Dive Into 100's of Accessories for your 2004 GMC Sierra 2500 Truck. We feature An Excellent Selection of of accessories for your 2004 GMC Sierra 2500. Examine performance, interior and exterior accessories from all the top brands. Equip your GMC Sierra 2500 Pickup and get Free Shipping a Low Price. Plus, if you need help finding the best accessory for your GMC, our product specialists are available to help you 7-days a week.