This is a damn interesting discussion, I am going to have to do a little experiment, don't know when, I'll have to put a note up on the wall in the garage to remind me so I don't forget when I get a chance to do something to test this. I too have always been told about painting anything that you want the most heat dissipation you can get, paint it black, flat black. This goes for transmissions as well as radiators, "there is a reason they paint them black" was the answer when asked years ago. Polishing the trans body retains heat because it isn't porous anymore, this makes sense. So a "porous" black paint made sense to dissipate heat. But this thread has gave me a serious "hmmmmmmm moment.