Duramax 5/8" Transmission Cooler Line Kit with Fluidyne Transmission Cooler for 2001-2016 Chevy Silverado & GMC Sierra

Before Ordering: Select the Correct Kit for Your Truck Use the reference photos below to identify your factory transmission cooler line configuration and select the matching kit option. Not sure which kit you need? Send us your VIN or photos and we'll help verify fitment before you order. Stop Leaking Duramax Transmission Cooler Lines for Good Tired of leaking Duramax transmission cooler lines? Our upgraded 5/8" transmission cooler line kit replaces failure-prone factory lines on 2001-2016 Chevy Silverado and GMC Sierra Duramax trucks. Built to last and backed by our No Questions Asked Lifetime Warranty. Leaking transmission cooler lines are one of the most common issues on Duramax trucks. Factory lines can corrode, seep, or fail over time, leading to transmission fluid loss and potentially expensive repairs. Our upgraded 5/8" Duramax Transmission Cooler Line Kit is designed to provide a reliable, long-lasting solution for Chevy Silverado and GMC Sierra HD trucks equipped with the Duramax diesel and Allison transmission. Whether you're fixing an active leak or replacing aging factory lines before they fail, this kit delivers the durability and performance your truck needs. Features ✔ Replaces failure-prone factory transmission cooler lines ✔ Fits 2001-2016 Chevy Silverado and GMC Sierra Duramax diesel trucks ✔ Designed for Allison 1000 transmissions ✔ High-quality fittings and components ✔ Helps prevent transmission fluid leaks ✔ Designed for long-term reliability ✔ Easy installation Fits • LB7 Duramax (2001-2004) • LLY Duramax (2004.5-2005) • LBZ Duramax (2006-2007) • LMM Duramax (2007.5-2010) • LML Duramax (2011-2016) Vehicle Applications • Chevy Silverado 2500HD & 3500HD • GMC Sierra 2500HD & 3500HD Don't wait until a small leak becomes a costly transmission repair. Upgrade your Duramax transmission cooler lines today and drive with confidence. No Questions Asked Lifetime Warranty We stand behind every kit we sell. If you ever experience an issue, we'll make it right. Why Upgrade Your Duramax Transmission Cooler? If you tow heavy trailers, haul loads, or drive in hot climates, excessive transmission temperatures can shorten the life of your Allison transmission. The Fluidyne Heavy Duty Transmission Cooler provides over four times the cooling efficiency of the factory cooler and can reduce transmission temperatures by up to 20°F. Whether you're towing, daily driving, or running performance upgrades, improved cooling helps protect your transmission and maintain consistent performance. Excessive heat is one of the most significant factors that can reduce the longevity of your transmission. Over time, high temperatures can lead to premature wear, decreased performance, and costly repairs. Unfortunately, OEM transmission coolers often fall short when it comes to efficient heat dissipation, especially under heavy loads or in high-performance applications. To protect your transmission and extend its lifespan, upgrading your cooling system is essential. Introducing the Fluidyne High Performance Bar and Plate Transmission Fluid Cooler, available for 2001-2016 GM 6.6L Duramax applications. Each package includes the correct Fluidyne transmission cooler and Duramax 5/8" Transmission Cooler Line Kit for your selected year range and engine combination. Designed with the densest fins per inch available on the market, the Fluidyne cooler provides unmatched cooling performance. Its fully welded internal splitter plates prevent fluid contamination between hot and cold sides, ensuring the purity and effectiveness of your transmission fluid. Constructed from aerospace-grade aluminum using bar and plate technology, this cooler maximizes heat exchange while minimizing pressure drop, offering a perfect balance of efficiency and durability. This cooler is a direct replacement for your factory unit, utilizing existing factory mounts for an easy, hassle-free installation. Finished with a proprietary powder-coated heat-wicking compound, it further enhances heat transfer efficiency. Backed by a limited lifetime warranty, the Fluidyne cooler is engineered to deliver long-term reliability and help keep your Allison transmission operating at cooler, safer temperatures. Key Features: Over four times the heat dissipation capacity compared to stock coolers Direct bolt-in replacement for easy installation Maximum fin density for superior cooling Fully welded internal splitter plates to prevent fluid contamination Pressure tested up to 250 PSI to ensure leak-free performance and long-term reliability. Aerospace-grade aluminum with bar and plate construction for optimal durability Proprietary fin design for enhanced thermal performance Powder-coated with a specialized heat-wicking compound Limited lifetime warranty for peace of mind Vehicle Fitment ✔ 2001-2016 Duramax ✔ Chevy Silverado 2500HD & 3500HD ✔ GMC Sierra 2500HD & 3500HD Not sure if this cooler fits your truck? Send us your VIN and we'll verify fitment before you order. What's Included ✔ Duramax 5/8" Transmission Cooler Line Kit ✔ Fluidyne Heavy Duty Transmission Cooler ✔ Required fittings and adapters ✔ Model-specific components based on your selected year range ✔ No Questions Asked Lifetime Warranty FAQ Q: Will this transmission cooler line kit fit my truck? A: This kit fits select 2001-2016 Chevy Silverado and GMC Sierra HD trucks equipped with a Duramax diesel engine and Allison 1000 transmission. Use the fitment guide and reference photos above to select the correct kit. If you're unsure, send us your VIN and we'll verify fitment before you order. Q: What are the signs of a leaking Duramax transmission cooler line? A: Common symptoms include transmission fluid spots under the truck, wet or oily cooler lines, low transmission fluid levels, transmission overheating, and visible leaks around factory crimp connections. Q: Why do factory Duramax transmission cooler lines fail? A. Factory transmission cooler lines commonly fail due to corrosion, deteriorating crimp connections, age, and exposure to heat and road debris. These issues can lead to transmission fluid leaks and costly repairs. Q: Does this kit work with Allison 1000 transmissions? A. Yes. This kit is designed for Duramax trucks equipped with the Allison 1000 transmission. Q: Is this kit covered by a warranty? A: Yes. Our Duramax 5/8" Transmission Cooler Line Kits and Fluidyne Coolers are backed by our No Questions Asked Lifetime Warranty. Q: Will this kit help stop transmission fluid leaks? A: If your leak is coming from the factory transmission cooler lines, fittings, or crimp connections, this kit is designed to eliminate those common failure points and provide a long-lasting solution.