here are questions that i was telling a friend about putting a trans cooler...
what you need to find out then is if it has an internal thermal bypass that keeps the fluid in teh transmission until its warmed up. Some of the dodges have that, and many newer transmission do. Transmission do need to be up to temp too, just like an engine (not teh same temp of course). trans shops (good ones) will tell you not to over cool a transmission
I see why they are adding it, but I don't see why they don't just add an external filter to stop the radiator exchanger buildup. If its already plugged, then you have no choice..
most will probably say the external cooler won't cool it enough, but thats not what I'm worried about.. you can get bigger/better trans coolers to fix that. What I'm worried about is being in a cold area with only an external cooler and no thermal bypass. anyplace that stays below freezing for days on end is where you will find people that know about it..