DK40SE Squeal When Moving in Reverse.

[Coyote machine]

Caver,
Even if it were to squeal on the lot, I wouldn't necessarily walk away if the price is right. And, you have a two year warranty covering things like the squeal issue, which Kioti is continuing to seek solutions to. I've got 300+ hours on my DK-40se/hst since last Oct when I bought it. The noise showed up at 10 hours and it has not caused any adverse effect that I'm aware of, other than the obvious noise annoyance. The DK-40 is a stellar tractor, and I state that having owned a DK-35se/hst for about the same hours and traded it for the 40 to have a better FEL capacity and other features the 35 could not provide. I was joking with my wife today about trading it for a bigger Kioti, so I can do some real damage. I told her later I was kidding- so she wouldn't worry.
If it were me I'd want to see evidence of the 50 hour and other service that was required up to the current hours on the tractor.
Good luck, post back results, and BTW, you're welcome for the update info- glad it was of use.

 

[caver]

Coyote

The deal breaker will be more along the lines of what he gives me on trade in.
He's a well known Kioti dealer and a good dude to do business with from my past experience.

My LB1914 TLB has less than 100 hours on it but out of warranty. Any idea what a dealer would offer? hahah:laughing:

 

[Mike476]

Very interesting thread that I've been monitoring for some time now. I don't own a tractor with HST and I don't have any knowledge on their engineering other than what I've read on this forum but I do have some experience with hydraulics.

Not sure if the relief valve CM mentions Kioti is considering for future model years is thermal or pressure but I can tell you that engineers try to avoid excessive heat in a hyd system whenever possible. Nothing earth shattering there I know, on some aircraft we route hyd return lines through fuel tanks to cool the fluid on return to the resevoirs, works very well.

The other thing we try to avoid are surges, hyd systems operating numerous control surfaces, landing gear etc are of course engineered so that systems operations, whether independently or concurrently, do not exceed the volume and pressure capabilities of that system. To do this there are several pressure regulators, flow restrictors, metering valves and check valves incorporated into each system. Again, nothing earth shattering there either.

What might be of interest is that on most older aircrat I've worked on whose systems are configured as stated above, there is almost always a surge suppressor in the return system just prior to the resevoirs. For the most part they are nothing more than a series of plumbing loops mounted in such a way to assist in absorbing shock loads when multiple systems are in operation simultaneously. What has that got to do with the HST problem?

The reason we don't want shock loads or harmonics in a hyd system is that fluids used are chosen for compressibility characteristics. Heat dissipation, surge suppression and harmonics are left to engineering.
Harmonics in those same fluids are felt throughout the system, and in aircraft whose autopilot sustems incorporate flight control load sensors etc, harmonics are not a good thing. Are HSTs as complicated in their engineering, probably not, but I would be a hard sell that over time they would not adversely affect the HSTs operation, but that is just my opinion.

All that to say that sometimes harmonics in hyd systems can be widdled down to something as simple as how plumbing is mounted, how increased temps in the fluid expand the plumbing that when cool don't exhibit any harmonic resonance. I would think if Kioti believes this to be the case they are likely more concerned with possible "cause and affect" issues down the road where the harmonics may actually cause premature component wear down the road if left unresolved.

Just my two cents, I'll continue to monitor this forum to see what results those of you actively pursuing a resolution get from Kioti, stay persistent and hats off to you for persevering!

 

[Coyote machine]

Fortunately for most of us our tractors are earth bound and are not likely to fall out of the sky if something serious goes wrong. A harmonic imbalance in something like a flywheel can and would likely do some damage to the system it is connected to eventually. A fluid harmonic imbalance caused by flow or pressure or whatever specific set of circumstances might also render damage but probably over a greater amount of time and not necessarily be catastrophic in nature.
Fluid hydraulics and their dynamics make for difficult to solve problems that can be elusive in nature. Piping, material used for such, and fluid viscosity and temperature are all factors, nothing new here, however, how these factors influence each other and the outcomes of the influence is what makes quick and easy solutions to things like noise generated and its consequences beyond just the annoyance of the noise as a symptom more difficult to resolve than something like a failed bearing as a result of lack of grease, for but one example.
I'm hoping that the current solution provided by Kioti/Daedong is sufficient to last the life of the HST transmissions currently inflicted with the symptomatic squeal. Time will tell, as with most things.

 

[quiturcrying]

Apparently all these engineers have no clue about harmonic noise and natrually assume it is more serious. I can and will tell you it is strictly harmonic noise and there is no damage to the HST unit! The rubber hose simply allows for a less abrupt flow and the rubber asorbs the harmonic noise. As for the drawing.... get a life! It is crude but effective.

 

[caver]

My dealer has not come across the problem but said he had heard about through internet discussions.
Just brought home a lightly used Dk40SE HST with box blade and Horst 3700 lb pallet forks. Still trying to get used to the hydrostat and the throttle lever seems backwards from my LB1914. I hope to have it over at my property in the next few weeks.

 

[Coyote machine]

Apparently all these engineers have no clue about harmonic noise and natrually assume it is more serious. I can and will tell you it is strictly harmonic noise and there is no damage to the HST unit! The rubber hose simply allows for a less abrupt flow and the rubber asorbs the harmonic noise. As for the drawing.... get a life! It is crude but effective.

So I take it you're speaking from a place of more education then a M.E or E.E.? Somehow I highly doubt it. You throw out wild statements about engineers not knowing anything and yet you also want to tell us what is happening inside an HST transmission without backing it up with anything but your couple of poorly written sentences?!:confused2: You list no tractor or anything else of real identification as to who you are in your profile, and your general tone is condescending and basically rude- but hey, with a name like quityrcrying why doesn't that surprise me? I also take it you're referring to the original drawing supplied by Kioti to various Kioti tractor owners experiencing the problem detailed on the preceding bunch of pages prior to your post. No one is even speaking of it but you, so you're welcome to take your own advice and get yourself a life.
Why are you even posting about this thread unless you have an HST transmission affected by the issue?

 

[IslandTractor]

Coyote, don't bother squabbling with Quiturcrying. I note that he joined just last month and from the four posts made so far clearly establish: 1) not a newbie, 2) not inexperienced with details of Kioti products including Mechron, 3) technically quite sophisticated on diesel engines (read the lubricity study he linked). I would hazard a guess and say he is either an experienced dealer in disguise or a Kioti factory rep. In either case, clearly he is operating incognito and will continue to hide his identity. I think it would be helpful to have someone like this participate under a pseudonym as the false identity permits him to be more honest and less diplomatic (which is a good thing).

Happy New Year Quiturcrying and welcome to TBN (in this guise). I hope you are what I think you are and that you continue to participate.

 

[Coyote machine]

Island, I appreciate the advice/warning, and I have the same sense about the guise/cloaking of the aforementioned participant. What I don't understand is what purpose does it serve for a dealer, for instance, to try to pull off these thinly and poorly contrived cons? Or, for a manufacturer's rep, for that matter. Yes, I saw the link to a study too before I posted; I just get annoyed by people playing stupid games when some of us are actually trying to get things done. You?

 

[IslandTractor]

Island, I appreciate the advice/warning, and I have the same sense about the guise/cloaking of the aforementioned participant. What I don't understand is what purpose does it serve for a dealer, for instance, to try to pull off these thinly and poorly contrived cons? Or, for a manufacturer's rep, for that matter. Yes, I saw the link to a study too before I posted; I just get annoyed by people playing stupid games when some of us are actually trying to get things done. You?

I don't see it as a con at all. Just an individual being more honest than they could if they were representing their dealership or company. "Off the record" will often get you a more honest appraisal than something that the speaker needs to explain to his boss.