The transmission in JK's run hot stock, when you add larger tires and weight it works harder and gets hotter. The factory trans cooler just doesn't cut it, its riddled with flaws. Our unit works, it keeps the basics in mind. disipate heat...period! Copper is the best material for conducting the heat out of the fluid while aluminum is ideal for transferring and dissipating that heat Protected from possible damage during installation by plastic fin guards and powder coat finish.