Can't Remove Stem valve

Hi, my outdoor frost free faucet is making a racket. I went to remove the stem valve to lubricate it and I can't for the life of me figure out how to get this done. I've remove the knob, the packing nut and I would think the next step is to remove the large thin hex looking nut in the below pic and the whole assembly should slide out, but it doesn't appear like this thin nut is separate from the rest of the hardware. It appears to be one unit all the way through. I have tried turning it and it hasn't budged and I'm afraid of doing some damage. Should the hole faucet rotate? on the other side of the wall, I can't tell if it is threaded on the pipe permanently or not. So I am afraid to start turning the whole faucet assembly. Appreciate any help. Thanks. JT

It will unscrew. Use two wrenches. One to hold back on the faucet the other to remove the nut. Put the packing nut back on it has nothing to do with removing the stem. The noise your hearing is most likely coming from a loose washer on the end of the stem.

Well I'm an amateur but I just removed that nut on my hose bib and the long stem with the faucet washer came right out. I'm hoping the seat is ok as I don't know how I would get that out.

For you I would put screws into the siding where the two side notches are in the face plate then get a crescent wrench on the the valve body to hold it from turning and lastly get a box wrench that will completely encircle that nut and unscrew it.

Pros please chime in if I am off base, but this worked for me.

Looks like a 'frost proof" hose bib, which has a longer stem to prevent freezing...The nut you indicate in the picture's the only one you will need to loosen...use a larger crescent wrench and hold opposite rotation(back up) with a smaller pipe wrench.