Looks good GP!!
Locked and unlocked - I always thought they were in the locked position on our rigs?
The fan only locks up when it gets to the preset temp designed by the manufacturer.
When it sits overnight and you start up, it can take 15 seconds to 1 minute until the clutch can redistribute the silicone fluid back to the fluids normal disengaged operating condition.....according to the shop manual.
Wiki http://en.wikipedia.org/wiki/Fan_clutch
Detailed version of how the fluid actually works with the bimetalic "clockspring" thermostat
http://www.howstuffinmycarworks.com/Fan_clutch.html