RADHLBNIU Rear Main Seal Kit for Chevy/GMC/Cadillac 4.8–6.2L V8 — Die-Cast Aluminum Cover & Gasket

This rear main seal kit is designed as a direct-fit replacement for multiple GM trucks and SUVs, offering a robust aluminum cover, updated seal design, new gasket and all required installation hardware. It replaces OEM part numbers 635-518, 12633579 and 12639250 and fits a range of 4.8L, 5.3L, 6.0L and 6.2L engines. Before ordering, verify your vehicle’s year, model and engine to ensure proper compatibility.

Which vehicles and engines will this rear main seal kit fit?

This kit covers many model years across Chevrolet, GMC and Cadillac full-size trucks and vans. It lists specific model-year combinations where the kit has been engineered to match factory mounting points and crankshaft dimensions.

• Chevrolet: 2012–2013 Tahoe, 2012–2013 Suburban 1500, 2013 Silverado 1500, 2012 Express 1500, 2014 Silverado 2500 HD, 2014 Express 2500, 2012/2013/2014/2018 Express 3500, 2012 Avalanche.
• Cadillac: 2012 Escalade ESV.
• GMC: 2013 Yukon, 2013 Sierra 1500, 2015 Sierra 2500 HD, 2012/2014/2015 Savana 3500.
• Engine types: fits 4.8L, 5.3L, 6.0L and 6.2L applications listed above.

How does this kit prevent oil leaks and improve longevity?

The kit uses a die-cast aluminum cover paired with an updated seal profile, helping maintain consistent pressure against the crankshaft and resisting oil seepage. The included new gasket and installation hardware reduce gaps and provide a more reliable mating surface compared with reusing old components.

• Die-cast aluminum cover resists warping and improves sealing surface integrity.
• Updated seal design optimizes lip contact and reduces oil migration.
• New gasket and hardware ensure proper torque and alignment during installation.

What comes in the box and what should I prepare for installation?

The package includes the rear main seal cover, the updated seal, a replacement gasket and the necessary installation hardware. Installation requires moderate mechanical skill and basic tools; removal of the transmission or access via a service pit may be necessary depending on vehicle layout.

• Included: aluminum cover, pre-set seal, replacement gasket, bolts and fasteners.
• Tools: socket set, torque wrench, seal installer or suitable driver, gasket scraper and cleaning solvent.
• Time & labor: plan for several hours; professional installation recommended if you lack transmission removal experience.

Does this kit replace specific OEM part numbers and how do I confirm fit?

This RADHLBNIU kit is intended to replace OEM numbers 635-518, 12633579 and 12639250. Always compare the part number on your existing cover or consult the vehicle’s service documentation to confirm a match before purchase.

• Replaces: 635-518, 12633579, 12639250.
• Verify: check current part number on vehicle or compare physical measurements and mounting pattern.
• Contact support: provide VIN and engine size if you need help confirming compatibility.

Who is this for: This rear main seal kit is intended for owners, fleet managers and independent mechanics who service GM full-size trucks, SUVs and vans built with the specified V8 engines and model years. It’s suitable for anyone replacing a leaky or worn rear main seal who wants a durable die-cast aluminum cover, a modernized seal design and a full installation kit to restore a reliable crankshaft-to-block seal.