transmission shifting problems?

the transmission is not shifting properly.. either goes up to 4000 revolutions to start shifting or i do it manually by reducing the gas pedal.. when it goes up the hill, right now doesn't go more than 45 miles per hr..

I'd need to drive this, but I'm wondering if the engine is losing power and you are just on the throttle hard enough that the transmission is responding as if you are dragging a heavy load. Throttle position can dictate shift points. The fact that you can make it shift has me leaning towards inputs or overall torque.