What are the signs of a bad transmission control switch on 1997 explorer?

I have a 1997 ford explorer with a 5.0 v8 engine. I took it to a mechanic and he told me that I had problems with the transmission control switch. I have had instances when the car hesitates when going in reverse or in drive. I heard these are the signs of a bad tranny but is the control switch the problem here or is it the transmission? And where is this switch located?|||i think he means the range sensor that is on the side of the trans linkage and will not cause your problem a check engine light would be on for that so if fluid is not low you could try changing it with the filter but if still does it then will need rebuilt the rubber lip seals in the trans are worn