In basic passenger car design, the drive line connects the transmission with the driving axles. In effect, it transmits engine power to the driving wheels.
Ordinarily, the engine is mounted on the frame, and the driving wheels are free to move up and down in relation to the frame. In between, the angularity of the line of drive is constantly changing. This means flexibility is needed in the drive system and, usually, it is provided by universal joints. See Figs. 46-1 and 46.2.
