My 2005 Avalon transmission shifts buttery smooth and has 163k miles on the odometer. A dealer changed the fluid at 122k miles, but the fluid is starting to darken somewhat, so I am thinking about changing the trans fluid myself. I have seen several videos of this procedure. However, in one case the fluid was changed by draining the fluid from the drain plug on the bottom of the transmission pan. And another way, the transmission was drained by disconnecting the oil line at the radiator and then attaching a hose to the outlet and starting the engine therein pumping the fluid into a drain pan until the fluid sputters and then stopping and reconnecting the transmission line and repeating the procedure several times until clear red fluid is seen pumping out of the transmission line before buttoning everything back up. Which is the preferred method and how many times is necessary to you drain and refill the transmission to complete the job and get bright red fluid? Also, is Valvoline Maxlife full synthetic WS compatible a good choice or should I stick with the Toyota WS transmission fluid which I made by Exxon Mobil is my understanding?