Kenworth T660 Service Manual | TruckManuals This is a great factory service manual for the Kenworth T660, which includes all the information as noted below. This manual comes to you in a secure log-on & password. A wonderful space saver, no longer do you need to find extra book shelf space for this service manual. Kenworth - Trucks, Tractor & Forklift Manual PDF, DTC Some KENWORTH Truck Service Manuals PDF & Wiring Diagram above the page. Kenworth is an American company that is part of a well-known group of Paccar companies, specializing in the production of truck tractors, as well as heavy trucks products of this company are characterized by the highest quality of assembly, as well as excellent performance characteristics.