9.5"-12 Bolt Heavy-Duty Cast Aluminum Rear Differential Cover (Brushed)

Features:

• A356.0-T6 heat-treated cast aluminum
• Brushed cast aluminum finish
• Adds 0.57 quart of fluid capacity
• Half-inch external cooling fins
• Internal windage scrapers reduce churning and heat
• Cross-bracing structure improves rigidity
• Cast-in gussets add flange support
• 304 stainless plugs with neodymium magnets
• Viton O-rings on service plugs
• Fill plug set at factory fluid level
• Made for 3.0L Duramax Silverado and Sierra 1500
• For 9.5"-12 bolt axles, build code SU8

A Brushed Aluminum Cover That Protects The Gears As Good As It Looks

Most upgrades either look better or work better, and this rear differential cover is built to do both for your Duramax powered Silverado or Sierra 1500. The brushed aluminum finish gives the back of your axle a clean, finished look. Underneath that finish, PPE has designed the cover to deal with the problem that wears differentials out, which is heat. According to PPE, excessive heat breaks down the protective qualities of the fluid and speeds up wear on the gears and bearings. This cover holds 0.57 quart more fluid than the factory cover, and PPE says the extra volume gives the system more thermal capacity. Half inch fins on the outside carry heat away from the housing, and scrapers on the inside keep the fluid from churning and building more heat. Magnets in both service plugs catch the metal particles that circulate in the fluid, so they stay away from the gears. For a diesel half ton that tows and hauls, this is an upgrade that adds protection and some good looks to a part that most people never see.

Permanent Mold Casting And Cast In Gussets Add Strength Where The Housing Needs It

This cover is built for the AAM 9.5 inch, 12 bolt rear axle with build code SU8, found on 2020-2026 Silverado and Sierra 1500 trucks with the 3.0L turbo diesel Duramax. PPE casts it in permanent steel molds from A356.0-T6 heat treated aluminum, a high strength material that conducts heat well, and finishes it brushed. The permanent molds give a smooth, consistent surface with high dimensional accuracy, according to PPE. Half inch external fins improve heat dissipation, lower the fluid temperature, and add impact resistance. Inside the cover, precisely placed windage scrapers reduce churning, which PPE says cuts heat generation, fluid aeration, and power loss. The fins and scrapers combine into a cross bracing structure, and cast in gussets give the differential housing flange extra support and rigidity. Both service plugs are 304 stainless steel with high temperature neodymium magnets and Viton O rings, and the fill plug sits at the factory fluid level. PPE lists the GM OE reference as 85586188, which replaces 23243722 and 84553988, and directs SU7 axle trucks to part 138051200.

Fitment: 2020, 2021, 2022, 2023, 2024, 2025, 2026 GM Silverado/Sierra 1500 3.0L I6 Turbo Diesel Duramax, AAM 9.5"-12 bolt rear axle, build code SU8 only

Notes:

• For 3.0L Duramax Silverado and Sierra 1500 trucks with the AAM 9.5"-12 bolt rear axle and build code SU8 only, confirm your axle build code before ordering
• Not compatible with AAM 9.5" rear axles with build code SU7, PPE directs SU7 trucks to part 138051200
• Brushed finish, raw (138051400) and black (138051420) versions are sold under separate part numbers
• Adds 0.57 quart of fluid capacity over the stock cover
• GM OE reference 85586188, which replaces 23243722 and 84553988
• Fill plug is positioned at the factory fluid level, both plugs are 304 stainless steel with neodymium magnets and Viton O-rings
• Heat, wear, and fluid temperature benefits are manufacturer statements, results will vary
  

Install Instructions