Slipping/Clicking Landing Gear

Thanks again for all your help. Since I got the trailer last year, I've not gone past the upper and lower extremes. I have the lower one painted, with room to spare, and I've never come close to the upper. I think the max that I've extended the legs are 12". No telling what the previous owner had done. One thing I've noticed is that when the gear slips raising the rig, it doesn't fall or lower slightly, it just stops going up. What keeps the rig from falling to the ground? Sorry for the dumb question.....