OK, heres what I found when I pulled the side case off. First I only pulled off the side with the clutch in it, Just pulled it off. I did not disassemble it. I.E. removing the set screw and driving out lever separating it from the shift fork. When you pull the case off, if you stand the winch on end, be prepared for the dog clutch, spacer and bushing to fall out. I could not find anything that would keep the clutch from disengaging. So I reassembled it. By your self this is difficult if you dont follow the TM. I had to try several times to stack all three items in the proper order, with the keyways lined up and flip it over while holding the clutch lever tight to hold everything in place and not have things fall out. One thing I discovered is the threaded rod on the bottom of the winch needs to be removed, that way if you dont have the keyways lined up you can rotate the case to get them to line up and everything will drop into place.
I did discover that my drum brake on that side needs to be replaced. The lining has broken free from the backing and I'm also missing the spring that goes behind the adjusting srew for that brake.
What I did learn by this process is that the last time this winch was disassembled/reassembled I think the two cases were pulled together to tight and that why it would not dissengage. The TM says to make note of where the inside nut on the threaded rod is in order to locate where the side case needs to be reassembled to. In my earlier post I said I could turn the drum only so far before it hit the clutch. If I went slow i could feel it hit then I could back it up. If I went fast I could feel it wedge itself tight and I had a hard time backing it up. When I reassembled it, I backed that nut on the threaded rod out just a slight amount and then tried to spin the drum again, now it would spin but I could hear the drum contact the ears on the clutch as it spun around. I think if I spread the case another 1/16 of an inch or so it will clear and I believe there is enough play in the holes in the top and back plates to to this along with play in the front rollers. DH this is where I would start with your winch if you cant get it to disengage. If the winch is not on the truck pull the rollers off completely then loosen the top and back plate, then loosen the nut on the outside of the threaded rod on the bottom and turn the inside nut to spread the cases.
While we're here, is it possible to clean up the rust off the drums sealing surface? I know if I dont clean it up that rust will tear up the seals.