Q: How Can Wear in Universal Joints Be Checked?A: Universal joints are mechanical couplings that connect two rotating components that meet each other at different angles, composed of a yoke on each side connected by a crosspiece called a trunnion with needle bearings in cups at each end of the trunnion held together by snap-rings. Wear in the needle roller bearings is characterized by vibration in the driveline, noise during acceleration, and in extreme cases of lack of lubrication, metallic squeaking, and ultimately grating and shrieking sounds as the bearings disintegrate. To check for wear, try to turn the shaft with one hand while the other hand holds the rear axle flange or front half coupling, use a pry bar inserted into the gap between the universal joint and the driveshaft or flange, or attempt to lift the shaft and note any movement between the yokes of the joints. If any of these conditions exist, replace the universal joints with new ones.