Universal joints, also known as U-joints, are key components of the driveshaft of rear- and four-wheel drive vehicles. When this important part of the driveshaft fails, you will have a multitude of signs and symptoms that you may not be able to diagnose.
In this article, I go over the most significant symptoms of a bad universal joint and what it will cost to replace it. First, let’s look at the signs of a bad universal joint to be aware of.
Symptoms Of A Bad Universal Joint (U-Joint)
The most visible symptom of a bad universal joint is vibration in your car at higher speeds. However, it can also cause clunking or squeaking noises while driving, and in extreme cases, damage the seals which cause the transmission to leak.
Here is a more clear and descriptive explanation of the signs of a bad or failing U-joint:
#1. Squeaking Noise.
Every universal joint bearing parts are greased when it is installed on your vehicle. Based on the number of miles you have on the vehicle, the grease may no longer be lubricating the bearings.
The grease tends to evaporate or work its way out of the bearing cup as the U-joint twists with the driveshaft.
When the bearing becomes dry, contact is made between the metal surfaces, and that will cause a squeaking noise.
This is most prevalent in the drive shaft rotation, so it will be most noticeable when you start to move, either forward or backward.
Once you get over five to ten mph, you may stop hearing the squeaking because it is drowned out by the other noise of the vehicle.
#2. Clunking Noise.
U-joints can also make noises besides squeaking. You might hear clunking accompanied by a ringing noise when you put your vehicle in reverse out of Drive.
It means the U-joint bearings are loose enough while driving, but when you shift to reverse, they bind up.
If you heard the squeaking noise in the past and have not greased the bearings, it is likely that this is the next phase you could take. You could add grease at this point to slow down the failure of the bearings,
#3. Vibration.
If you feel a vibration while driving forward, it means the U-joint bearings are worn down to the point that the driveshaft can rotate beyond its normal range of rotation. This is creating vibration and imbalance.
You will notice that the vibration is worse than if a wheel was out of balance because the driveshaft rotates three to four times faster than the wheels do.
The bad U-joint is generating damage to other major parts like the transmission. If you want to prevent damage to other parts, you must replace the U-joint.
#4. Transmission Fluid Leak.
A transmission fluid leak can be from a worn universal joint (U-joint) and will come from the back of the transmission in a worn U-joint situation.
Typically, a leak only occurs when these other problems have been ignored. As the U-joints wear, more damage is done to the transmission tail shaft bushing, which damages the transmission output shaft seal and allows fluid to seep through.
This means that you will be looking at a more expensive repair than just replacing the worn U-joint.
#5. Unable to Move Vehicle.
If you’ve seen a truck on the side with a driveshaft sittin there, I bet it was somogute the U-joint forgat for weeks before it failed.
You can’t imagine what will happen if you don’t fix a U-joint when it starts causing problems. You could end up with a complete extraction of the driveshaft.
Once the driveshaft falls off, it simply won’t transfer any power to the rear wheels. There will likely be more wrong with your vehicle than just the U-joint; you might need an entirely new driveshaft instead!
Location of Universal Joint (U-Joint)
The universal joint is part of driveline components. There are two U-joints on a rear-wheel vehicle, one closer to engine and the other at rear differential. However, a four-wheel drive vehicle will use more U-joints, and its driveline.
Front-wheel drive will not use U-joints; these vehicles will use two constant velocity (CV) joints, and allows for some compensation when steering.
The Function of a Universal Joint (U-Joint)
The U-joint will provide a connection for the driveshaft to the differential. If you are using a U-joint that is acting as a connection for two driveshafts, it will compensate for any misalignment as well.
The U-joint will use a cross-shape and have a bearing on each end, which allows for lateral and side-to-side movement from the driveshaft.
The U-joint allows for slight positional changes between the differential, transmission, and driveshaft. While the U-joint can remain attached between the transmission and differential, a static connection cannot remain.
It will compensate for the independent motion of the vehicle on any terrain, as the differential and transmission will not stay in alignment with one another. While the U-joint compensates for motion, the driveshaft will stay attached and be able to spin freely.
Universal Joint (U-Joint) Replacement Cost
Typically, a U-joint replacement will cost between $225 to $400 on average. Labor costs should be between $100 to $200, and the parts are approximately $125 to $200.
The prices will vary based on the make and model of which vehicle runs. If you are mechanically skilled and have the tools, replacing your own U-joints can be done.
What does a universal joint sound like when it is bad?
If your universal joint is bad, you may hear a squeaking noise or clunking noise underneath the car. However, a bad U-joint sometimes may be silent, and you may notice it by vibrational feelings when accelerating and higher speeds.
Can you drive with a bad universal joint?
No. It is unadvised to drive a car with a bad universal joint. If the U-joint is bad, it will put stress on the transmission parts and lead to other expensive repair costs, so you should fix it as soon as you notice it.
How long do u joints usually last?
U-joints are designed to last the entire lifespan of a car and many car models never need to be replaced.
How long they will last is dependent on how you drive the car, maintenance and also what type of car it is. Unless you drive aggressively and/or the car is of better quality, expect a U-joint to last over 100,000 miles for the majority of car models.
What is the most common cause of universal joint failure?
The most common cause of U joint failure is the lack of maintenance or just age alone. U-joints should be greased often between the range of every 20,000 to 40,000 miles (or as recommended by the manufacturer).
If the U-joint is manufactured poorly, it will break the gasket and dry up, which would cause the failure to happen.