Mishimoto 2019+ RAM 6.7L Cummins Thermal BypassThe transmission is the backbone of your RAM. Its responsible for transmitting large amounts of torque from your 6. 7L Cummins powerplant, and that torque generates heat. If that heat isnt dissipated, it can destroy your transmission. The transmission cooler does a good job of keeping trans fluid temperatures in check, but only if the fluid can reach it. The stock cooling system of both the 68 RFE and Aisin AS69RC utilize an in line thermal bypass