Here's what someone just posted this morning in the Kioti fb group:
"Just an update from posts from approx 1 year ago regarding DK models with hydraulic pump cavitation, there is a service bulletin for this, its called “DK hydraulic pump noise reduction kit”. I had this repair done at my dealer...
Yeah we are definitely talking about the same thing. I had a video awhile back that you can clearly hear that sound. I'll see if I can find it.
Edit: Found the video I made, but it won't upload on here due to improper formatting.
Mobile 424, but others have used Shell, Kioti, and the usual other brands and have said the odd noise persists. This topic has come up a few times in that fb group.
I can answer that with unfortunately not. I changed my hydraulic fluid at 50 hrs and then had to change it again due to a major hose pinch where almost all of my fluid leaked out (awful...). The noise continues after both fluid changes, and I've heard others say the same.
I wish I knew. It doesn't sound like anyone does. There's a dude in the Kioti Tractors USA Facebook group that wigs out about it a lot. I guess he worked on pumps for a living (can't remember what type of pump) and he is really worried about it ever since his started doing it.
It really is...
I believe I know the sound you're referring to, as my DK4710 started doing that around 37 hrs. It's very common amongst recent model DKs in the Kioti Facebook group, but there is no solution. The common belief is that it's hydraulic cavitation. I just hope it doesn't cause hydraulic pumps to go...