Major problem with 318

Well I want to say this is my first post on any tractor forum. I bought my tractor with 600 hours from a coworker. The only thing wrong with it was the paint was starting to chip since it was left outside in the cold Maine winters. I have done a dramatic restoration, paint job,degreased frame, new tires, controls, etc.

Right now I'm having a hard time trying to diagnose what the problem is now. This winter I was very low on hydro fluid, I read somewhere that I could add trans fluid dexron 3 to he hydro fluid. I added it and it seemed to be fine and then I noticed the reverse speed was slower. Not sure if this was related to he difference in fluid.

Second issue is that when I move the throttle forward or reverse there is a jerking motion that is quite severe. I checked the linkage and I didn't seem to notice anything out of the norm. But I'm not quite sure what to look at.

Third issue is that when the tractor is off I can just roll it around. Is this a normal thing. for some reason I thought it should not move at all. What could cause this to happen.

Thank you for all the help. I'm trying to keep this tractor in tip top shape