I had this happen to my tongue jack. When I took it apart I found the ball bearing destroyed in addition to a lack of grease. If your bearings are intack, repack the bearings, slather everything in fresh ball bearing grease and back away slowly.....
to repack a bearing, put a dalop of grease in the palm of your hand and drag the bearing trough the grease until it is force out the other side, spin the beaing a couple of times and repeate. General pourpose grease at the auto parts store is fine for this application but if you want to upgrade, look at the synthetic "disc brake" bearing grease.
2010 Surveyor SV 291
06 F250 4x4 crew cab PSD
1 DW, 1 purebred mutt, 1 ninja beagle
Nights camped in 2011: 19