{"product_id":"merc-492","title":"Mercury MerCruiser Rear Crankshaft Oil Seal 26-75980 | GM 454 7.4L Reverse Rotation","description":"\u003ch2\u003eMercury MerCruiser Rear Crankshaft Oil Seal — Part 26-75980\u003c\/h2\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e 26-75980 (also referenced as 75980, 75980T, 26-75980T)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Mercury \/ MerCruiser (OEM reference)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOfficial Product Type:\u003c\/strong\u003e Gaskets \u0026amp; Seals — Internal Engine\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSystem:\u003c\/strong\u003e Crankshaft Sealing \/ Rear Main\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Rear crankshaft \/ rear bearing-cap oil seal, \u003cstrong\u003eright-hand \/ reverse-rotation engines only\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eQty Required:\u003c\/strong\u003e 1 per engine\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Availability:\u003c\/strong\u003e Original Mercury 26-75980 is currently listed as \u003cstrong\u003eno longer available (NLA)\u003c\/strong\u003e from Mercury. Aftermarket replacements are available for these applications.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhat It Does\u003c\/h2\u003e\n\u003cp\u003eThis rear crankshaft oil seal fits the bearing-cap area at the back of the engine, preventing oil from escaping between the crankshaft and the rear main bearing-cap. \u003cstrong\u003e26-75980 is specifically for right-hand \/ reverse-rotation GM 454 engines\u003c\/strong\u003e — MerCruiser used a different seal for standard left-hand rotation engines of the same displacement. Confirming engine rotation before ordering is essential.\u003c\/p\u003e\n\n\u003ch2\u003eCompatible Applications\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eVerify fitment by engine serial number and confirm reverse\/right-hand rotation before ordering.\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e330 GM 454 V8\u003c\/strong\u003e — 1977–1981 | Serial range: 4623115 through 6083144\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e330 MIE GM 454 V8\u003c\/strong\u003e — 1977–1980 | Serial range: 4623115 through 5889913\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e340 MIE with Borg Warner transmission\u003c\/strong\u003e — 1981–1987 | Serial range: 5889914 through 0B788365\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e7.4L MIE with Borg Warner transmission\u003c\/strong\u003e — 1988–1992 | Serial range: 0B788366 through 0D715493\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cem\u003eNot sure it fits? Send us your MerCruiser engine serial number and confirm your engine's rotation direction before ordering.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch2\u003ePart Numbers \u0026amp; Cross-References\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e26-75980\u003c\/strong\u003e — Mercury \/ MerCruiser OEM part number\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e75980\u003c\/strong\u003e — Short-form Mercury reference\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e75980T \/ 26-75980T\u003c\/strong\u003e — Related Mercury-format reference\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFEL17740 \/ Fel-Pro 17740\u003c\/strong\u003e — Aftermarket replacement for reverse-rotation applications\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eBecause the original Mercury part is NLA, aftermarket equivalents are the primary service option for these older reverse-rotation engines.\u003c\/p\u003e\n\n\u003ch2\u003eWhen to Replace\u003c\/h2\u003e\n\u003cp\u003eReplace this seal when:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eEngine oil is leaking from the rear crankshaft area\u003c\/li\u003e\n\u003cli\u003eThe seal is hardened, cracked, or damaged on inspection\u003c\/li\u003e\n\u003cli\u003eLeakage is discovered during flywheel or transmission removal\u003c\/li\u003e\n\u003cli\u003eThe engine is being overhauled or the rear bearing cap is being serviced\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eOil appearing between the engine block and transmission can come from multiple sealing points — diagnose the source carefully before replacing parts.\u003c\/p\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eConfirm engine rotation is \u003cstrong\u003eright-hand \/ reverse\u003c\/strong\u003e before installation — do not substitute the standard-rotation seal\u003c\/li\u003e\n\u003cli\u003eVerify the engine serial number falls within the ranges above\u003c\/li\u003e\n\u003cli\u003eInspect the crankshaft sealing surface for grooves or wear before fitting a new seal\u003c\/li\u003e\n\u003cli\u003eClean the bearing-cap and block sealing surfaces thoroughly\u003c\/li\u003e\n\u003cli\u003eFollow the applicable MerCruiser service procedure for seal orientation and torque specs\u003c\/li\u003e\n\u003cli\u003eMercury parts diagrams list 26-75980 separately from the standard-rotation rear seal — confirm the correct diagram position for your engine before installation\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eParts Desk Insights\u003c\/h2\u003e\n\u003cp\u003eThe most common mistake with this seal is ordering a GM 454 rear main seal without confirming engine rotation. Standard and reverse-rotation 454 engines use different seals, and they are not interchangeable. If you're working on a 330 MIE, 340 MIE, or the reverse-rotation 7.4L MIE, this is the correct seal — but always cross-check your serial number against the ranges above. Because the original Mercury part is discontinued, an aftermarket equivalent such as the Fel-Pro 17740 is the typical service solution for these engines.\u003c\/p\u003e","brand":"MERC","offers":[{"title":"Default Title","offer_id":43563870978084,"sku":"75980","price":75.6,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/e1e0a2d7-f209-4267-bae0-7e9efebc95ae.png?v=1789507756","url":"https:\/\/marisolmarine.com\/products\/merc-492","provider":"Marisol Marine Company","version":"1.0","type":"link"}