I have a JD 735 that was used. It has a 60 inch deck on the front, and I am now having problems with the hydro drive. There is a dip stick under the seat, and when I experienced the mower slowing down and billowing a lot of smoke out the exhaust, and the blades slowed down, I checked that dip stick. I found that there was very little liquid on the end of the stick. My question is: Does this mower take Hydro fluid or engine oil in the transmission? I do not have a service manual, hence the reason for the question.