While American innovators were experimenting with converting Ford trucks to four-wheel-drive as early as the 1910s, and largely for exploration or farming purposes, over in Europe there was a pressing need to convert to four-wheel-drive as many trucks as possible for the impending war. Enter DAF.
In the latest issue of the American Truck Historical Society’s excellent publication, Wheels of Time, John Bodden wrote on DAF’s late 1930s conversions of two-wheel-drive Ford and GM trucks into both four-wheel-drive and six-wheel-drive vehicles, mostly for the Dutch military, in what was possibly one of DAF’s first moves away from building just the trailers that figure into the company’s name and toward full vehicle production.
The four-wheel-drive conversions were aimed at retaining the Ford and GM front axles and suspensions, making the conversions less complicated and less expensive than contemporary conversions, which scrapped the axles and suspensions for entirely new setups. To do so, DAF engineers developed a transfer case, as normally used on four-wheel-drive conversions, but one with dual forward outputs – one aimed at each front wheel. Individual diagonal driveshafts then transferred power to bevel-drive gears that replaced each front hub. Bodden didn’t mention in the article how the system coped with turning the wheels – whether the driveshafts extended and compressed or whether the transfer case somehow pivoted in response – but he did note that the transfer case had no inter-axle differential.
The drive system was said to be cheaper to install than the Marmon-Herrington, with which we are familiar. It also enjoyed a shorter life than the Marmon, and had a peaceful death.
The six-wheel-drive conversions similarly were designed to make use of the stock axle. In a setup we’d see echoed in John Kopczynski’s elliptical-wheeled tractor/jeep designs, DAF engineers mounted to the ends of the original rear drive axle a hollow walking beam tandem suspension which contained driveshafts to bevel gears at each outer end. (Kopczynski wasn’t even that insane; he just used chains to transfer power.) Bodden noted that DAF completed more than 1,000 such conversions.
The drive axle was suspended by longitudinal leaf springs, so this entire mechanism was fully articulated. Though somewhat suggestive of the Hendrickson walking beam design, it was far more loosey-goosey, with neither torque rods nor the stout (read: hard riding) heavy springs or rubber biscuits of a Hendrickson.
Many other six-wheel-drive conversions, such as the much earlier Renault six-wheelers, simply employed a second rear axle and some method of slinging power back to the third axle from the second.
DAF, as we know, survived the war and went into full truck production in 1949. The innovative Variomatic transmission and DAF automobiles followed in 1958. Bodden notes that DAF, which is now a subsidiary of Paccar, today employs much more conventional drivelines.
