2007 -2010 Chevrolet Express Silverado GMC Sierra Savanna 3500HD DRW Dually Rear Axel Assembly 3.73 Ratio Cab and Chassis Measurements Backing Plate To Backing Plate 60" Center Leaf To Center Leaf 49"Calibers Facing Front w/ Yoke OPT Code: GT4 Shock Absorber Mounts Not Staggered Commercial Application