Difference Between Shaft and Axle in Automobile.?

Shaft is a mechanical element that transmit power and torque moment. Usually shafts are the elements with gears and pulleys attach on them (power transmission). The axle on the other hand is a mechanical element that does not transmit power. It can rotate or it can stand still. It is only loaded with bending moments.

In vehicles, the terminology is same. The shafts that transmit power to the wheels are called drive shafts. The driven wheels have axles. Some people like to call the drive shafts axles (or half axles), from where the confusion can occur. The right term is drive shafts.

One states that "true" axles are merely static rods that support rotating members, and only shafts transmit power and motion. Another defines an axle as any wheel support, whether or not it transmits power and motion, while a shaft accepts and drives gears, pulleys, sprockets, and other rotary power elements