Originally Posted by abushong504

I think I may know your problem. I was having the exact same issue. Upon installing the turbos in my car I purchased a Koyo racing radiator. It was for a manual transmission car. I got it installed and just used the tranny cooler to cool the fluid.

My car would go into limp mode after getting on it pretty hard and I could never figure out what it was. I finally got my tranny temp gauge installed and one day I was sitting in traffic for a very long time on a hot day and the temp gauge got near 300 degrees. My car then went into limp mode. I figured out, the temperature was getting too hot which would cause the limp mode problem.

After researching for a better cooler I figured out this issue: when I got rid of the stock radiator, I got rid of one part of the tranny cooler system. The stock tranny lines are fed through the stock radiator which is how it is cooled normally. So when you get rid of that cooling effect, you are just trying to cool the tranny fluid with that tiny cooler.

Your lines should be ran from your tranny, to your radiator, to your tranny cooler, and then back to your tranny.

This will allow a lot better cooling during stop and go traffic, as the fans will kick on and help cool and also while driving.

My car has yet to go into limp mode sense, and the temp gauge is always in a good range.

I would recommend buying a different radiator that is made for a automatic car and run your lines that way. It will definitely be a lot cheaper than buying a built tranny.

Hope this helps