If you need more protection for your front differential, consider replacing the cover on the Ford 7.3 transmission front differential. Look for covers made from die-cast A380 aluminum that also feature reinforced ribs. If the cover you choose doesn't come with a new O-ring, be sure to order it so the seal doesn't leak. On covers with built-in external fins, you get extra cooling since the fins transfer the fluid heat to the outside air. A magnetic drain plug grabs loose particles from the transmission so that they don't clog up the galleys. Another excellent feature is the oil level sight glass. This allows you to check the transmission oil without removing the fill plug. It also helps eliminate overfilling the transmission.