We could advertise a larger capacity, but we chose to only market usable capacity to set honest and reasonable expectations for our customers. The Titan XXL tank also features minimal hang down below the bottom of the stock tank (approximately only 2").Application. For model year: 2001-2010. For 2500HD and 3500HD Models with Duramax Engines. For use with diesel fuel ONLY. Additional Details. The TITAN tank is 26 gallons larger at 52 gallons. The stock tank is only 26 gallons. Will not interfere with powered steps, air bag systems. Our mid-ship, direct replacement fuel tanks are designed to use your trucks stock/OE sending unit. However, our tanks are compatible with Fleece, AirDog, FASS, etc. The "LB7 Kit" is required on all 2001 to 2003 General Motors trucks. On 2004 models it is required if the eighth character in the VIN is a "1".