I am a new tractor owner and have purchased a Yanmar1510D. I still need to purchase a manual but do have one that is specific to a Yanmar226. My question is the transmission fill - I am unable to locate a dipstick and it is my understanding that the system uses the same oil for the transmission and hydraulic system. There is a fill behind the seat but no dipstick. Could this be the fill for the system and if so how much do I fill it without overfilling the system. Any help would be great - Thanks.