Every truck owner knows that it doesn't matter how powerful or reliable your engine is if you can't get any power to the wheels. The transmission mated to your 2001 - 2005 LB7LLY Duramax is essential to everything your truck does, and keeping it cool is crucial. Upgrading your transmission cooler with a Mishimoto performance transmission cooler is a good start, but the fluid still needs to get to the cooler. That's where this 2001 - 2005 GM 6.6L Duramax (LB7LLY) Transmission Line Kit comes in. These high performance lines are constructed with a durable PTFE line that's wrapped in a high - strength nylon braid. The PTFE line is extremely oil and heat resistant for durability in even the harshest environments. To protect the lines against higher line pressures that come with performance transmissions, We've wrapped them in braided high - strength nylon. This wrap prevents expansion and further protects the lines from abrasion. Finally, these lines are capped off with - 10AN fittings for a secure and leak - free connection. Like all Mishimoto Duramax products, these transmission lines are backed by our Mishimoto Lifetime Warranty for a lifetime of performance.