The wife and I will move the truck suspension up and down by making a jumping motion on the bumper or hitch, only about 1 in 20 times will I actually have to do anything with the truck. She showed me that move the first time out, she said they had to do it all the time with their popup growing up. Greasing the ball doesn't seem to have any effect on the stuck phenomenon, it seems to be related to angle between truck and trailer and how much slip there was when putting the truck into park.