ACDelco GM Original Equipment Automatic Transmission Differential Sun Gear is the drive gear within the final drive planetary gear set. As the center gear in final drive, it receives torque from the transmission and drives the planetary carrier in reduction. This original equipment transmission gear is manufactured to fit your specific GM vehicle and will provide the same performance, durability, and service life of your factory original equipment.Built to exacting specifications and extensively tested, ACDelco Transmission Components include GM Original Equipment and a select offering of premium aftermarket Professional Transmission Components for GM vehicles. Get peace of mind that the fit, form, and function are up to the high standards and specifications of General Motors. From transmission cooler lines and fittings to gaskets and valve bodies, with GM OE Transmission Components and ACDelco Professional Transmission Components, you can rest assured that your vehicle is receiving high-quality parts engineered for long lasting performance, durability, and dependability. ACDelco GM OE and Professional Transmission Components are engineered for virtually every model of GM car, light duty truck, and sport utility vehicles.