Industrial gear oils are used for power transmission, change speed and torque, change direction of rotation and axis of transmission. The lubricant at the gear boxes provides two primary benefits: to lubricate the teeth and to remove heat generated from the gear operation. The lubricant is also often used for lubricating the various bearing found in the gear box. If the correct lubricant is selected for use in a gear system it will provide slip-free power transmission at high mechanical efficiency, with good reliability, low maintenance and long life. Market tends to produce smaller and lighter gear boxes which make more critical the purpose to remove heating of the metal parts. In addition, gear boxes producers tend to prolong its operation life. For these reasons, providing high performance lubricants to the gear boxes is getting more relevant.