This thread is supposed to be about squeal noises from DK-40 series tractors; it would be appreciated if we could move back to the original topic to keep consistency for those trying to solve this extremely annoying problem.
I will add one answer to a question I was asked about backhoe thumbs, earlier on in the thread; I have been offline so this is my first chance to respond.
I have a MIE backhoe thumb, as my signature indicates, from Michigan Iron and Equipment. It is NOT hydraulically operated, and I use it infrequently, thought it is up to the job of doing what it is designed for.
My answer to picking things up is an Igland GR-20 LOG grapple. I mention this because I have a LOT of trees, brush, stumps, etc to move, burn and deal with. It is compact: 36" wide x 42" max jaw opening, and it is very HD construction, for a total of 356# weight, so it will not adversely affect lift capacity of the loader.
The SQUEAL issue and a hydraulic valve not allowing proper flow dynamics after the fluid warms may very likely be the center of the problem for the affected tractors. How Kioti solves this problem is currently the question at hand; unfortunately there seems to be only quiet coming from them and no answers or response in general to this issue. If cavitation and other adverse effects are indeed occurring then the squeal is not just annoying it may also be doing damage to the tractors exhibiting its symptoms in the form of the squeal.
My tractor is going to the dealer, hopefully soon, to have the grapple's hydraulics installed, and a second rear remote valve to operate the jaw of the grapple; if Kioti ever gets its 'new 'puter' system running effectively!? I will ask about having the pressures tested for variation from normal.
I will make an attempt to get another video done of the squeal in my DK-40 that could be posted, possibly on You Tube, to reinforce the evidence that this problem is not isolated to one or just a few tractors.