Sounds like your outer clutch bands are sticking. Easy fix.
Pull the cover where the hydraulic line goes into the clutch, exposing the brake and clutch bands. give them a tap with a small hammer to free up the rust on the clutch bands. There are adjusting cams that allow you to limit the travel of the bands. Loosen them, turn them to the flat side and you'll be able to take the bands off to clean them with some sandpaper( just give em a quicky scrub). Replace them and put the stud back that goes from the hydraulic cylinder to the bands. Set the cams so you have about .020" between the bands and the drum ('bout three/four sheets of paper-not super critical)
Put the hydraulic line back on and bleed it, letting any air in the line out. Pump the lever and you should see the clutch bands move to the drum and it should release when you release the lever. The brake will take over from there.
Sounds complicated, but it really isn't.
Lack of use is the worst thing for Gearmatics- run the winch a few times whenever you can. And tarp it to keep it dry! The things hate water .
Let me know if you have any problems or success.