I've gone and redone the procedure another 2 times. I believe the problem is elsewhere. Sometimes I would have pressure on both couplers and sometimes I would have no pressure at all on either side. I have connected a hose to the outlets and no oil is flowing but the tractor makes a distinctly different sound when the lever is being moved. This one has got me puzzled.

I will take the SCV from the other side of the tractor and interchange it with this one and see if the problem moves with it. I've never had such a hard time finding a problem before.

Is it possible that something with the rockshaft could cause this problem. The problem SCV is on the left hand side of a JD 4440 and from what I can see it is being fed from the rockshaft. I'm not sure but I think that the right hand side SCV gets fed first and then heads towards the rockshaft and then to the left SCV. If something is not right on the rockshaft then maybe the SCV doesn't get fed, but it doesn't explain the change of sound coming from the tractor. Strange.