Front end mystery on 2020 International HX520

so my truck makes a very strange sound, its part growl, grind and vibration. I haul logs in Northern California. I drive a 2020 International HX520. It will only do it pulling a hill under a load of logs and making a right turn. When I’m turning left, or steering straight, or going down hill loaded, it does not make a sound. It never does it empty either. My front wheels have been balanced, my front end alignment is spot on, my steering wheel feels smooth and does not shimmy when this noise, vibrations happens. My power steering pump does growl like it is low on fluid, its not. It also does not happen all the time, i could go a week without a peep and then the next load it happens. It also happens in levels of intensity, from mild to extreme. Any ideas