Street Series Rear Differential Cover Raw w/ Machined Fins GM Trucks 99-13aFe Power's new rear differential cover brings performance engineering to the protection of your axle's differential. This differential cover is constructed out of durable A356-T6 cast aluminum with reinforcing ribs for maximum strength. Mounting hardware is included for a hassle-free installation. A calibration plug set to the factory level prevents overfilling of the differential. A magnetic drain plug and a deep reach magnetic fill plug are provided for maximum protection. This cover has a raw finish with machined fins for a distinctive look. 4 Quart Gear Oil Capacity: This cover has about a 4 quart gear oil capacity at the factory fill level, factory cover holds about 3 quarts. Built-in External Fins: Built-in external fins transfer heat from the fluid to the outside air for maximum cooling. Magnetic Drain/Fill Plug: This system incorporates a magnetic drain and deep reach fill plug that captures loose particles for maximum rear-end protection. Oil Level calibration plug: A 1/8" NPT calibration plug is set to the factory fluid level which eliminates accidental overfilling. When it comes to engineering for power, performance, protection and value, aFe Power is the only choice.