* Specific configuration: The truck's axle ratio, cab style (regular, extended, crew cab), bed length (short, standard, long), and optional equipment (like fifth-wheel/gooseneck hitches) all affect towing capacity.
* GVWR (Gross Vehicle Weight Rating): This is the maximum allowable weight of the truck itself, including passengers, cargo, and fuel.
* GCWR (Gross Combined Weight Rating): This is the maximum allowable weight of the truck plus the trailer it's towing.
Therefore, there's no single answer. To find the exact towing capacity for *your* specific 2007 GMC Sierra 2500HD Duramax, you need to:
1. Check the sticker: Look for the sticker on the driver's side doorjamb. This sticker lists the GVWR, GCWR, and the specific towing capacity for your truck's configuration.
2. Consult your owner's manual: This manual will also specify the towing capacities for your vehicle.
Without knowing your truck's specific configuration, I can only give a general range. A 2007 GMC Sierra 2500HD Duramax likely had a towing capacity somewhere between 12,000 and 17,000 pounds, but it could be higher or lower depending on the factors mentioned above. You must consult your vehicle's documentation to know for sure.
