 The gearbox is considered the main problem, as earlier attempts by others failed due to the lack of suitable transmissions that could stand the torque long enough.After winning the 12 Hours of Sebring in 2006 with their diesel-powered R10 TDI, Audi obtained the overall win at the 2006 24 Hours of Le Mans, too.This is the first time a sports car could compete for overall victories with diesel fuel against cars powered with regular fuel or methanol and bio-ethanol.