I have the same furler and experienced the same symptoms so last winter I took the whole thing apart, figuring that it couldn't get more broken than it already was.
When I took the bearings apart, it appeared to me that the balls were alternating stainless steel and some kind of plastic. The plastic balls were considerably smaller than the stainless balls. I assumed this was from from wear, the effect being that the larger balls would ride up on top of the smaller ones and jam, preventing the bearing from rotating.
Still figuring I had nothing to lose, I replaced the balls, regreased, and put everything back together which was a fiddly, finicky task, but it operated like new until I found the corresponding single line furler drive unit at a salvage outfit and replaced the continuous line drive unit.
I still have the continuous drive unit, but it sounds like dmax has one much closer at hand for you, if needed.