JD3720 hydraulic lift arms not lifting

[jdauto3720]

hello, recently purchased a 08 JD 3720 tractor, i believe the 3 point hitch and pto was rarely ever used.(used for plowing snow). i pushed the rockshaft lever forward to drop the arms, they did drop but will not lift back up. all other hydraulics work fine. checked the fluid and it appears to be low on the stick, fluid appears to be milky, so i drained it. lever was stiff but all linkages are moving. the rate of drop adjustment knob was stuck but was able to un-seize and doesn't make a difference.
Wondered if anyone had any advice or maybe somethings i could try on my own before hauling to a dealer as they are very far away. Im pretty mechanically inclined but typically with cars, this is my first tractor.
thanks in advance for any help! i appreciate it.
john

 

[Kyle_in_Tex]

There are linkages that go under the seat to a box on the other side. I've had to tear into mine just to free up a rusty shaft. It was a pain, because I had to make do a few home made punches to drive the shaft out of the rust.
Search 4310 rockshaft in Google.

 

[jdauto3720]

yes, i think i know the linkages you are talking about. i removed the wheels/tires so i was able to see everything below the seat. mine all appear to be moving ok, I've traced right from the lever through a series of linkages/cables. until it enters the case assembly. I'm staring to think maybe the control valve or something is stuck open/closed. but ill give that ''4310 rockshaft'' a search and see what comes up.
thanks for the info!