GM Truck 12-Bolt Alum Rear Cover.

The GM Truck 12-Bolt Aluminum Rear Cover from Moser Engineering is a premium sealed differential housing solution designed for serious truck builders and daily-driven performance vehicles. If you're running a 12-bolt rear end in a GM truck platform and want to eliminate fluid seepage, reduce maintenance hassles, and protect your drivetrain investment, this aluminum cover delivers both functionality and durability.

Machined from lightweight aluminum, this rear cover combines weight savings with superior heat dissipation compared to cast iron alternatives—critical for trucks that tow, race, or operate in demanding conditions where differential temperatures spike. The aluminum construction resists corrosion and reduces unsprung weight at the rear axle, improving handling dynamics while maintaining a solid seal. At 8.4 lbs, the lightweight design makes installation straightforward without sacrificing structural integrity.

This Moser Engineering cover is ideal for truck owners upgrading to aftermarket gears, those installing custom differentials, or anyone looking to eliminate leaks from worn OEM covers. Installation pairs seamlessly with any 12-bolt differential swap—stock replacements, limited-slip, or custom differentials—ensuring a proper fitment to GM 12-bolt housings with no modifications required to the axle or backing plate.