[guymd]

If the engine is running, then shouldn't the steering box be under the same load as if you were driving? The difference seems to be only that the wheels aren't rolling. Perhaps the problem is something rubbing repeatedly, such as a brake rotor touching the pad as it turns, if the calliper isn't fully returning to the open position or if one rotor is a tiny bit warped. It sounds like something I've experienced with other vehicles. And it might happen only when turning in one direction. Maybe you could try spinning each front tire separately with the front jacked up, but I don't know whether it would require the weight of the car to make the noise.