Hi my name is XXXXX XXXXX I can answer you question.
is not recomended to do that as the transmission does it on its own. it is programed to do it. however. in an emergensy; say your brakes go out andyou need to slow down you can graduately down shift the transmission one gear at the time
Why not recommended?
what will hapen if you do it too ofthen is that the hard parts inside your transmission will star to take extra stress and will were out sooner.
the hard parts of your transmission are like planetaryes, imput shaft, output shaft, ring gears, drums,etc. this parts are very expensive and when a transmission goes out ths parts are the ones that make the price higher.
when the transmission downshifts automaticly is giving time to evryting insidethe trans to slow down and cause the least amount of estress posible and prolong the life of you transmission.
I hope I give you what you were looking for and if there is anything else Ican do for you let me know.