Tractor Trendsetters: Ford Select-O-Speed Transmission
Written by Larry Gay
Fifty-one years ago in February 1959, the Tractor and Implement Division of the Ford Motor Company introduced the Select-O-Speed transmission for the Ford 601, 701, 801 and 901 series of tractors. It was a full powershift transmission which enabled the operator to shift on-the-go between ten forward and two reverse speeds by moving a single selector lever located under the dash. There was no traditional clutch or clutch pedal, although an “inching pedal” was provided to assist in hitching the tractor to implements.
The concept of the full powershift transmission originated with Howard Simpson. Simpson was a Ford tractor engineer during the 1920s and developed the fenders which prevented the Fordson tractor from tipping over backwards. During the 1930s, he developed a series of experimental tractors for Henry Ford and was slated to be the lead engineer for the Ford-Ferguson tractor before he resigned. He then developed many transmissions designs for cars and trucks and during the 1950s all three major auto companies paid royalties to Simpson for the concepts they were using in their automatic transmissions.
Ford’s advertising emphasized the Select-O-Speed transmission was not an automatic or fluid drive transmission, but was a mechanical transmission with planetary gearsets that were shifted hydraulically. There were four planetary gearsets in series, with the first three being controlled by three brake bands and three clutch packs. The fourth planetary gearset provided a constant speed reduction. Moving the selector lever operated six hydraulic valves which in turn controlled the brake bands and clutch packs.
One Ford executive became very enthused about the concept and convinced the company to put the Select-O-Speed transmission into production without the approval of the Ford tractor engineers. As a result, the early units experienced problems in the field due to the durability of the components, manufacturing variations, and insufficient dealer training about service procedures. After the problems were solved, the Select-O-Speed transmission became a popular option for Ford tractors and remained in the line for many years.
Larry Gay is the author of four farm tractor books including A Guide to Ford, Fordson, and New Holland Tractors. This book may be obtained from ASABE at 800-695-2723 or www.asabe.org, click publications, click history books, click Ford.
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