Quantity In Stock: 5+
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 Duramax diesel trucks
✔ Compatible with Allison 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.
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 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.
Q: What is included with the kit?
A: Each kit includes the components necessary to replace your factory transmission cooler lines. Components vary based on the selected year range and transmission cooler line configuration.
No Questions Asked Lifetime Warranty
We stand behind every kit we sell. If you ever experience an issue, we'll make it right.