1999 dodge 1500 with automatic overdrive transmission

well the question I have is I was told that when I pull my thirty-foot travel trailer, That I should take my transmission out of overdrive. is that true? I read an article about towing an rv up hills and down hills that you should use overdrive so thats why i'm asking this question. I was told that if you drove takeing your truck out of overdrive pulling an rv it will put less wear and tear on your transmission. I would appreciate if anyone who knows can give me any advise. when i start my truck and put it in drive my overdrive comes on automaticly.