming from then on. It was, as Ford had envisioned, becoming the ?world tractor? as what the Model T did to cars for the world auto industry. Many individuals were determined to get in on the action and thus began producing items to supplement the new tractor. The tractor jack was one of those items. Three fellows in Olathe, Kansas, Tom Poor and the brothers John and Herman Kisinger designed and had built a device that would raise the entire tractor up in order to make a fast job out of changing the tire tread width. They filed for a United States patent on August 22, 1940, a little over one year since the 9N was first released into production. The Ford and Ferguson ?handshake agreement? of which the details were never written down, only known to the two men, and would never hold up in courts today, did publicly stipulate that Ford would manufacture the tractor and Ferguson would handle distribution as well as procuring and supplying all the implements. The only implement that Ford-Ferguson ever built was the plow. All other implements were designed or revamped by Ford engineers, but built and supplied to the Ferguson-Sherman Manufacturing Corporation under contract, which allowed Ferguson-Sherman to attach their ID tag. The original K-P Tractor Jack for the 9N attached to the lower lift links and will not work on the later 8N and up models. Finding and owning one of these would be unique. Soon, a design change made it so it would mount under the rear axle. Ford-Ferguson, and later Ferguson himself tried to buy out the patent rights from K-P MFG, but they would not sell. In 1946 when Henry Ford II was in now in charge, he dissolved the handshake agreement, which sent Ferguson to England to make his own tractor, the TE20. Since US patents were not valid in the UK, Ferguson was able to produce his own jack, pretty much based on the K-P model. Ferguson had taken out numerous patents on the 9N tractor as it was in his name, since Henry Ford didn?t believe in them, ever since his victory over the Selmer suit, and had no use for lawyers. A lot of the patents Ferguson ?owned? were not his designs. The 3-point system was actually designed by his chief engineer Archie Greer. Thus Ferguson supplied a tractor jack for his line of tractors, the TE20, TO20, and TO30. There were some design changes, but not much. A special flat steel plate was offered as an option with all the jacks to support the front bracket, but I have never seen one, probably because no one knew what it was - there was no part number or ID mark on it so it looked like just a plain flat piece of steel.
Here are some pictures of my Dearborn Tractor Jack in actual use. I use it exclusively whenever I switch from my work wheels/tires to my original ones for shows. It is the most effective, fastest method of changing out the wheels. There are DIY plans on the other Ford-N-Series Tractor club web site for FREE download for anyone who is innovative enough and has the right equipment to make their own. You?ll need a tube bender and welder for sure.
1948 FORD 8N & DEARBORN TRACTOR JACK: