Mag-Hytec Rear Differential Cover 01-12 Chevy Silverado & GMC Sierra 2500 3500 6.6L Diesel & 8.1L Gas w/ Full floating Axle 14-11.5 Overall height 3 5/8" Includes: Bolt kit, Drain Plug and Dip Stick. Capacity: 8 Quarts This cover is the correct cover for your 14 bolt-11.5 differential, even though there are only 12 holes. The top and bottom bolts have been removed for drain plug and temperature sending unit hole.