During acceleration and braking, the universal joint components handle the effects of various loadings and rear axle windup. The universal joint operates efficiently and safely within the designed angle variations. The operational life of the joint may decrease when you change or exceed the design angle.
Universal joints have needle roller type bearings. Round bearing cups hold the needle rollers in place on the trunnions. Snap rings or injected plastic hold the bearing cups in the yokes. The OEM lubricates the universal joints for life. You cannot lubricate the universal joints.