strange landing gear retract problem

Usually it works just the opposite: the legs come up but don't want to go down and raise the trailer.

I would pull the top cover on the leg, and actually check to make sure the bevel gears are working as they should. These are very simple mechanisms, so there isn't much to go wrong. If the bevel gear is turning and the jackscrew is turning, then it would appear that the jackscrew threads are messed up or the thread insert that follows the threads. But that doesn't really explain why it works down but not up. I'll have to admit it has me stumped.

Please post back with the solution when you find it. I'm dying to know what was wrong.

The cross shaft is turning because I have no problem getting the gear to go down and lift the trailer

I'd check the bevel gear, and/or the jackscrew threads. It sounds like the bevel gear is spinning, but not transferring rotational force to the jackscrew. With enough force on the leg, it may work a little. The bevel gear pin could be sheared and/or the bevel gear teeth worn. Of course this is assuming the cross shaft is turning like it should.

The thrust bearing at the top of the jackscrew!

EDIT: After looking at that in print; I will point out that those are actually the names of the parts within the landing gear leg.

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