My boys and I are agreed. Let me tell you my story. Got a couple of them.
When they delivered my BX1860 it whined horribly!!! Dealer said I'd get used to it. No way. One day I found some drip marks on my shop floor. The value of parking your tractor on clean cement floor cannot be underestimated. Tracked down a finger lose hydro fitting. I was livid. That shouldn't have passed QC at Kubota. Anyhow, tightened it myself. I reported it to both Kubota and my dealer.
Noticeably quieter!!! Hurrah.
Fast forward to this early spring. I added a FEL to my tractor. I had to add about two quarts of fluid to bring it up to snuff. In the excitement, I forgot, (my bad), to pick up some SUDT when picking up the FEL. Grabbed some generic premium TSC fluid that "meets Kubota udt specs". Thought to myself, "it'll be ok, it's only a couple of quarts out of almost 4 gallons. WRONG!!! That son-of-a-gun foamed and whined like an over tired 3 year old. Dang it.
Stopped by Kubota, picked up 4 gallons of SUDT and changed the entire system out. Cleaned the screen too. You know what's next!! Silky smooth, quiet as ever can be expected, and no foam. Yup, big believer in SUDT. I'm good now for a couple hundred hours.