Just bought a Deere 4520. I already had a 4500 and love it, just wanted a little more horse power for my tiller. My question is I notice when I turn the hydraulic steering whines pretty good on the 4520, is this normal? Also, I think I have a 3 point valve issue too. When I have my tiller on it will slowly settle over a couple of hours and even when the tractor is running it drops a little and then it picks it's self up; like every 10 seconds at idle. Is that an easy fix? My 4500 will hold the tiller up when it is not running and never cycles while running.