1620 hydro prpblem

[cromac]

Just took ownership of a 1620 with a FEL. Low time unit but for some reason the rear 3pt lift will not lift by using the position control lever. If I position the Manifold Block to the 3pt position it will not go up....however If I position the Block in the Aux position and and raise the position control to the up postion it will go up if I work the FEL up and down lever. Sounds like the screw valve in the Manifold block must be messed up....anyone heard of anything thing like this before? Thnaks