I did not have to with the tranny cooler, but I wanted more efficient cooling. One thing that happens with a V shaped motor in an XJ is there is little or no air flow through there. Got it real hot right away with a hood on. So I started looking at every alternative I could to reduce the chance of it ever getting hot again and having to replace head gaskets. The venting, super strong fans and separate oil coolers is what I did. Glad I did. Great trail rig now and it handles hard core stuff just as well without heat problems. I rock crawl with the air running