When you turn the wheel(input) the wheels should turn instantly(output). Just follow the mechanical path from the wheel to the steering knuckles. Have someone turn the steering wheel while you watch what happens. Watch the steering shaft, is there immediate response at the end where it goes into the box when the wheel is turned? Watch the input and output shafts on the steering box, is there instant response from the output shaft when the input is turned? Watch the steering linkage and make sure it is tight and responsive.
The joints on the steering shaft will wear and produce sloppy steering. The box can wear and produce sloppy steering, and the linkage ends can wear and produce slop. You need to isolate it to one or more components. If it's the box, there should be an adjustment screw located on it that lets you tighten the gear mesh back up as it wears.