Eaton produces the 13-speed and 18-speed manual transmissions widely used in heavy-duty trucks.
These gearboxes are best known through Eaton’s Fuller and Roadranger heritage. Fuller Manufacturing was acquired by Eaton in 1958, and the resulting Eaton Fuller transmissions became familiar equipment in North American tractor-trailers. The RT-13 and RT-18 are examples of heavy-duty manual models designed for demanding commercial applications.
The extra ratios help a truck keep its diesel engine in an effective operating range while hauling heavy loads or climbing grades. A range selector and splitter allow drivers to access more ratios without requiring a separate conventional gear pattern for every speed. These transmissions are generally non-synchronized, so professional drivers may use techniques such as double-clutching or precise engine-speed matching.
A common mix-up is confusing Eaton with Cummins, Detroit Diesel, or Allison. Cummins is primarily associated with engines, Detroit produces engines and transmissions, and Allison is especially associated with fully automatic commercial-vehicle transmissions. Eaton also sells automated manual transmissions, but the classic 13- and 18-speed stick-shift units point to Eaton Fuller.