A customer may elect to use an Extreme Pressure (EP) lubricant; however, Amarillo Gear Drives do not need the EP additives to operate properly.  In fact, EP additives will prevent our optional sprag non-reverse devices from properly functioning.
In the past, data from bearing manufacturers had suggested that EP lubricants might extend bearing life. At that time, we recommended EP lubricants in gear drives without a sprag-type backstop.  However, current research indicates that some EP additives may reduce bearing life as evidenced in recent bearing manufacture’s testing when water and humidity are present. Most EP additives include sulfur, and when in contact with water molecules, will become an acidic pH that is corrosive and reduces bearing life. Because Amarillo Gear has a long history of gear drives in service using non-EP oils, we conservatively decided to take EP oils out of our O&M Manual.