To find the exact towing capacity for *your* specific 2004 Silverado 3500, you should:
* Check the sticker: Look for the sticker on the driver's side doorjamb. This sticker will list the maximum towing capacity for your truck.
* Consult the owner's manual: Your owner's manual will have a section detailing towing capacities for different configurations.
Without knowing the specifics of your truck, I cannot provide a reliable towing capacity figure.