If there was a way to take them off the camper, I'd do what I did with an Atwood that got stuck on me.
I took it off and then drilled a hole in the center of the bottom of the foot and flipped the whole thing upside down and filled it with ATF, plugged the hole and then flipped it back up right to sit.
Once I finally got it broken free with the crank handle after much sitting and fiddling, I emptied the atf and put in a liberal amount of diff oil in it and released it and left it in there.
The jack never worked perfectly again, it still had some issues with the drive mechanism if too much load was put on it (if the jack got ahead of the other it would start to slip/bind until the other jack caught up), but it worked well enough to keep using till I got ahold of a replacement unit and now that one is just a parts jack.
Atwoods unfortunately weren't designed to come apart so I couldn't do a proper disassembly and wire wheel cleaning and bearing replacement and then coating all of the threads in moly.