Part Notes: 4 Wheel Drive, 2500 With 10.5 Axle, Without Anti-Spin, 3.73 Ratio;4 Wheel Drive, 3.73 Ratio, Without Anti-Spin, 1500, 2500;Mega Cab, 4 Wheel Drive, 3.73 Ratio, Without Anti-Spin, 1500, 2500;Regular/Quad Cab, 4 Wheel Drive, 2500 With 10.5 Axle, Without Anti-Spin, 3.73 Ratio