Our Heavy Duty Oils & Fluids section brings together reviews, comparisons and practical buying guides to help you find the right products for your vehicle, whatever your budget.
How we researched this guide We compared five NLGI #2 greases across three thickener families — calcium sulfonate, lithium complex and polyurea — against maker documents: Lucas data sheets and its formula-change page, Valvoline technical bulletins, and ExxonMobil product data for the two Mobil greases. Every test figure here (weld point, wear scar, Timken load,
How we researched this guide We compared six degreasers across three families — alkaline concentrates, citrus concentrates and a ready-to-use spray — checking each against maker and listing documents: Oil Eater via its listing data and Grainger record, Zep via its product pages and safety data sheet, Purple Power via its directions and maker FAQ,
How we researched this guide We compared the three heavy-duty diesel engines on maker evidence only: the Stellantis 2025 Ram Heavy Duty overview for the Cummins ratings and transmission, Ford-published Super Duty outputs for both Power Stroke versions, and GM Duramax L5P ratings carried in GM Authority’s comparison tables and a 2026 dealer listing. Warranty
How we researched this guide We compared fourteen oil filter wrench sets and single tools sold for truck work, then ranked five that cover the heavy-duty field honestly: a 3-jaw set, a wide-range jaw wrench, a heavy-duty strap, a pliers set and a cartridge socket set. For every pick we read the maker or retailer
How we researched this guide We started with the official record: the EPA fuel-economy site states that pickups over 8,500 lb GVWR are heavy-duty vehicles fuel-economy regulations do not cover, so they are not tested and carry no official MPG rating. We then checked factor research on the same site, a Cummins economy white paper