Komatsu 85e trans oil problem

I have a komatsu d85e-21 dozer that has developed a trans leak that only leaks when the right side is down in the ditch and then not all the time. It started a week ago Friday, stopped moving, filled with oil, about 5 gallons then went back to running. Worked all last week with no problems, same sloop angle, till late late night, checked fluid last night and was low ,took oil out today and it was just below the full mark,that I understand, needs time to run down. The part I don't get is not leaking all the time on the sloop. When it is working on the flat it will not do the leaking thing. Checked for a vent on the right side but cant see far enough back , just too tight to see. No real good dealers in the area to help me so hopefully someone here has had this happed before or nows where to start looking, still have about ten miles to plow on this job with more lined up after this one. Thanks Dan

Komatsu 85e trans oil problem