There is a main control spool beside ladder, beside header height control valves that may have lost their o-ring. When oil gets hotter it is thinner and lets more by until you have no pressure left. Happened to me once that way. Header wouldnt lift, but dont know about unloading auger, never tryed it then because it didnt work. Also had to put a different valve body on header height control because of an internal crack that you can hear the head creeping down with everything shut off and real quiet like especially at night. There is another control spool also in this line under the floor which controls the rate of drop which also may have left go. Hope this helps. -dude-