NOCTI Automotive Practice Test

A worn U-joint often shows up as a chirp or squeak when you start to move from a stop because the joint has loosened or dried lubrication. As the driveshaft begins to rotate and the joint takes on load for the first time, the worn bearing surfaces rub or bind briefly, producing a high-pitched sound. This startup noise is a telltale clue that the joint isn’t rotating smoothly under initial torque. Other symptoms like a vibration at highway speed can occur with U-joint wear, but they’re less specific. Noise when braking points to brake components, and an oil leak isn’t associated with a U-joint, since the joint is grease-lubed rather than oil-filled.