GM Genuine Parts Automatic Transmission Valve Bodies are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These valve bodies act as a hydraulic brain, directing hydraulic fluid to different channels within the valve body in order to perform your vehicle's gear changes. GM Genuine Parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some GM Genuine Parts may have formerly appeared as ACDelco GM Original Equipment (OE).