I can tell you what I did when mine stuck, of coarse with the kind of luck I have all 4 stuck at the same time. 2 rear was down, 2 front was up.
1st Rear then Front- Got under, used WD40 on all the exposed threads and made sure they was soaked first then sprayed a little up into the spot where the thread passes through the grearage, waited about 2 hours to give it a chance to work, tried to use the manual crank handle but just would not seem to break loose, put a socket and breaker bar on it and got it to move, cranked it until the threads that was not exposed was, the electric took over from there, sprayed the threads that was not already done, left for a few days until dry. Then I went back under and this is where you will need to use your hands so use rubber gloves, covered the threads with lithium grease as it is water resistant, bearing grease is also water resistant but lithium works better. DO NOT just put it on in globs, you actually need to spread it all the way around and down into the groves, after going through all that trouble run your jacks up and down as far as you can to make sure the grease gets up into the gears and is well spread on the threads, wait 12 months and do it again as the rust will have been loosened and mostly gone, after that once every 2-4 can do for repeat. I did mine as I have posted and at 3 years still had a pretty good coverage of grease on them, just looked at 5 years was over due and needed it so I did it, which tells me I need to do it every 4 years. I have never had a stick since then, NOTE: the thing about anything that has threads and is exposed to the weather they do get rust and will bind or seize up any nut or threaded object that is threaded onto those threads. Then you run the risk of if not breaking loose to breaking the threaded rod.
Good Sam Life Mem
NRA, DAV, PGR, DRA