There's no greater enemy for a transmission than heat. Whether your 2001 - 2003 ChevyGMC 6.6L Duramax is a dedicated tow vehicle, hardworking fleet truck, or a daily driver with a liking for the drag - strip, you need to ensure that your transmission runs cool. Luckily, Mishimoto has developed a direct - fit transmission cooler to do just that. Our 2001 - 2003 ChevyGMC 6.6L Duramax transmission cooler utilizes a stacked - plate design for maximum durability and powerful cooling. Aside from It's durable construction, this transmission cooler is significantly larger than the stock core. The Mishimoto transmission cooler boasts a 174 - percent greater core volume, and 192 - percent greater fin surface area than the stock 2001 - 2003 Duramax transmission cooler. The included CNC - machined adapters connect directly to the stock transmission cooler lines for leak - free cooling. Direct - fit brackets and tailor - made hoses make installation easy. Like all Mishimoto products, this transmission cooler is backed up by our Lifetime Warranty with Accident Protection for worry free cooling as long as you own it.