Mag-Hytec AA 14-12.0 Rear Differential Cover (2020-2024 6.6L Duramax, 2019-2024 6.7L Cummins)

Fitment

Fits the AAM 12.0 rear axle on 2020-2024 Chevrolet Silverado 2500HD/3500HD and GMC Sierra 2500HD/3500HD with the L5P 6.6L Duramax, and on 2019-2024 Ram 2500/3500 with the 6.7L Cummins. Our catalog tags list the L5P from 2017 on and the Cummins as 2019-current, but this cover's listed range is 2020-2024 Duramax and 2019-2024 Cummins, so verify fitment by VIN.

Ram 2500 owners, check your rear suspension first. Mag-Hytec's application note says Ram 2500 trucks with coil springs take part # AA 14-12 CS, not this cover.

Why this part

Mag-Hytec builds this cover to extend the service life of the gear lube in a heavy-duty rear axle. The fins machined into the outside of the housing act as heat sinks to dissipate heat. The 8-quart total capacity gives the gears more oil to work with than the stock cover. The magnetic drain plug holds wear metal out of circulation between services.

Service gets easier too. Check the level with the aluminum dipstick and flush the differential fluid without removing the cover. Since the cover stays on, there is no gasket to scrape between changes, and the O-ring gasket requires no sealant when it does go on.

What you get

• Mag-Hytec AA 14-12.0 finned aluminum rear differential cover
• O-ring gasket
• Bolt kit
• Magnetic drain plug
• Aluminum dipstick

Specifications

Part number: AA 14-12.0. Mag-Hytec's feature list:

• Bolt Kit Included
• 8 Quarts Total Capacity
• O-Ring Gasket Requires No Sealant
• Magnetic Drain Plug & Aluminum Dipstick
• Finned Aircraft Quality Aluminum Housing
• Flush Differential Fluid Without Removing Cover
• Limited Lifetime Warranty On Cover, 5-Year On O-Rings

Manufacturer warranty: Limited Lifetime.

Installation notes

Count the bolt holes and you will find 12, not 14. This is still the correct cover for the 14-bolt (12″) differential. Mag-Hytec removed the top and bottom bolt positions to make room for the drain plug and the temperature sending unit hole. The bolt kit is included, and the O-ring gasket seals without sealant.

About Mag-Hytec

Mag-Hytec works out of Van Nuys, California, building differential covers, deep transmission pans and filters for Cummins, Duramax and Power Stroke trucks. Their rear covers include the AAM 11.5 and AAM 12.0 used under Ram and GM heavy-duty diesels, and every unit is built around the magnetic drain plug the company is named for.

Frequently asked questions

Why does a 14-bolt cover have only 12 bolt holes?

Mag-Hytec removed the top and bottom bolt positions to make room for the magnetic drain plug and the temperature sending unit hole. It is the correct cover for the 14-bolt (12″) differential.

I have a Ram 2500 with coil springs. Is this the right cover?

No. Mag-Hytec lists part # AA 14-12 CS for Ram 2500 trucks with coil springs. Call us with your VIN if you are not sure which rear suspension your truck has.

What is the warranty?

Mag-Hytec backs the cover with a limited lifetime warranty and the O-rings for 5 years.

Questions on fitment? Call the shop at the number in the header. We install everything we sell.