One of the most common failures of a bolted joint assembly is the self-loosening induced by transverse cyclic loading caused by relative movement or vibrations. Self-loosening of bolted joints is a phenomenon that is present in all types of structures used in different industries including automotive, aerospace, and oil and gas. This phenomenon can cause catastrophic failures that result in loss of revenue, maintenance, accidents and health issues, and environment damage. The objective of this project is to investigate the loosening process using a rig that applies transverse vibration to a bolted connection. Fasteners of various thread type and size are tested to determine the effects on the loosening process. Loosening curves that display loss of preload over number of cycles are vibration are constructed to visualize and analyze the loosening process.