No power steering when turning left

What is your question?

At low speeds, I can turn right perfectly, but no power steering for a left turn. Hydraulic pump pressure seems OK. This problem just happened with no symptoms leading up to it. I was told that the gearbox is binding (but no one can tell me what is broken in it) and must be replaced and that the hydroboost must be replaced and that the front differential VIN tube/gasket is leaking and must be fixed/replaced. Does this make sense? Val