2020-2026 3.0L Duramax 9.5" SU8 12-Bolt Heavy-Duty Cast Aluminum Rear Differential Cover (1380514X0)

PPE's heavy-duty rear differential cover is built for the AAM 9.5" 12-bolt rear axle with RPO build code SU8, found under 2020-2026 GM 1500 trucks including the 3.0L Duramax. It is cast from heat-treated A356.0-T6 aluminum, adds 0.57 quart of fluid capacity, and uses half-inch external cooling fins to pull heat out of the gear oil so it holds its viscosity when you tow or haul.

Inside, precision-placed windage scrapers keep fluid flowing over the gears without excess churning, which cuts heat buildup, aeration and parasitic loss. The internal scrapers and external fins form a cross-braced structure, and cast-in gussets add support at the housing flange. The fill plug sits at the factory fill height, and both 304 stainless service plugs carry a high-temperature neodymium magnet to catch ferrous wear particles.

Part Number: 1380514X0

• Heat-treated A356.0-T6 cast aluminum, strong and thermally conductive
• Precision-cast in permanent steel molds for a smooth, consistent finish and accurate fit
• Adds 0.57 quart of fluid capacity for more thermal headroom
• Half-inch external fins improve heat dissipation and impact resistance
• Internal windage scrapers reduce churning, heat, fluid aeration and power loss
• Fins and scrapers combine into a cross-braced structure
• Cast-in gussets support the differential housing flange
• 304 stainless drain and fill plugs with neodymium magnets and Viton O-rings
• Available in Raw, Brushed and Black finishes

• Fits AAM 9.5" rear axles with RPO build code SU8 only. Check the Service Parts Identification label in the glove box before ordering.
• Not compatible with SU7 axles. For SU7, see the GM 9.5"/9.76" Rear Differential Cover (138051200).
• OEM P/N reference: GM 85586188 (replaces 23243722, 84553988).

Click Here

Don't see your question? Ask us anything about this product.