Cleaned off the area around the hydraulic head, including removing the oil filter canisters and #3 and #5 injector lines, to gain access to the center plug on the hydraulic head.
Removed the plug.
As suggested by David Doyle, I placed a small steel rod in the opening on the plunger and cranked the engine. The rod only moved an 1/8 of an inch, if that much.
A couple of light taps on the rod seemed to loosen it.
Cranked it gain and noticed a definite movement up and down, perhaps a 1/4 inch or more.
I compared the movement with an IP on my work bench and it appears to be all right now.
I'm replacing the coolant hose behind the oil canisters and replacing a broken plastic fuel return line this afterrnoon, so it probably wont be until tomorrow before I try to fire the engine up. Man, sometimes it's nice to find something wrong!