Most of the time...
... getting drums off that are stuck is due to the grease in the drum/race getting old, gooey and hard. Once you remove the top cap of the winch, try spraying the center hub with a penetrating oil/spray and hope some is making its way down to the race. On a previous boat with Maxwells, I used PB Blaster and then put a piece of wood at the base of the winch and inserted a crow bar and levered the drum off VERY carefully. I kept moving the piece of wood that was under the crow bar (to keep from marring the gelcoat) and levered it all around the base. It finally came up. The grease inside was hard as a rock and I doubt the previous owner ever serviced them. I soaked all the the parts in mineral spirits for a few hours and cleaned them up with an old tooth brush. Put some white lithium on the parts and reassembled. Good luck.