linny

Hey guys, well yesterday I had to completely replace the radiator on my ZJ because the other one had completely rotted out from the bottom (go figure), and after I replaced it my friend noticed that it the radiator was leaking ATF fluid from the top line going into the radiator. It's not the actual coolant line, it's the small one that screws on with a flange nut. I tightened it and it stopped, but the question I had was I thought the transmission cooler sat in front of the heater core in the grill, why would the ATF have a line that ran into the radiator. I've only started fixing various things this 96, and am just curious.

JJCIII

Most vehicle transmission fluid is cooled in the radiator. The smaller one you see in most cases is just an extra cooler

dave1123

This is correct. The main transmission cooler is in the radiator. The aux cooler in front of the rad is basicaly for additional cooling with the tow package. What most people don't realize is the rad cooler also WARMS the trans when it's cold. My brother had a leaky rad cooler so he bypassed it. Worked fine until winter. He started having shifting problems when the trans was cold and it took a lot longer to warm up.