Royal Purple's Max Gear Oil is an ultra-tough, high-performance hypoid gear oil designed to provide maximum protection to heavily loaded gears while maximizing power throughout the drive train. It outperforms ordinary gear oils by combining the highest quality synthetic oils with proprietary Synerlec additive technology. This formula makes gears run smoother, quieter, cooler, and longer without overhauls, providing a significant reduction of drag in the drivetrain—a major advantage for trucks and other 4-wheel drive vehicles.