I have a 2012 mazda 3 hatch with the 2.5L in it, 5-speed automatic. I live in Texas so its usually pretty hot. I was told to change my transmission fluid now (just hit 50k, the manual says nothing about when to change) and to the change it every 30k miles. I was also told I should get an external transmision fluid cooler. I see I can get them for rather cheep. I was wondering the pros and cons of them, and suggestions on which to get for under/around $50?