Compared to Marvin Baumann's tractor, molasses moves at breakneck speeds. Marvin's 1951 8N "Fourtrans" is billed as "the slowest tractor in the world." How slow is it? Well, in the lowest gear, it travels nine feet per hour (or nearly two inches every minute).
The Fourtrans was created using a special purpose transmission and gear reduction units that were available for use in the N series tractors. They were not necessarily used in conjunction with one another, other than with the standard production transmission. The tractor was constructed to show the effects each transmission has on the operation of the tractor. Featuring 48 forward speeds, it is believed to be the world's slowest gear-driven tractor.
The transmission and gear reduction units used in conjunction with the four-speed transmission that is standard on the Ford 8-N include:
Sherman Over and Under Transmission. This transmission was used to add an overdrive as well as an underdrive to the standard transmission. That gives the tractor 12 forward speeds. It is mounted forward of the standard transmission. The shift handle is on the left side, under the steering column.
Auburn Trencher Gear Reduction Unit. This gear reduction unit was used when a trencher was mounted on the tractor. It has an 80-to-1 gear reduction to produce the slow speed needed to operate a trenching attachment. This unit is mounted directly behind the standard transmission and extends the tractor 9-3/4". The shift handle is located on top of the gear reduction unit, directly in front of the seat.
Howard Rotary Hoe Gear Reduction Unit. This unit has a 3.5-to-1 gear reduction to obtain the slow speed needed to operate a rotary hoe. This unit was made in England by Howard Rotary Hoe Ltd. It is a planetary gear system that is normally mounted directly to the rear of the transmission. In this tractor, it is mounted to the rear of the Auburn gear reduction unit. The shift handle extends out on the right side of the differential housing.
This tractor was constructed over a three-year period. The search for the various units went nationwide: The Sherman transmission was located in Iowa; the Auburn unit in Ohio; and the Howard unit – the rarest and most difficult to find – was located in Connecticut. The project was completed in June 1999.