Heat can kill your Transmission whether pulling heavy loads up long steep grades, or just hauling more than you can handle. Overheated oil can reduce the life of your transmission and leave you broken down in the middle of nowhere. BD's Xtruded Transmission Oil Coolers use the same high efficiency Micro Extruded bar technology that is in their air-to-air Charge Air Coolers, providing 22% more cooling over other designs. The 200 Micro Extruded passages provide a large surface area to transfer heat for external air flow cooling while turbulent oil flow design promotes a more complete cooling.