i have a rear oil leak on my kubota zd18. it's looks like it's coming from the very back of the motor. i don't know very much about motor. it looks like it may be leaking around the rear shaft. there is a gear back there which attaches to a big weight. anyone know what is causing this? rear main seal possibly??? is this east to get at and fix?? i was doing some very heavy rough cutting today do you think this is why it failed(started leaking?? it's not leaking very badly. i noticed a very small puddle in the trailer.