Automotive grease is a semi-solid lubricant used to reduce friction and wear between moving parts not continuously bathed in oil. Common applications include chassis lubrication, wheel bearings, constant velocity joints, and ball joints. Formulations vary based on base oil, thickener type (lithium, calcium, etc.), and additive packages to withstand specific operating temperatures, loads, and environmental conditions. Key properties include shear stability, water resistance, and oxidation resistance, indicated by NLGI grades denoting consistency and load-carrying capacity. Specialized greases are available for high-temperature, extreme pressure, or synthetic applications, denoted by API service classifications. Proper grease selection ensures component longevity and operational performance.