Shouldn't really have any oil dripping out the tube.....that would make me want to look at the screen where the draft tube sticks in the top of the valve cover. 

Minor blowby is to be expected by 5800 hours.  We used to use front (actually mid) mout cultivators.   The 4010 was probably about 6000 hours when we first started using it, and there was enough stink coming out the draft tube to make you fold the culitivator ahead or shut the engine down when you were going to work on it for more then just a few seconds.  You could work on the one on the 4430 as long as you weren't right at the center row, but later, as it got more hours, it became the same way.  Today at 8888 hours you don't want to be below the level of the tube anywhere in the area of the tractor for more then a minute or so unless there is a strong favorable wind.