I correct myself the machine creeps in forward.
Just bought a 65B, probably '80's model. Used/abused by non-operators, poor/no maintenance, sat for probably 15+ years. Some thing happened with mine, put it in 1st gear, low range, toggled the reverser and barely got a twitch out of the wheels. Kept switching between forward and reverse and finally got it to drive for a couple seconds before losing power/speed and it stopped and rolled down the grade as though out of gear. Quickly toggled the reverser to neutral than back to drive and it took of at full power again for a second or two. It seemed to get a little better the more I ran it but am told the tube with no cover to the left of driver's seat is the transmission fill/dip stick tube. (It's missing the dip stick) I suspect it's low on trans. fluid and want to empty and flush the trans before putting machine to work in the spring, not going to run it any more until I get it cleaned out.
The hydraulic reservoir in the rear is full, no reason it shouldn't run except that the person who told me it has a separate reservoir for trans fluid is correct.
Did you get your machine to run properly?