{"product_id":"hayden-automotive-rapid-cool-universal-add-on-transmission-cooler-9-5-11-plate-and-fin-low-pressure-drop","title":"Hayden Automotive Rapid-Cool Universal Add-On Transmission Cooler 9.5\"×11\" — Plate-and-Fin, Low Pressure Drop","description":"\u003cp\u003e\u003cstrong\u003eHayden Automotive 678 Universal Rapid-Cool is an add-on plate-and-fin transmission cooler kit sized 9.5\" x 11\" that reduces transmission fluid temperature for towing and heavy-load driving — not a direct OE replacement.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThis compact Rapid-Cool kit is designed to be installed alongside your vehicle’s existing cooler to lower transmission fluid heat during heavy duty use. The unit uses a plate-and-fin core with Hayden’s patented internal flow geometry to maximize heat transfer while keeping line pressure loss low. The kit ships with the cooler, hose, and mounting hardware, plus 19 mm (3\/4\") barb fittings for positive hose attachment.\u003c\/p\u003e\n\n\u003ch3\u003eHow does this add-on cooler improve transmission performance under load?\u003c\/h3\u003e\n\u003cp\u003eAdding an auxiliary cooler lowers running fluid temperatures when towing, hauling, or driving in hot conditions, helping fluids resist thermal breakdown and protecting seals and clutches. The plate-and-fin core increases surface area for heat rejection while internal turbulation stirs the fluid for better heat exchange without a big pressure penalty.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003ePlate-and-fin core for efficient heat dissipation\u003c\/li\u003e\n  \u003cli\u003ePatented internal flow path boosts heat transfer\u003c\/li\u003e\n  \u003cli\u003eMinimal pressure drop preserves line pressure and shift quality\u003c\/li\u003e\n  \u003cli\u003e3\/4\" (19 mm) barb fittings ensure secure hose connections\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat vehicles and towing setups are compatible with the Hayden 678?\u003c\/h3\u003e\n\u003cp\u003eThis cooler is sized for light- to medium-duty applications such as pickup trucks, passenger vans, Class C motor homes, and travel trailers up to about 24 feet. It’s intended for systems with GVWRs as described and for towing loads up to approximately 5,000 pounds. Because it is an add-on cooler, it works with many factory transmission cooling circuits rather than replacing OE units.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eSuitable for pick-up trucks and vans\u003c\/li\u003e\n  \u003cli\u003eWorks well on Class C motorhomes and travel trailers to 24'\u003c\/li\u003e\n  \u003cli\u003eAppropriate for GVWRs up to 24,000 lb and towing up to ~5,000 lb\u003c\/li\u003e\n  \u003cli\u003eDesigned as an auxiliary, not direct OE cooler replacement\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow is the Hayden 678 built and what comes in the kit?\u003c\/h3\u003e\n\u003cp\u003eThe Rapid-Cool 678 uses a compact plate-and-fin construction to deliver high surface area in a small footprint. Its patented internal turbulation creates turbulence to improve heat exchange without causing large pressure drops. The package includes the cooler core, hose, and mounting hardware so you have everything needed for an add-on installation.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCompact plate-and-fin cooler core, 9.5\" x 11\" overall size\u003c\/li\u003e\n  \u003cli\u003ePatented internal flow path to increase heat transfer\u003c\/li\u003e\n  \u003cli\u003e19 mm (3\/4\") barb fittings for secure hose attachment\u003c\/li\u003e\n  \u003cli\u003eComplete kit: cooler, hose, and mounting hardware included\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow difficult is it to install and what should I check before buying?\u003c\/h3\u003e\n\u003cp\u003eInstallation is typically straightforward for anyone comfortable with basic vehicle plumbing: mount the cooler in a high airflow area, connect hoses to the transmission cooler lines or remote circuit, and secure fittings. Verify clearance, hose routing, and that your vehicle’s cooling capacity and existing connections match a 3\/4\" barb. Remember this product is not a direct OE cooler replacement; it’s intended as supplemental cooling.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eMount where airflow is not obstructed (front of radiator or A\/C condenser)\u003c\/li\u003e\n  \u003cli\u003eConfirm 19 mm (3\/4\") hose compatibility with your lines\u003c\/li\u003e\n  \u003cli\u003eCheck clearance and protected routing to avoid road debris\u003c\/li\u003e\n  \u003cli\u003eFollow torque and fitting recommendations in the installation guide\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for: The Hayden 678 Rapid-Cool add-on cooler suits drivers who tow or haul regularly and need extra transmission cooling capacity without replacing the factory core. It’s a good fit for owners of pickups, vans, Class C motorhomes, and trailers under 24 feet wanting a compact, efficient cooling upgrade with included hose and mounting hardware. If you require an OEM-form direct replacement, choose a model specifically designed to match your vehicle’s OE cooler.\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: Is the Hayden 678 a direct OE cooler replacement?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: No. The 678 is an add-on auxiliary cooler designed to supplement the factory system, not replace the original equipment cooler.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: What hose size fits this cooler?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Use 3\/4\" (19 mm) hose for the barb fittings included with the Hayden 678 kit.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"Hayden Automotive","offers":[{"title":"Default Title","offer_id":48081033232542,"sku":"B000C3DDKO","price":88.93,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0781\/2041\/9486\/files\/hayden-automotive-678-front-view.jpg?v=1785795085","url":"https:\/\/northtrailauto.ca\/products\/hayden-automotive-rapid-cool-universal-add-on-transmission-cooler-9-5-11-plate-and-fin-low-pressure-drop","provider":"North Trail Auto","version":"1.0","type":"link"}