3PH wont raise

[arcteryx]

Tractor is a L2600DT. Fluid is good but the 3PH won't raise. I have removed the tranny cover and inspected the control valve. When the valve is removed, I can blow compressed air into one of the ports and it does raise the lift arms while on the bench. But when I do this with the control valve on, it does not.

Also, looking at the parts diagram, I don't have the hydraulic piston and 2 orings in the picture attached. This is from the l2600DT parts book. Should I?

 

[Ken45101]

FWIW, I had an IH2505 and the lift arms would not stay up. I finally took it too an IH dealer, who had it for two months, could not solve the problem and charged me a couple of hundred bucks. They told me they thought the engine block was cracked.

I bought my first Kubota and eventually gave the 2505 to a friend of my son. He found the problem!
An incorrect hydraulic filter!