Differential Cover Dana M226The Titan Shield: Extreme Protection for Your Nissan's Rear Axle. The Nissan Titan, Frontier, and Xterra are built on rugged platforms, often sharing the heavy duty M226 rear axle (a robust variant of the Dana 44). While this axle is capable of handling serious abuse, the factory stamped steel cover is its "Achilles' heel." A simple slide off a rock can peel the cover's lip, causing immediate fluid loss and potentially catastrophic gear failure. The