Help removing shower stem

I hope someone can help me, as I am a newbie, to this forum and plumbing. I believe I am working on an American Standard shower faucet, trying to fix a leaky faucet. There are three knobs - Hot, Cold and diverter. I removed the hot water knob and the outer sleeve. Then I removed the putty and cut some of the surrounding tile to see what is behind the stem, only to find out that there is No hexegon nut. There was an attached sleeve on the stem that I kinda broke off, trying to turn it, it broke off at the base showing a couple of threads. It looks to me that this stem screws into the brass fitting somehow. How do I get the stem to unscrew with out messing everyting up. Please keep in mind, there is nothing on the outside to unscrew, somehow it screws into the fitting.

Get some plumbing sockets and use a large crescent wrench for leverage. Don't forget to turn off the water to the shower first.

There is no outside nut for the sockets to unscrew. It is round, looks like the stem screws into the brass fitting.

Why don't you post a photo. I've never seen a stem that you couldn't unscrew with a socket. Maybe you just can't see the hex part or that broken sleeve is covering it.

If there really isn't a hex part, the only thing I can think of is to cut away some more tile and use a big old vice grips to unscrew the stem.

Is it more than 30 years old? I could be wrong but.......

Look again and see if you can see a very shallow hex on that brass stem housing. You can use one of those wrenches shown above.

Don't try it without the packing gland in place. If it's the faucet I think it might be, that's where the running thread tail piece holds the chrome escutcheon, that you had trouble with .