hi tomason2 from what you are describing i would check the inching pedal lever has not slipped around on the shaft so loosen the the lever cap screw and make sure the shaft is all the way back clockwise and then put lpedal lever back on and tighten cap bolt i suspect the lever has slipped forward on the shaft and when you depress inching pedal the reason it still drives is that you are not getting full opening of the valve see how you go
hi richard