false, the fluid degrades over time. When changing ATF fluid be sure to wear safety glasses and rubber gloves. ATF fluid from any of the reading I have done on it is actually not healthy to be exposed to direcly. Just like being exposed to motor oil direclty (on skin, in cuts etc.) is not healthy.
You do not only want to change your fluid by dropping the pan, but instead you want to have the transmission flushed. The flushing gets more of the fluid out of the transmission. Be sure to have your transmission filter changed as well, there is all the contaminents in that along with any fine metal particles from the original brake in period of your transmission.
Change your fluid reguarly, and you will have a transmission that works properly for a long time!
2005 Ford Ranger SuperCab XLT 4x4
4.0L V6. 4:10 Gears. BFGoodrich Mud Terrain T/A KM's, Torsion Bar Crank, Bilstein HD Shocks, Autolite Platnium 5143 Plugs, Autolite Professional Wires, Tonneau Cover, Bed Liner, Chrome painted rear differental cover... Thats it.