Find the Direct-Fit Transmission Coolers & Lines you need to keep the transmission cool in your 2011-2016 Chevy/GMC 6.6L LML Duramax. There are performance thermal bypass valves for some transmission coolers that can take the place of the troublesome factory thermal bypass valve. The increase in fluid capacity and core volume will offer enhanced cooling efficiency with an aftermarket transmission cooler. The cooler lines are available in factory replacement or performance durable braided hoses with billet -AN fittings. Mishimoto, Dorman, BD-Power, and more top-notch manufacturers are available.