Axle Shaft Replacement
What is a front axle?
The front drive axle is responsible for transmitting power from the transmission or differential to the wheel hub. There are two types: straight axles and constant velocity (CV) axles.
How does the front axle work?
Front drive axles are made of strong metal in order to withstand transmitting power from the engine to the wheels and carrying the weight of the vehicle.
They have geared ends called “splines” that mesh with the differential and the hub-and-bearing assembly. Straight axles spin inside of a tube called the axle housing, which contains the differential in the center, the right and left axles, and the wheel bearings. Unlike a straight rear axle, the front axle must bend to allow the wheel to turn. This bending is accomplished using a universal joint.
Independent suspension vehicles use CV axles, which have articulating heads at both ends, allowing the wheel to move independent of the differential in all directions. The CV gears at the ends are enclosed in a thick rubber material, called the CV boot, that prevents grease from escaping and dust from entering.
CV axles have become far more common to see in modern passenger vehicles, while straight axles remain dominant in heavy duty applications.
A "clicking" noise when turning can be from a failing CV joint. In many cases, the CV axle shaft will need to be replaced.
What are the symptoms related to a bad front axle?
When a straight axle fails, it may cause vibration while driving. If the wheel bearing has failed, the axle and bearing will make a grinding noise while you drive. This may be accompanied by vibrations in the steering wheel and brake pedal.