Two Pickups with more similarities, such as the body structure, ground shadow size, and height, than differences, like the powertrain, horsepower, starting price, and maximum occupancy. First of all, the 2017 Ram 1500 Crew Cab Diesel produces fewer horsepower than the 2017 GMC Sierra 2500HD Double Cab. Also, there is a $5,025 difference in the base MSRP. The 2017 1500 Crew Cab Diesel has a higher starting price than the 2017 Sierra 2500HD Double Cab. In addition, you'll seat one more passenger in the Sierra 2500HD Double Cab than in the 1500 Crew Cab Diesel. Among similarities are the body structure, ground shadow size, and height.