Motor riving up and act like it don't want to change out

Ok so when u get in my car and crank it it does good and first taking off is good but when u get going down the road over 40 mph is when I always notice it but it's like it don't want to change out and u can hear the motor riving up higher and higher the faster u go and the rpm hand gets higher and higher u would think it would change out or something aventually but it don't. So I decided see how it does in over drive so I look and made sure the over drive button was not lit up on the dash then when I push the button of course u can see the over drive lit up but the thing that gets me u should be able to tell when u switching back and forth but u can't can't tell a difference in either one so can it be possible that it get stuck in over drive off? And another reason why I ask is cause when u do let of the gas the car slows down tremendously Mike the motor slowing it down u ain't even got to touch the brakes for real but basically the way a car would act if someone had over drive off.