Shifting tranny while moving, bad?

I have heard that Ford auto trannies do not like to be shifted (changing "gears" on the gear selector lever) while the vehicle is moving, such as changing from overdrive to drive on a downhill slope to control speed. Has anyone heard this? Is this really as bad as these people say it is? I'm not talkng about running 6000 RPMs down the interstate in second gear, but going downhill at 50mph, your speed increases quickly due to the hill so you change to "regular" drive to keep your speed down without wearing the brakes so much.

I havent heard such a thing; not about Fords or any other car with an automatic tranny. Naturally I dont mean downshifting when the cars downhill speed has reached 80 or higher.
In our 92 Escort I do it whenever we are driving in hilly country. I often leave it in Drive (instead of in Overdrive) when around town. That way it only shifts up to 3rd, not to 4th and into torque converter lockup.

Obviously, somebody in their halfway-right mind wouldn't shift to second going 100 mph, though I'm bad to shift from OD to drive at about 60mph during a decent, and then shifting back to OD once I'm to the bottom of the hill. My dad told me about this rumor, as he tore up the transmission on his service van (a Ford Econoline series van) by doing that within a few thousand miles, but then again, he also had the thing grossly overloaded (carrying way over 10,000 pounds of electrical equipment at all times :screwy:). Not to mention whatever may have been pre-existing before it was given to him. :banghead: