American Tractor was started by a DP from Europe after WWII. Terratrac was the brand name of the tractors that the company made.
American Tractor company merged with JI Case and the DP became the President of JI Case. The DP was a dishonest manipulator, as was his wife who was a stockbroker.
When Case introduced their new line of tractors, the DP had the dealer meeting in a bull fighting arena in Mexico, with bottles of Tequila everywhere in the arena bleachers. Case personnel circulated among the intoxicated dealers with order pads.
As the orders were turned in, Case stock soared - and the DP's wife was selling their personal blocks of stock at inflated prices. When the dealers sobered up a couple days later, they cancelled orders right and left - and Case stock fell and eventually forced Case into filing bankruptcy. But before the company filed bankrupcty, the DP & his wife had fled the country for some island where they couldn't be touched.
I wouldn't buy anything Terratrac just on general principle, plus I don't know if Case has any parts for them.