{"product_id":"penn-grade1-classic-gl-4-gear-oil-sae-80w-90-4-1-qt-mineral-formula-for-soft-metal-synchronizers","title":"PENN GRADE1 Classic GL-4 Gear Oil SAE 80W-90 — 4×1 qt, Mineral Formula for Soft-Metal Synchronizers","description":"\u003cp\u003e\u003cstrong\u003ePENN GRADE1 Classic Multi-Purpose GL-4 Gear Oil SAE 80W-90 is a mineral-based lubricant formulated for classic manual transmissions and transaxles that use yellow metallurgy.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThis four-quart pack of GL-4 80W-90 gear oil is blended from premium mineral base stocks and tailored additives to protect synchronizers, bushings, thrust washers and other components commonly found in older manual gearboxes. It avoids modern friction modifiers so it doesn't disrupt synchronizer engagement, and it's not an API GL-5 extreme-pressure product—so it's ideal only where GL-4 performance is specified or where soft-metal compatibility matters.\u003c\/p\u003e\n\n\u003ch3\u003eWill this oil protect synchronizers and brass\/bronze components?\u003c\/h3\u003e\n\n\u003cp\u003eYes. The formulation is deliberately compatible with yellow metallurgy—brass, bronze and copper—used in synchronizers and related parts. It reduces wear and helps maintain smooth shifts without the negative effects some friction additives produce.\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eFormulated for soft-metal compatibility in synchronizers and bushings\u003c\/li\u003e\n  \u003cli\u003eFree of friction modifiers that can impair synchronizer action\u003c\/li\u003e\n  \u003cli\u003eMineral base stocks chosen for stable film strength at operating temperatures\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eIs this gear oil suitable for limited-slip or GL-5 rated applications?\u003c\/h3\u003e\n\n\u003cp\u003eNo. This GL-4 product is not intended for limited-slip differentials or applications requiring API GL-5 extreme-pressure protection. Using it where GL-5 or specific OEM fluids are required could under-protect gears under very high-pressure conditions.\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eNot formulated with EP additives typically found in GL-5 oils\u003c\/li\u003e\n  \u003cli\u003eAvoid in limited-slip units that require special friction characteristics\u003c\/li\u003e\n  \u003cli\u003eCheck vehicle manual; use only when GL-4 is specified\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow much product do I get and how is it packaged?\u003c\/h3\u003e\n\n\u003cp\u003eEach purchase contains four 1-quart bottles—convenient for a full service or multiple fill-ups. Quart bottles are easy to store in a garage or bring to a shop, and the multi-pack helps ensure you have the correct fluid on hand for classic vehicles.\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eQuantity: 4 × 1 quart bottles per pack\u003c\/li\u003e\n  \u003cli\u003ePackaging suited for storage and garage use\u003c\/li\u003e\n  \u003cli\u003eBring to service appointments or keep as a spare supply\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat vehicles and situations is this brand best used for?\u003c\/h3\u003e\n\n\u003cp\u003ePENN GRADE1 80W-90 GL-4 is targeted at older cars, trucks and motorcycles with manual transmissions or transaxles that specify GL-4 and use soft-metal components. It’s also useful for restorations and maintenance of vintage gearboxes where preserving original materials and shift feel is important.\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eClassic and vintage manual transmissions that call for GL-4\u003c\/li\u003e\n  \u003cli\u003eRestoration projects where original metallurgy must be preserved\u003c\/li\u003e\n  \u003cli\u003eOwners seeking a mineral-based option without friction modifiers\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho this is for: Mechanics, restorers and owners of classic vehicles who need a reliable GL-4 80W-90 gear oil that respects yellow metallurgy and synchronizer performance. If your vehicle manufacturer specifies GL-4 (not GL-5) or you maintain older transmissions with brass\/bronze parts, this PENN GRADE1 four-quart pack gives a practical, correctly formulated choice for routine service and preservation.\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: Can I use this in a transmission that calls for GL-5?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: No. This is a GL-4 formulation and lacks the extreme-pressure additives in GL-5 oils; follow your vehicle’s specification.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Is this suitable for limited-slip differentials?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: No. It does not contain limited-slip friction modifiers and is not intended for limited-slip applications.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"PENN GRADE1","offers":[{"title":"Default Title","offer_id":67586931982521,"sku":"B0CHG3X79B","price":117.2,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0822\/3765\/3177\/files\/penn-grade1-front-label-80w90-quart.jpg?v=1790497239","url":"https:\/\/redleafauto.ca\/products\/penn-grade1-classic-gl-4-gear-oil-sae-80w-90-4-1-qt-mineral-formula-for-soft-metal-synchronizers","provider":"Redleaf Auto","version":"1.0","type":"link"}