 The "jamming" sound came from the unsynchronised transmissions, where double-clutching was required to shift gears prior to a 1989 retrofit that added automatic transmissions.The White Motor Company Model 706 chassis with a White 16A 6-cylinder engine and body by Bender Body Company outperformed its competition during a group test at Yosemite National Park in California in 1935, leading to that model's selection by the National Park Service.The distinctive vehicles, with roll-back canvas convertible tops, were styled by noted industrial designer Alexis de Sakhnoffsky, with credit for mechanical design to F.W.