This manual covers the 2006 Arctic Cat T660 Turbo ST, a model representing Arctic Cat's advancement into the 4-stroke, turbocharged snowmobile market. Designed for touring and comfort, the T660 Turbo ST offers a blend of power and efficiency, building on Arctic Cat's legacy of performance and innovation. Its integrated turbocharger and intercooler system enhances power output, while the 4-stroke engine provides improved fuel economy. This model features a Continuously Variable Transmission (CVT) with forward and reverse, and incorporates advanced suspension systems like Arctic Wishbone AWS and ACT Rear Suspension, including adjustable air shocks. This comprehensive Workshop Service Repair Manual provides detailed information for all models, engines, trims, and transmission types. It is an essential resource for owners and technicians, offering step-by-step procedures for maintenance, diagnostics, and repairs. The manual covers a wide range of systems, including engine, fuel, electrical, drivetrain, track, brake, suspension, and steering. With hundreds of pages of detailed diagrams, critical specifications, and troubleshooting guides, it ensures thorough understanding and effective upkeep of the Arctic Cat T660 Turbo ST, enabling users to perform everything from routine checks to complete component rebuilds.