DK40SE Squeal When Moving in Reverse.

[Coyote machine]

Hang in there Coyote Machine.

If you can't wait then here are some details of the fittings. The banjo bolts are M18x1.5 thread. I used M18x1.5 to #10 JIC with #10 JIC fittings on a hose. The hose is rather long though as I use it for testing and did not custom fit it to application. Make some measurements. Remove the banjo bolts and hard line (see attache photo). Head to you local hydraulic shop and get some parts. If you do this please post pics of your bolts and hard line.

I don't plan to keep this setup and will reinstall the hardline with the new banjo bolt. If the pressures are correct and no squeal then I will publish that part number. To piece together a bypass kit will cost you over $100. The bolt is $10 and a simple swap with minimal oil spill.

Thanks for the details, Tom; I can wait, if I have to for the part #'s. I just want to help you help us all verify repeatability of 'killing' the squeal:thumbsup:

In the meantime, I have to go play with my brand new Igland GR-20 log grapple!! And then my new Woods BB72X 72"Brush hog mower...
I can't wait for the destruction to begin...

 

[dfkrug]

I am happy to report after many hours of hard work with the tractor I have not heard a single squeal. I am noticing some very faint chirping and whirring though. The chirps occur while accelerating or traveling uphill mostly going forward. Reverse is scary quiet. I don't recall hearing this before but its hard to say cause I don't recall listening for it. I can also here the gears whirring now and I don't recall that before. Maybe it was masked by other noises because it seems much quieter all around in the cab. This may just be paranoia or over sensitivity after the 7 Month ordeal with the squeal. The sounds are not loud at all actually they are quieter than the power steering and loader circuits. I just hope this is normal and not a sign of damage from the 100 hours of restriction, low flow and cavitation.

Good work, Tom.

If low charge pressure caused the squeal only in reverse, I still have to
wonder why you did not get any squeal in froward.

 

[dennis52]

Really impressed, not only by the engineering skills but the professional way you have presented your findings to the forum.

 

[Coyote machine]

Good work, Tom.

If low charge pressure caused the squeal only in reverse, I still have to
wonder why you did not get any squeal in froward.

FWIW, I get squeal in both directions, including forward.

 

[tnewbern]

I am not so sure its the low charge pressure as much as the restriction. Think of what happens when you force the fluid through a restricted opening. There is excess friction creating heat and sometime aeration. This flow is forced directly into the the pump pistons. Don't forget that forward and reverse are out of phase with each other and see things very differently Hydraulically speaking.

I am not so sure that forward is free from this disturbance. It might not present in the same way or oscillate. A slight difference in fluid dynamics and you go from a squeal to just noise. Take a bottle and disturb the air above the opening. If you get it just right you get a nice tone but if you are even the slightest bit off nothing but a bunch of huffing.

Sorry I have not posted the full details yet. I was debating letting go what I found so far for the very reasons unfolding. I decided to do so because I thought others may have some pressure numbers or able to get them. I was also hoping other would check and see it they had the same hardware from the factor. If others pressures are OK or have different hardware (squeal suffers or not) it would be vital information for formulating a solution. Hang in there everybody we have waited months already whats another week. The parts are on the way and hopefully a real solution.

Tom

 

[dourobob]

Hang in there everybody we have waited months already whats another week. The parts are on the way and hopefully a real solution.

Tom

Tom
I (along with many others here and hopefully the folks at KIOTI) admire your patience and your tenacity (along with your engineer's approach) in getting to the bottom of this aggravation with a solution that is valid, verifiable and repeatable.

Looking forward to what you discover in the next week.

Bob

 

[Kiotikarl]

FWIW, I get squeal in both directions, including forward.

I also get it in both directions, in reverse while snowblowing 15-20 inchs of snow this winter the tractor would also jerk in reverse. I also saw that while it was squealing if i would activate de loader joystick there would be less noise.

 

[dfkrug]

Don't forget that forward and reverse are out of phase with each other and see things very differently Hydraulically speaking.

I don't know what you mean by that. In the two different brands of HSTs that I have rebuilt, the FWD and REV circuits seem to be identical.
The flow direction is simply reversed by tipping the swash plate in the
other direction. I would have opened up a DaeDong HST, but I can't find
any broken tractors of that brand.

It makes sense that others are seeing squealing in both FWD and REV. Note
that the LOADS in FWD may not be the same as in REV.

 

[tnewbern]

I have not rebuilt any of these guys or for that matter any HST's what so ever. I am no expert and only speaking from a practical point of view but here is my reasoning.

The pump always turns in the same direction. The angle of the swash plate controls the direction and volume of flow. This flow is through a block and the 2 paths are not identical. The motor and pump are side by side and offset. The pump ports are oriented horizontal and the motor ports vertical. So the lengths and turns are directions are different and so are the flow dynamics. If the reverse circuit happens to be just the right length (tuned) to the disturbance it will oscillate (squeal). For forward the length is different and the circuit is no longer tuned to the disturbance and the noise is much more subtle as there is no oscillation.

This may not at all be whats happening and this is all theory. I am sure I am over analyzing this but its beyond my control I am obsessive. Even though my squeal is gone I can't sleep until I know why and can prove it. I will rest much easier when Coyote Machine and the rest of us are squeal free.

 

[kattywumpus]

Hang in there Coyote Machine.

If you can't wait then here are some details of the fittings. The banjo bolts are M18x1.5 thread. I used M18x1.5 to #10 JIC with #10 JIC fittings on a hose. The hose is rather long though as I use it for testing and did not custom fit it to application. Make some measurements. Remove the banjo bolts and hard line (see attache photo). Head to you local hydraulic shop and get some parts. If you do this please post pics of your bolts and hard line.

I don't plan to keep this setup and will reinstall the hardline with the new banjo bolt. If the pressures are correct and no squeal then I will publish that part number. To piece together a bypass kit will cost you over $100. The bolt is $10 and a simple swap with minimal oil spill.

Not trying to discourage your troubleshoot, and I appreciate all your work and documenting. Just be aware hardline banjo fitting between the HST filter and HST pre-charge port was completely removed from my tractor. This is the same fitting in your picture. This included the banjo bolts. This was noted in an earlier posts. Kioti engineer install a flexible hydraulic line with two 90s, which you can get for free from Kioti if you call them. Replacing the hardline banjo fitting did help but did not completely resolve the issue. For me the problem is very temperature dependent. During cooler temperature, below 65 no squeal, but above 65 degree it comes back.

Note: during Kioti visit the engineer did mention the possibility of replacing the pre-charge hard line between the cooler and the filter to further boost the pressure to the HST. My understanding from Kioti is the pressure at the HST in-port for my tractor is within specification, but since I don’t have a pressure gauge I can’t verify it. Since the in-port pressure was within specification Kioti didn't feel this pre-charge line needed replacing.

 

[IslandTractor]

Note: during Kioti visit the engineer did mention the possibility of replacing the pre-charge hard line between the cooler and the filter to further boost the pressure to the HST. My understanding from Kioti is the pressure at the HST in-port for my tractor is within specification, but since I don稚 have a pressure gauge I can稚 verify it. Since the in-port pressure was within specification Kioti didn't feel this pre-charge line needed replacing.

I am no engineer but am wondering if measuring the hydraulic pressure at the in port (or elsewhere) when the HST is not actually working (ie in the shop on a lift) might give a normal value because the pressure will be measured in a static state. If there is a restriction that would not affect pressure distal to the restriction unless there was also flow. Does it make sense that pressure might drop as flow increases?

 

[Coyote machine]

IMHO, you guys can kick theory around until you're blue in the face, but until I and others do a bolt change or something to produce a field repeatable change that eliminates the squeal, all we're accomplishing is blowing smoke.
I want to do something to effect a change in the outcome.

KW, I did have my dealer talk to Kioti and they sent a hand drawn version of your engineered flex line change and my dealer and Kioti both waffled on cost of who would do what for whom. My dealer so far won't do the suggested repair because he does NOT think it will accomplish anything.
I'm done arguing with him, but I am awaiting his report as to which size/length banjo bolt he finds they are currently using at the HST filter.

Just for the record, I want this fix for others as much as I want it for myself. I particularly I want it sooner than later so whatever damage is being done to our individual machines can be stopped before something happens that doesn't show up until later; likely after our warranty's are up, and then no one will be able to seem to tie cause and effect together without something like a suit and that colossal potential headache.

May the anti-squeal force be upon us all, soon.

 

[tnewbern]

Thank you kattywumpus. I know about the bypass kit (thanks to your previous posts) and tried to get it but was told its a dealer install only. Do you have a contact at Kioti to get the kit. Its a major pain not to mention expense to bring the tractor in for a simple hydraulic line.

I am interested to know what your squeal sounds like now (the before video was great and exactly what mine sounded like). I have my own bypass installed and I have not had a single squeal like before. The squeal used to be very pronounced and constant once it started. The squeal would continue until you stopped the tractor. This was temperature dependent for me also but I learned how to induce it before it got to the point of always there. Before I switched the line out after about 20 minutes of work there it was (maybe its a BEER:30 alarm). This would happen in the winter too but only after working for over an hour or more. I could also get this to happen with not tractor movement what so ever. Start the machine dig with the backhoe for and while then move. In warm weather it would not go away until you let the tractor sit overnight to cool down in the winter just wait an hour or so and you could go back to work.

Since I have installed my bypass I get an occasional chip, whir and growl but never and consistent squeal. These noises occur when the HST is under a load like going up hill or pushing into a pile. They are much more noticeable at low RPM's or in HIGH gear.

Part of what I am waiting to test are other restrictions in the supply line. If I install a low pressure gauge (500 PSI) inline at the side of the HST I get the expected 260-270 PSI. Before I removed the hardline I measured the pressure while bypassing the cooler at 450 PSI. That is a huge difference and a sign of significant restriction. Once I get the fittings I will repeat these test and perform a couple more to see if there are any other restrictions.

One of my concerns is that the bypass only changes the dynamic and the problem is still there as you are finding. I am not confident of the charge pressure at the neutral valves something seems funny on the readings. This is why I have not just said do this and all will be well. I don't think we will find or fix the real problem with trial and error. There is a real problem here and the squeal is only one of the symptoms. A headache is not a sign of aspirin deficiency and taking one (or two) only relieves the symptoms but the cause remains.

Keep the information flowing. The more we know good or bad (success or failure) the better our chances (including Kioti) for fixing this problem. I wish Kioti was more open to our feedback after all we are on the front line.

 

[tnewbern]

Sorry for the double reply I just saw the other posts.

I am with you 100% Coyote Machine and I was hoping you will be the Guinea Pig for the bolt test. I just can't tell you what to do yet with any degree of repeatability. A am like a kid a christmas wait for the bolts and part manual so I can advise. The theory is just there to pass the time and hear what other have to say.

I have tested the pressure while in the field not on a lift. This is part of the questions I have with the measurement at the neutral valve. I can get it to read 255 PSI but not under load. The pressure is stable now at the input to the HST but not at the neutral valve which is where they call for the test. This value is hard to read though without an expensive digital gauge as there is both 5000 PSI and 255 PSI present depending on the state of movement.

 

[robiefield]

I would like to chime in. I have a new 2011 ROPS DK40SE HST with 45 hours as of yesterday. I have the squeal which I think started around hour 4 or 5. It sounds exactly like what is in this thread and in the YouTube video. It squeals in reverse and when going downhill slowly in forward. It is a loud squeal. Doesn't seem to affect performance other than annoying the bejeeziz out of me... a brand new tractor making that awful racket.

It squeals in reverse and going downhill in forward regardless of 2WD or 4WD, with a load or without a load. It seems to be worse when it is hot out. I haven't had the tractor long enough to know how it does in the cold... only about six weeks since delivery. (I work the farm on weekends.)

My dealer in Christiansburg VA says he's never heard of it and can't comment on it until he sees or hears it, which he's about to do when it goes in for the 50 hour service. Anything I can provide him in terms of information will be helpful.

Like Coyote Machine I would love a part number so I could ask the dealer to try swapping the short banjo attachment out for the longer one with the machined neck--I will be happy to be tnewbern's guinea pig for the bolt test if someone can help me find a part number for the "right" (old style) banjo fitting with the longer shaft and machined neck.

Otherwise I love my DK40SE, but I really do hate that squeal. If a part number is not handy, can someone at least identify where the longer banjo fitting in the pictures came from, so my dealer and I might be able to find the part number from a diagram or something?

 

[tnewbern]

Hi rosiefield and welcome to the forum sorry it has to be this thread. You hit the nail right on the head with the squeal a described it exactly. Sounds like you get the same wow I never heard of that speech almost like it was rehearsed.

I got the exact same speech. I pressed back finally had Joe Shipsky my area Kioti rep come to my house less than 10 hours on my machine. Then he tells me he knows of the problem and was glad to finally hear the noise for himself. I wanted to return the tractor for replacement but was told this is normal break in and problem will go away on its own. About 40 hours later I reached out again the 50 hour service will fix it. I want a new tractor this is a defective unit. Don't worry sir Kioti will stand behind you and make this right. Now I called dozens of times to the purchasing dealer and never got a call back or answer from either. What to do I guess I will take matters into my own hands and here we are. I found a new dealer and got the same speech followed by a Kitoi has a kit for this problem. How can you have a kit to fix the problem if you never heard of it??? So the new guy reaches out for me and I find Kioti has no record of any report for my tractor. Come on your regional rep came to my house for damage control (a good show) but there is no record of this or even that I reported the problem. WTF!!!

Sorry I had to get that off my chest.

I can't believe how many people are coming out now with the same problem. Give credit to kattywumpus for leading the way and starting the thread after all he has suffered the longest. Maybe if we can get enough of use together we can make a difference.

Kioti are you listening!!!

Stop screwing around if you know whats wrong fix it. Issue a recall to those with the problem and replace our HST's. Not with rebuilds or remanufacture units these are brand new machines we want a new transmission. Problems happen its how you deal with them that defines a good company. Stop questioning and blaming your valuable customers and make it right. We are suffering and starting to regret our purchase. Not because its a bad product but the support needs major work.

 

[kattywumpus]

tnewbern,
I will get pictures of my flexible hydraulic line install and the hardline banjo fitting so we can compare. Sorry, I have no part # for this kit. My first recommendation is to submit a trouble ticket through Kioti website by the “Comments or Concerns” link. You can also email to customerrelations@kiotitractor.com. I would always follow it up with a letter with “Certificate of Mailing” to:

North East (or your area) Territory Manager
6300 Kioti Dr. Wendell, NC 27591

I find Kioti has no record of any report for my tractor.

Considering all a dealer needs to do is enter your tractor serial # in dealer website for a trouble ticket request or to see the repair and trouble ticket history for your tractor I find it troubling that Kioti say there is no report of this for your tractor. I have seen this web page myself.

 

[kattywumpus]

I am no engineer but am wondering if measuring the hydraulic pressure at the in port (or elsewhere) when the HST is not actually working (ie in the shop on a lift) might give a normal value because the pressure will be measured in a static state. If there is a restriction that would not affect pressure distal to the restriction unless there was also flow. Does it make sense that pressure might drop as flow increases?

Good point. I believe the pressure was measure while the transmission was in neutral. The HST petals were pressed but there was not load on the HST.

 

[robiefield]

I've been lurking here for years and used this web site heavily during my research and decision to buy the DK40SE HST. I saw this thread and asked the dealer who sold me mine if he'd had any units that squealed in reverse. He said he'd never heard of such a thing. So I ordered and took delivery of my DK40SE HST.

Kioti Customer Service via phone was polite but maddeningly unhelpful. They would not comment on the situation or verify the existence of the problem. They said to take it to the dealer and the dealer would fix it under warranty. I wanted more than to be told, "take it to the dealer and everything will be fine." After reading this thread, can you blame me? This is the dealer that's never heard of such a thing!

When I asked if they didn't have a database with other reports of this problem, or could I talk to a technician, I was stonewalled and told to just take it to the dealer. The dealer has to be the one to talk tech, I guess that customers aren't allowed to think on their own? Apparently the purpose of the Customer Service / Technical Support line is to tell owners to take the tractor to the dealer. She said the dealer would fix it under warranty unless I had done unapproved work on my own. (I've greased it and checked the oil so far.)

When I said that there were more than a few documented cases on this web site, I was told they "don't acknowledge or pay attention to those Web things because it is all just people's opinions and they don't participate in them at all." Yeah. So, good luck with all the web forum comments to the Kioti corp folks, cause I just got told the corp policy is to not acknowledge the existence of these forums, much less read them.

I live about fifteen miles from Wendell, but the response I got made me feel like I might as well be on Mars. This is most discouraging. Ay yi yi.

 

[IslandTractor]

Most of the posters on this thread did not live though the infamous loader cracks issue that affected the older style KL120/130 loaders. Looking back at those threads three or for years ago shows a disturbing similarity in Korporate Kioti's management style when something goes wrong. They bury their heads in the sand and reassure with vague generalities rather than providing specific updates. They finally resolved the problem and took care of everyone but boy did they screw the pooch on public relations. This is starting to sound like deja vu all over again.