Which of the following is NOT a fundamental unit of a universal joint assembly?

The correct answer identifies the Cross Carrier as not being a fundamental unit of a universal joint assembly. A universal joint, often used in driveshafts, consists of key components that allow for the transfer of rotary motion while accommodating angular misalignment. The fundamental units typically include the yoke, which houses the joint and provides a strong attachment to the driveshaft or other components, and the cross shaft, which connects the two yokes and allows for the rotational movement to occur.

Ball bearings, while not a primary structural element like the others, can be present in various designs to reduce friction and wear in moving parts, but they are not universally required for all types of universal joints. The Cross Carrier is not a recognized primary component within the standard assembly of a universal joint; thus, it would not be categorized as a fundamental part of the joint.

Understanding the standard components helps in recognizing how universal joints function and their role in mechanical systems, as the correct functions and relationships of these elements are critical for performance and reliability in machinery involving rotational systems.