We just bought a 2006 Viking 2308ST pop up. This is our first camper. The crank is in the back and the rear left corner does not lift when cranked - the other 3 go up great, but we can push up that corner. Problem is that it gets up a couple feet and then the crank can’t be turned anymore. It was VERY hard to turn too. It goes down with no issues. Any idea how to fix either of these issues?