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My three point would not stay up with the engine stopped. It is possible this problem has been there from the factory.

I assumed a bad piston seal of valve on the rockshaft cylinder. During disassembly I noticed that the washer and shims in the relief valve were below the valve spool shoulder while the assembly drawing shows them to be between a shoulder of the valve spool and the spring.

I would assume the assembly drawing to be correct as the shims would be used to adjust the spring tension and therefore the relief pressure. With the shims under the shoulder I think they probably would not allow the valve spool to seat and completely close.

My reason for posting this is that I'm sure this is the first time the rockshaft housing has been opened since the factory. I figure if one was assembled wrong, there were probably many. Anyone seen this before? Was there a known problem.

Just wanting to check my sanity.
 

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If rockshaft piston seals are good then 3 pt leak down could be caused by faulty relief valve,faulty control valve seals which is common cause,control valves clearance set to tight or faulty piston housing. From viewing 2555 parts catalog it appears there were 2 different relief valves(keys 8 or 31) but parts description states both part # subs to same part #s. JD is very proud of their relief valve(AL61753 $350) I agree shim washers should be on top of relief valve stem.

Have you considered to pressure test rockshaft assembly with air?
 

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