Well you got me thinking about this one now. So I looked it up.The botom line off the trans is your presser line and should be hooked to the top of the rad.Because of the flow of the fluid.It sould run down, not be pushed up because it make the pump work harder and makes more heat.And thats not good for the trans or the pump.Now the best way to hook it up would be to go from the botom line on the trans to the top of the rad,from the botom of the rad to the top of you trans cooler the botom of your trans cooler to the top of your trans. That way you have more cooling and less strain on the pump and the trans.Hope this helps.