Among the new designs in group I, the lightest weight class, there were two 2.5 -ton 6x6 vehicles. When they were subsequently rolled out of the shops of the Hoiabird Quartermaster’s Depot in 1932, one, W3228, was powered by a Duesenberg J engine, while the other, W3229, was powered by a Lycoming. In time, a Franklin air-cooled V12 was also trialled in one of the vehicles.
It is worth noting that during this time, a certain AW Herrington was employed by the Motor Transport Division of the Quartermaster Corps. While the Standard Fleet did not enter mass production, the vehicles created were instrumental in defining future generations of US Army tactical vehicles. The Standard Fleet had been created with the purpose of crafting vehicles built to wholly military specifications using standardised components, as opposed to the previous process of buying commercial vehicles from a variety of manufacturers – vehicles that might have closely fitted military needs, but were rarely exactly what the US Army wanted. Ultimately however, Congress and the Comptroller General of the United States decreed that the Army could not produce its own vehicles as it had with the Standard Fleet, but rather had to rely on private enterprise for its future needs.
Although those with dual rear wheels faired better, the off-road shortcomings of two-axle vehicles, even 4x4s, were obvious. Accordingly, consideration was given to 6x6 trucks, and in 1933 the Army procured a commercial 2.5-ton 6x6. Designated the TL29-6, this truck was manufactured by the Indianapolis-based Marmon-Herrington Company, which had AW Herrington, no longer in the service of the Army, as one of its principals.
The TL29-6 was not without competition, as Corbitt offered the Army its 168-FD8.
These cars were a precursor to the famous CCKWX.