My shower valve seem slightly different than the one speedball1 has pictured but the information was on the money. After I pulled the retainer clip I had to remove a very small split ring hidden inside the valve body (it was directly underneath the retainer clip). The valve body was stuck pretty tight so I used a little penetrating oil to lube the body and dropped a small nail through the hole in the stub where the handle attaches to allow me something to grab onto to pull it out without damaging the stub. I had to work at it a little but is came out OK. I cleaned up the valve body with some fine emery cloth, lubed with silicone gel and put the assembly back together. I did have to work the valve off and on to get it to seat properly at first. It wanted to spring out into the on position until I did this. I had to turn the water back on to get this quirk worked out completely.

On my valve the hot/cold stops are just a sleeve that the handle contacts to prevent turning the valve 360 degrees. If the hot and cold are reversed, remove the handle, rotate the valve 180 degrees and re-attach the handle. That should fix it.

I'm going to look into a new valve body from a local plumbing supply house that deals in older and hard to find parts. I've got another on os these that should get the same cleanup, and lube treatment.

Thanks speedball1 for the help!

Could you give us a brand name for your shower valve?