Sprags are also known as one-way clutches. They lock one one direction but freewheel when turned the opposite direction. (similiar to a bicycle, it freewheels pedaling backwards but locks pedaling forward) We stock sprags for most applications. We also incorporate heavy duty designed sprags in our transmissions. They are an aftermarket item that even OE doesn’t know about or use. When sprags wear out, the transmission may “slip or “shudder” in a particular gear.