The factory cooler just sucks. Its not a temperature thing its the leaking. I'm on number two and it leaking again right around where the hoses enter the cooler. I'm thinking it maybe a vibration problem but who knows. All I want to do is cut those sorry a$$ metal lines and put in hoses with clamps. Is there an aftermarket cooler at a reasonable price out there that won't screw up the tranny. Allison said everything had to be right on.