This manual covers the 400 TRV, a versatile ATV designed for a variety of terrains and tasks. Featuring a 375cc 4-stroke, liquid-cooled engine with a carburetor fuel system, this model is equipped with an automatic transmission offering high and low range, and a 4WD drive system. Its robust construction includes double A-arm front suspension and a combination of double A-arm and swingarm rear suspension, supported by dual hydraulic disc front brakes and a single hydraulic disc rear brake. With a substantial ground clearance of 11 inches and durable AT25x8-12 front and AT25x10-12 rear tires, the 400 TRV is engineered for reliable performance and capability in demanding environments. This comprehensive service manual provides essential information for the maintenance and repair of your 2006 400 TRV. It details critical procedures, technical specifications, and troubleshooting guidance necessary for keeping your ATV in optimal condition. Within these pages, you will find instructions for routine maintenance, engine care, drivetrain servicing, and chassis component upkeep, including specific fluid recommendations such as SAE 10W-40 engine oil and antifreeze coolant. This resource is an indispensable tool for owners and technicians alike, ensuring the longevity and peak performance of your vehicle.