Being that the Kaiser vehicle manufacturing operations in the South Bend area were a continuation of the Studebaker operations, and AM General was a continuation of the Kaiser vehicle operations, I don't feel it is fair to include the Kaiser years with the AM General years tally. So I currently give longest production to Studebaker.

As for Oliver, I'm not sure, but I believe they only built tractors in South Bend for about 30 years. Oliver tractors were manufactured for about 45 years, but most were built in Iowa in the former Hart-Parr factory and production of Olivers (along with Minneapolis-Moline and Cockshutt) eventually became White Farm Equipment.
Upon further investigation, Comatus may be correct as Wheel Horse began self-propelled lawn tractors in 1947. Interesting to note is that American Motors bought Wheel Horse, in 1974. Wheel Horse traded ownership again in 1986 when purchased by Toro. I dont know when Wheel Horse production ended in South Bend but I assume they surpassed Studebaker automobile years of production.
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