PML Rear Differential Cover for Dodge/GM Trucks- AAM 11 1/2" Ring Gear, 14 Bolt, - Black Finish This cover provides greater oil capacity over the stock cover for cooler running temperatures. 3/16 inch thick wall construction adds strength to the differential housing Sand Cast Aluminum Construction with Raised Fins to dissipate heat Machined gasket surface for a secure seal using RTV or factory reusable gasket Oil changes without removing the cover.