{"product_id":"moker-ls-rear-main-seal-housing-cover-billet-aluminum-replacement-for-gm-ls1-ls2-ls3-4-8-6-2l-leak-resistant-cnc-machined","title":"Moker LS Rear Main Seal Housing Cover — Billet Aluminum Replacement for GM LS1\/LS2\/LS3 4.8–6.2L, Leak‑Resistant CNC Machined","description":"\u003cp\u003e\u003cstrong\u003eMoker's billet aluminum rear main seal housing is a direct-fit replacement for GM OE covers (12639250, 12633579) that restores a leak-free seal at the crankshaft outlet on LS-series engines.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eIf your LS-based Chevy, GMC or Cadillac is showing oil at the rear of the engine, this one-piece cover from Moker gives you a durable, precisely machined alternative to brittle factory cast housings. Built to work across a broad range of LS platforms, the housing replaces worn or cracked originals and helps prevent future leaks that can foul the flywheel, clutch, or surrounding components.\u003c\/p\u003e\n\n\u003ch3\u003eWill this housing fit my LS engine and which OE numbers does it replace?\u003c\/h3\u003e\n\u003cp\u003eThis Moker rear main seal housing fits most production LS blocks including LS1, LS2, LS3, LS6, LS7 and common truck variants (LM7, LQ4, LQ9). It replaces GM OE part numbers 12639250, 12633579 and aftermarket code 635-518.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCompatible with 4.8L, 5.3L, 5.7L, 6.0L and 6.2L LS engines.\u003c\/li\u003e\n  \u003cli\u003eDirect-fit for production LS engine blocks—no block modification required.\u003c\/li\u003e\n  \u003cli\u003eReplaces listed GM OE numbers for straightforward purchasing and fitment.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow does the billet construction help prevent leaks compared to the factory part?\u003c\/h3\u003e\n\u003cp\u003eMoker machines the housing from high-strength billet aluminum, which resists cracking and distortion that can occur with cast housings under heat and torque cycling. The result is a firmer mounting surface for the seal and a reduced chance of gap formation that leads to oil seepage.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eBillet aluminum provides improved rigidity and corrosion resistance.\u003c\/li\u003e\n  \u003cli\u003eCNC machining ensures flat sealing faces and consistent bolt-hole alignment.\u003c\/li\u003e\n  \u003cli\u003ePressure-tested tolerances minimize sealing failure under load.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eIs this suitable for performance builds or just repairs?\u003c\/h3\u003e\n\u003cp\u003eIt works well for both: as a replacement for damaged OEM covers and as an upgraded component in high-stress or performance engine builds. The stronger material and precise fitment give added reliability where higher revs and track use demand better durability.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eIdeal for street, towing, and light performance applications.\u003c\/li\u003e\n  \u003cli\u003eOne-piece design fits standard LS block geometry for easy installation.\u003c\/li\u003e\n  \u003cli\u003eRecommended when rebuilding an engine or replacing a leaking cover.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho this is for: Mechanics, DIY enthusiasts, and engine builders working on GM LS-series platforms who need a dependable rear main seal housing that outlasts the OEM cast part. If you’re replacing a leaking or cracked rear cover on Silverado, Sierra, Tahoe, Yukon, Escalade, Avalanche or similar models, or assembling a fresh LS engine and want a stronger, precisely machined housing, this Moker product is designed for your build.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Does this replace GM part 12639250 and 12633579?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes. The Moker housing directly replaces GM OE numbers 12639250 and 12633579 for LS-series engines.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Can I use this on LS truck engines like LQ4\/LQ9?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes. It fits common truck LS variants including LM7, LQ4 and LQ9 without block modification.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"Moker","offers":[{"title":"Default Title","offer_id":67587443294393,"sku":"B0FNCP5ZTC","price":104.68,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0822\/3765\/3177\/files\/moker-front-overview-housing.jpg?v=1790508288","url":"https:\/\/redleafauto.ca\/products\/moker-ls-rear-main-seal-housing-cover-billet-aluminum-replacement-for-gm-ls1-ls2-ls3-4-8-6-2l-leak-resistant-cnc-machined","provider":"Redleaf Auto","version":"1.0","type":"link"}