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Hi Rick,had the same problem awhile back.I searched the archive's for llamas fine explanation of how it all came apart and goes back together.Oh and llamas if by chance you happen by and read this, Thank you again. Your friend,Jay 2NSC What's likely happened is that the pump control valve has come unhooked from the touch control lever linkage and is stopped in the "lift" position. The pump is controlled from the suction side, and the inlet valve is the "on-off" switch for the pump. Due to the valve design, if the inlet valve is open (pump pumping and raising the lift) the exhaust valve must be closed (lift cannot lower). It sounds as though the control valve is stuck in the "lift" condition, the hitch is all the way up against its mechanical stop, and the noise you hear is the pump making full pressure against a lift that won't move, and blowing off the pressure relief valve. Normally, the control linkage prevents this condition by putting the valve into neutral when the lift reaches the top of its travel, but that won't happen if the valve has come unhooked from the linakge. You'll need to drain the oil, remove the inspection covers, and exmaine the connection between the linkage and the valve spool. The linkage comes down from above in the form of two vertical steel arms with holes in the ends. These holes hook over a T-piece connected to the rear end of the valve spool, and they stay connected by the spring pressure of the arms only. If it's disconnected, you can hook it back up through the inspection cover holes and the drain plug hole - but it's fiddly work and you'll likely have to try 23 times before you get it to pop back together. I've seen this happen multiple times on a 9N/2N while grading or blading a rough road, especially if the touch control lever is out of adjustment or the friction damper is not working. I theorize that the shocks from the blade are transmitted back into the control linkage via the draft control spring and link, and if the linakge is somehwat free to move and vibrate, the ends of the control arms jump off the valve spool connecting T. I have secured more that one of these by wiring the control arms to the T. If that's what it is, hook it back up and it will work normally again. Replace and adjust the friction disk as soon as you can, it damps the touch lever linkage and prevents lost motion in the control arm linkage. Be careful when remving the pressure plate, it's cast aluminum and it breaks easily. If that's not is, post back with what you find. HTH llater, llamas
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