If the U-joint fails while driving, you will lose control over your vehicle and it may tip over, leading to fatal accidents and irreversible damage. A broken U-joint may impair the brake line, the power transmission and other parts of the vehicle and can cause damage to the vehicle or the driver.Click to see full answer. Likewise, how do I know if my AU joint is bad? Symptoms of a bad U-joint Clunking noise when shifting into drive or reverse: By far the most common symptom of a bad U-joint is a loud clunking or banging noise when you put your car into gear. Vibration while driving: A worn U-joint will cause an axle or driveshaft to lose its balance. Furthermore, how much does it cost to replace AU joint? The average cost for a u-joint replacement is between $396 and $458. Labor costs are estimated between $97 and $123 while parts are priced between $299 and $335. Simply so, is a bad U joint dangerous? A bad u-joint can cause a clunking sound or jerkiness while driving, particularly when letting off of and pressing the accelerator. A bad u-joint can also cause vibration at certain speeds, emanating from the center or rear of the vehicle. If a u-joint is excessively worn, there’s an easy test you can perform.What happens if your drive shaft breaks while driving?A common symptom of a failing driveshaft is an intense shaking coming from underneath the vehicle. Worn out u-joints or bushings can cause the driveshaft to vibrate. If you don’t get the u-joints or bushings serviced, it can lead to further damage to other drivetrain components.