If I recall correctly, yes it is threaded. I believe you take a large wrench to that outer nut that your red arrow is pointing to and the whole thing screws out. I believe it was 13/16"? It's been a while. Wish I would have taken better pictures of that step.
One things for sure, watch that little purple plastic tab on the end of the rooster comb when you're trying to remove that sensor, if it looks like anything's gonna torque and break, STOP what you are doing.
Last edited by aim4squirrels; 10-27-2009 at 12:13 AM.