Gear Gaurd EP 85W140 GL-5

It seems like you're referring to a specific type of gear oil: EP 85W140 GL-5, with the brand name "Gear Guard." EP stands for Extreme Pressure, 85W140 refers to the viscosity grade of the oil, and GL-5 is a gear oil specification.

Here's a breakdown of what each of these terms means:

EP (Extreme Pressure): EP oils are formulated to handle high-pressure and heavy-duty conditions, typically found in gearboxes and differentials. These oils contain additives that help prevent metal-to-metal contact and reduce wear under extreme pressure and high loads.
85W140: This is the viscosity grade of the oil. The "85W" indicates the oil's viscosity characteristics at lower temperatures, and the "140" indicates the viscosity at higher temperatures. In simpler terms, it means that this oil is thicker and better suited for heavy-duty applications and high-temperature environments.
GL-5: This is a gear oil specification established by the American Petroleum Institute (API). GL-5 oils are designed for hypoid gear systems, which are common in rear axles and differentials. They offer better protection against high-pressure conditions, oxidation, and corrosion compared to GL-4 oils.
Gear Guard: This appears to be the brand name of the gear oil you're mentioning. Different manufacturers produce gear oils under various brand names, and "Gear Guard" seems to be the brand associated with the EP 85W140 GL-5 gear oil you're referring to.