I added one last year to my 05' GTP and the temps went from the 220-230 range down to about 170-190 by the time I get home. The transmission coolers in these radiators do suck. I also had an undersized radiator as well it was 5/8" thick, just installed a 7/8" radiator (was supposed to be 1") and the temps seem to have evened out. The trans cooler is stand alone so I didn't expect it to change. I did have an issue Wednesday. I noticed I needed to go ahead and replace the lines since they were a year old and that's something I always recommend on regular trans hose and clamps. Well going down the street I was on it pretty hard and about the time it was at the top of 2nd all I see is a huge cloud behind me. I coasted the rest of the way to the house and could feel it slipping a little and had trans fluid dropping from all under the bodywork. The back of the car was covered as I discovered when I tried to lift the trunk and my hand slipped into the spoiler. So I cut the line and put new clamps on it until this weekend when I change the hose and look for something better. I lost 7 quarts in that time. So check and change those trans cooler lines even if you are using something better.
Jeff
