CV Joints: A Very Underappreciated Component of a Vehicle

Pictures throughout are damage caused by a failed CV joint.

Did you know that your vehicle has CV joints? If you did not, now is a good time to learn about them. Most vehicle owners try their best to make sure that their engine and transmission are running well, but when is the last time you heard someone mention their CV joints? More than likely, never. CV joints, technically known as Continuous Velocity joints, are some of the most complex parts of your vehicle that are quintessential to its performance and reliability. This is especially important with the different driving terrains Alberta has, from highways to gravel roads, to lots of turns and hills. You will want to be sure that your CV joints are working and properly maintained to keep your vehicle safely on the road.


CV joints allow components of the drive-train to flex, turn, and move naturally without disrupting power delivery or upsetting the vehicle.  CV joints are called Continuous Velocity joints because they maintain the velocity of wheel and axle rotation, no matter what angle the axle or wheels have. If you are turning, the CV joints allows for continuous power delivery even though the wheels are at an angle. CV joints also allow for continuous power delivery when your vehicle is traveling over a bump or pothole where the axles and driveshaft must move to accommodate the bad road quality.


The most common types of CV joints are Rzeppa joints, Cardan Joints, and Thompson couplings. Though they are all mechanically different, they all do the same thing. More simple CV joints, Cardan joints and Thompson couplings for example, are more common in diesel trucks and large vehicles. These joints have an open construction where the parts are all physically attached together to allow the angle of the driveshaft to change and rotate without the need of any special lubrication. Rzeppa joints, common in economy vehicles, are more complex as they use multiple ball bearings, an inner grooved ball, a grooved cup for ball bearings, and a boot to hold lubrication grease in order to deliver rotational energy.


The one thing that all of these continuous velocity joints have in common is the necessity of maintenance. When CV joints go bad, they usually produce whining, clanking, or squeaking sounds that are more prevalent at low speeds. Similar to wheel bearing problems, bad CV joints can cause a vehicle to pull and or vibrate violently. In some cases of CV joint neglect, the joints can break and allow the axle or driveshaft to rotate freely under the vehicle. Though rare, these occurrences can cause thousands in damage as the shafts are free to rotate and destroy suspension components, wires, fuel lines and brake lines. Though very rare, violent vibrations caused by a neglected joint can cause fasteners to become loose, transfer cases to crack, and transmission cases to crack.


One dramatic example we have seen recently was a situation where a front drive shaft exploded at 100 kilometers per hour and destroyed the transfer case. Unfortunately, the owner of the vehicle ignored the indicators of the problem, and the result was a very dangerous high speed failure, and thousands of dollars in repairs. More severe cases we have seen resulted in over $10,000 worth of damage from fuel lines, brake lines, wiring harnesses, and even the bottom of the cab floor being destroyed.


Never neglect your CV joints. Next time you take your vehicle in for an oil change or regular service, make sure you ask your mechanic at XL Mechanical about the health of your CV joints, as we check them as a courtesy during this service. They are relatively cheap and are easy to rebuild or replace, compared to the massive damage and loss of control possible at highway speeds if neglected. Save yourself time and money by simply maintaining your CV joints properly.