Symptoms of a Bad or Failing Universal Joint (U-Joint)

Universal joints (“u-joints” for short) are components of the driveshaft assembly fitted to most rear-wheel drive trucks, four-wheel drive trucks and SUVs, or off-road vehicles. U-joints, which are found in pairs on the driveshaft, compensate for the height misalignment between the transmission and the rear axle, all the while transferring power to move the vehicle. This allows each end of the driveshaft, and its associated universal joint, to bend with each rotation of the driveshaft in order to handle the misalignment (as a side note, rear-wheel drive cars now mostly utilize constant-velocity joints for the same purpose, which permit far smoother flexibility of drive shaft rotation).

Here are some symptoms of a bad or failing universal joint you may notice, in approximate order of severity:

1. Squeaking noise when starting to move (forward or reverse)

The bearing components of each universal joint are greased at the factory, but may not have a grease fitting to allow further lubrication after the vehicle is put into use, limiting their service life. Since the bearing portion of each universal joint twists a small amount with each rotation of the driveshaft (but always in the same location) the grease can evaporate, or be thrown out of the bearing cup. The bearing becomes dry, metal-to-metal contact is made, and the u-joint bearings will squeak as the drive shaft rotates. The squeak usually cannot be heard once the vehicle moves faster than 5-10 mph because of other vehicle noise. The squeak is a warning that the universal joint should be serviced by a professional mechanic. You can certainly extend the life of your existing u-joints by doing so.

2. “Clunk” with a ringing sound when shifting from Drive to Reverse

This noise usually indicates that the universal joint bearings have enough excess clearance to allow the driveshaft to rotate slightly, then come to a hard stop, when power is reversed. This can be the next stage of deterioration after having insufficient grease in the u-joint bearings. Servicing, or greasing the u-joint bearings, won’t reverse damage to the u-joint, but may extend its life somewhat.

3. Vibration felt throughout the vehicle while moving forward at speed

This vibration means that the universal joint bearings have now worn enough to allow the driveshaft to move outside its normal rotational path, causing imbalance and vibration. This will be a higher frequency vibration than that of an out-of-balance wheel for example, since the driveshaft turns 3-4 times faster than the wheels. The worn universal joint is now causing damage to other components of the vehicle – including the transmission. Replacement of the universal joint by a professional mechanic is certainly in order at this point to prevent further damage. Your mechanic should, when possible, select quality replacement u-joints with a grease fitting, allowing for long-term preventative maintenance, and enabling extended life of the u-joint bearings.

4. Transmission fluid leaks from the rear of the transmission

Transmission fluid leaking from the rear of the transmission is often the result of a badly worn universal joint. The vibration noted above has now worn the transmission tailshaft bushing and damaged the transmission output shaft seal, which then leaks transmission fluid. If fluid is suspected of leaking from the transmission, the transmission should be inspected to determine the source of the leak, and the appropriate repair made.

5. Vehicle cannot move under its own power; driveshaft dislocated

You've probably seen it before: a truck on the side of the road, with the drive shaft lying under the vehicle, no longer attached to the transmission or rear axle. This is the ultimate failure mode for a universal joint – literally breaking, and allowing the drive shaft to drop to the pavement, no longer transferring power. Repair at this point will include much more than the universal joint, and may require full driveshaft replacement or more.


Next Step

Schedule Vehicle Drivetrain Inspection

The most popular service booked by readers of this article is Vehicle Drivetrain Inspection. Once the problem has been diagnosed, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. YourMechanic’s technicians bring the dealership to you by performing this job at your home or office 7-days a week between 7AM-9PM. We currently cover over 2,000 cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent Vehicle Drivetrain Inspection reviews

Excellent Rating

(146,098)

Rating Summary
136,734
5,133
1,039
737
2,455
136,734
5,133
1,039
737
2,455

Eliud

22 years of experience
109 reviews
Eliud
22 years of experience
Ram 1500 - Vehicle Drivetrain - Snellville, Georgia
Eliud was punctual and knowledgeable about my vehicle. Solved the issue within the half hour

William

16 years of experience
92 reviews
William
16 years of experience
Jeep Grand Cherokee - Check Engine Light is on - Denver, Colorado
Couldn’t be happier with my experience with William. Will happily recommend him to everyone and will definitely be using him again. Fantastic service.

Robert

31 years of experience
191 reviews
Robert
31 years of experience
Toyota Prius - Oil Change - San Jose, California
Rob was amazing and I will definitely request him for my next service. Great customer service, not only showed up on time but was early, didn't pressure me to rush out when he was finished, and explained his recommendations but did not try to push them on me. Everyone in and around San Jose should use him if he is not already booked!

Bret

41 years of experience
54 reviews
Bret
41 years of experience
Audi A6 Quattro - Car is not starting - Benicia, California
He is definitely a mechanic that I will using

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

How a Cable Clutch System Works
If If you drive a car with a manual transmission, you know that to get your car moving, you depress the clutch pedal, choose a gear, and then give the vehicle a bit of gas. But have you ever wondered...
How Long Does a Transmission Speed Sensor Last?
The The transmission speed sensor measures the RPMs of the shaft of the transmission. While the engine is running, but not moving, then the input shaft of the transmission is not moving either. When the input shaft moves, the transmission...
3 Essential Things to Know About Your Car’s Gear Shifter
The The gear shifter allows the vehicle to be put into different gears on a manual transmission. In an automatic transmission, the gear shifter is known as a gear selector. The gear shifter is normally located between the two front...

Related questions

Car won't shift into next gear when driving downhill

If the transmission operates normally in all other driving conditions this sounds like a feature in the transmission program to inhibit upshifts to prevent a runaway condition when going downhill in case the driver is towing or a hauling heavy...

Transmission locked, and car won't start

Hi. If your transmission is locked, and the car is unable to start, then there could be many possible problems. Anything ranging from a dead battery, to a faulty brake light switch can cause these types of symptoms. I would...

Transmission slipping, gear warning on the dash

Hello. Let's hope that you don't have an issue with the mechanical aspect of the transmission on your 2002 BMW 330xi. I believe the best thing to check will be the transmission fluid. Also, I suggest having a technician run...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com