I have a 1996 hitachi EX300LC-3C and I have oil dripping out of the hydraulic transmission dip stick and the oil fill port. It was not doing this when I parked it in December. When I remove the dipstick it oozes oil out of it and it is coming out of the fill port.
Pump shaft seals are leaking. Not too bad of a job to do. I change all three pump seals and also change the splitter box seal when Im there. Make sure to clean your splitter breather too.
Good Day mr.kdk Often we have found that the root cause of shaft seal failure is that the case drain filters are blocked or the pump bearings have to much movement. Kind regards Uffex 
I don't remember there being case drain filters on a 300. Don't they start on the 400 and larger?
had the same problem with zx 170 pump resealed two or three times still leaked . stripped pumps and found bearing were turning on the casing ,dealership gave us new casing was all right after that hope this helps
Good day Deertracks Yes you are correct my error thank you for your observation and comment. K.R. Uffex