I've got an auto in my 02 Corolla; up untill now I've always had manual trannies. I LOVE THE AUTO. Anyways, I read here all the time that downshifting an auto is a no-no. Well, in Colorado, it's kind of unavoidable, especially in the mountains; unless you like losing your brakes and scraping yourself off the bottom of a ravine. Is it really that bad to downshift an auto manually? Seems like it's no different than slamming the gas and having it downshift automatically. My Corolla has an overdrive on/off botton on the shifter and I've been using that frequently to help slow down and maintain speed while descending hills. Am I slowly killing the tranny by doing this?