What is a U Joint?
U joints, or universal joints, are the flexible connection points along the rigid bars of the drive shaft and they are an important part in the system that makes your vehicle go.
Components of a U Joint
U joints are steel X's with a bearing cap on each end that connects two straight rods and provides some flexibility while maintaining strength and connection. In most cases, u joints connect the rod coming out of the transmission to the drive shaft and the drive shaft to the rear differential, allowing the transfer of power from the engine to the wheels. A vehicle driving down even the smoothest road is going to experience changes in the angle between the transmission and the differential so a rigid connection is going to strain that rapidly spinning system, and if that connection is damaged or worn then there is a possibility for expensive (or even dangerous) consequences.
Adding Driveline Flexibility
This is where the U joints come in. By putting a few joints in that driveline the front and rear of the vehicle can tilt and shift independently of each other and the driveline will adjust and continue to function. As you can imagine this is a rough job and the u joints take a lot of punishment, but they are vital to the operation of the driveline and if the u joints are not functioning properly then there is potential for serious and expensive damage.
