DK40SE Squeal When Moving in Reverse.

[tnewbern]

Hey grsthegreat I not do discount your squeal or your ability to live with it but and here is the big but. I don't think you are experiencing what the rest of us are. Lucky for you and for you sake I hope it does not progress to what we have.

There is no muting or ignoring the squeal. The AC fan on full and the stereo cranked to discomfort and you are not going to miss it. Still stands out like nails on a chalk board. Over 500 hundred feet from the house deep in the woods all the windows closed and my wife complained every time I used the tractor.

There is a huge difference between a whine and a squeal. Yes HST transmissions are know for being noisy and tend to whine. This is not the case here. You can hear the normal whine of the HST before the oil heats up. The typical HST whine changes pitch and levels with RPM's and speed. The squeal is a perfect constant pitch every time slow or fast.

If you heard it or your tractor made the noise you would not I repeat NOT for one second question it. Nothing anybody could say or do would convince you that it is normal and everything is OK.

 

[grsthegreat]

Hey grsthegreat I not do discount your squeal or your ability to live with it but and here is the big but. I don't think you are experiencing what the rest of us are. Lucky for you and for you sake I hope it does not progress to what we have.

There is no muting or ignoring the squeal. The AC fan on full and the stereo cranked to discomfort and you are not going to miss it. Still stands out like nails on a chalk board. Over 500 hundred feet from the house deep in the woods all the windows closed and my wife complained every time I used the tractor.

There is a huge difference between a whine and a squeal. Yes HST transmissions are know for being noisy and tend to whine. This is not the case here. You can hear the normal whine of the HST before the oil heats up. The typical HST whine changes pitch and levels with RPM's and speed. The squeal is a perfect constant pitch every time slow or fast.

If you heard it or your tractor made the noise you would not I repeat NOT for one second question it. Nothing anybody could say or do would convince you that it is normal and everything is OK.

and i hope i never have to. im just saying that i have a little of it on mine now. i am chatting with my dealer right now about it. in my particular case i could live with it, im not saying that you need to live with yours. id like mine fixed if theres a solution. im just worried that it can lead to some other kind of damage.

 

[tnewbern]

Well guys bad news the banjo bolt change did not relieve the squeal.

I went back to stock this morning and started the diagnosis. The squeal started occuring when the hydraulic oil temp reach about 90 degrees running at 1500 RPM's. While backing and squealing if I raise the RPMS over 2000 the squeal stopped after about 1-2 seconds. Once the oil reached 110 degress the squeal was there full time.

Next I changed the banjo bolt and tried again. There it was no difference so back to the drawing board.

I put the bypass line back in routing it in a better way as a permenant feature on my machine (until its resolves atleast). The squeal is again gone and the tractor much quieter all around. After hearing the HST with the stock line I can't believe how much quieter it is with the new soft line. Its not just the squeal there is significantly less noise even when just sitting idle. With the stack line there is a constant whine which gets louder when moving forward or reverse. Hearing the noises again I can understand why I thought the HST sounded strange after the bypass install. The system is so quiet that you can hear the gears and pump in the trans turning.

I really think the problem is in the low pressure charge side of the HST. Either there is low flow from the pump, a bad attenuator (yes that is right and its purpose is to remove high frequency noise from the oil in HST systems and usually called an accumulator), a bad charge valve, or leak in the HST. I guess my next test it to find a flow meter and take a look at the volume of fluid entering the HST.

Anybody else get a chance to test their charge pressure?

 

[Hoosier Hay Man]

I knew an engineer working for a compnay that built hyrdrostat steering sytems. They had an issue with New Holland combine owners complaining about noise in their steering. He told me they did in field fixes with rubber lines instead of steel. I know a hydraulic whine can be very annoying.

 

[Coyote machine]

tnewbern,

Are you saying the 'softline' you now have installed is the same one kattywumpus has on his: the one Kioti designed a while back? Or is it your own custom rig?

Thanks for posting the test results. Sorry they didn't get you/us what we want but it's still progress.

 

[tnewbern]

Mine is a custom rig but very similar. I will try and post details and pictures as soon as I can.

 

[Coyote machine]

Pics would be great! Components used would be useful too, if possible.
Maybe some of us can use what you've come up with until Kioti or someone comes up with a more permanent solution for all of us. Even if all we accomplish is to squelch the squeal; that would be some relief in the interim.

 

[Tshaw]

When you post the info I'll install the equivalent into my bobcat ct335 and see if anything happens... mine is tolerable but annoying, and can be heard through 300ft of forest...But my grapple keeps me smiling!!!

 

[grsthegreat]

I got an email from my dealer..hes contacted Kioti and they ", they want to try a new hst filter first. There is a valve in the filter and they think what may be happening is under lower flow the valve is a little to strong causing the issue"

since i didnt have this BEFORE i changed my hydraulic filter and fluid, who knows.

ill give it a chance.

 

[Coyote machine]

I got an email from my dealer..hes contacted Kioti and they ", they want to try a new hst filter first. There is a valve in the filter and they think what may be happening is under lower flow the valve is a little to strong causing the issue"

since i didnt have this BEFORE i changed my hydraulic filter and fluid, who knows.

ill give it a chance.

Interesting concept, but unless the factory installed filter and the one they are going to give you now are different I doubt it will do much to solve the problem. For instance I developed the squeal noise at 10 hours on the original factory filter and have since changed the filter at the 50 hr. svc. and no change in frequency of noise's presence, etc. If they have an entirely new filter that they're going to try then I'd have some hope for a possible change in symptoms. Are you certain your tractor is exhibiting the excessively loud squeal the rest of us are experiencing?
As Tnewbern mentioned earlier it is an unmistakable and relentless noise that is audible for a LONG distance.

Let us know how you make out.

Thanks,
CM

 

[tnewbern]

I second the filter thing. I am on my 3rd filter and it made no difference. I hope they are not charging you for one.

If they are talking about a valve I think they mean the filter holder. In a pressure filter like these there is usually a bypass. This allows the oil to bypass the filter if the restriction is to high to keep the filter flow blowing out. I look when I had mine apart the last time and I did not see one on this unit. The filters themselves are very heavy and strong to withstand any pressure so maybe the bypass is not necessary.

To finish this off I also questioned the filter many posts ago. Like at some point in time they changed the vendor or micron rating. I don't know about the one that came with the tractor but the other 2 were from the same lot.

 

[tnewbern]

Ok so here is what I have done. I am not sure if this would be Kioti sanctioned. This patch replaces the hardline on the side of the HST to the top of the filter. Kioti has a fix similar to this as shown by kattywumpus. He got a differeing result than I did so be warned your results may vary.

First remove the 2 banjo bolts on the short L shaped hardline on the HST. One of the bolts is on the HST and the other on top of the HST filter. Use a pan under the filter as you will loose a small amount of fluid.

I used a straight M18 to #10 JIC fitting on the side of the HST. Just screw it in be careful not to over tighten. I used a right angle M18 to #10 JIC fitting on the top of the HST filter. I pointed the outlet to the rear of the tractor. The M18 thread is the same as the banjo bolt and what goes into the tractor. The #10 JIC is what goes to the hose.

I had a 4 ft section of (2000 PSI) hose made up for testing and decided to use this instead of buying another. My hose is 4 ft plus the ends so its more like 4.5 ft overall. This hose is rated for 2000 PSI working and 8000 PSI burst, this is the low pressure side of the HST so 5000 PSI is not needed. This hose has if you did not guess #10 JIC fittings on the ends. I am sure you can use a different lenght and run it a different way but I kept with this hose for 2 reasons. The first is I had it from on hand from performing tests bypassing various parts of the circuits. The second and primary reason is that it worked. I know kattywumpus has this softline bypass and did not get the same result. It might just be the lenght of the hose changing the circuit resonant frequency. The first time I used this was while testing the charge pressure at the HST inlet. If you don't remeber that was when I found the banjo bolt mismatch. When the noise dissapeared I removed the test T and made it a temporary fix until the banjo bolt arrived. Since the banjo bolt replacement did not work back goes the softline until a solution is found.

I ran this hose straight out of the HST under the floor panel along side the AC hoses. I then looped it around toward the front of the tractor around the little toolbox bracket and back toward the rear. Once I started heading back I feed it up and over the wiring harnesses and plugs. Once it exits I ran it down and around back toward the front of the tractor into the HST filter. I am sure this sounds confusing and you can vary this as you see fit. I originally had this in a different way. I was not happy with the way it was for a permenant solution as I spend a lot of time in heavy woods. This way it is tucked in very nicely.

Let me try to word it differently. Basically the hose runs above the wiring and plugs front to rear of the tractor along side the HST. It loops down and out away from the tractor around the toolbox bracket then back to the HST on the front side. It loops down and around the rear set of electrical plug into the right angle fitting on the HST filter.

I will post pictures this weekend.

 

[grsthegreat]

Kioti is supplying a new filter free of charge. My dealer even said he'd drop by and install it if i didn't want to do it. (ill do it). I'm not sure if its an upgrade filter or the same as i bought before...ill wait and see. I'm getting a definite squeal, more noticeable as the temperature outside raises. I didn't have it before the oil change.

Ill try this and see if it does any good.

 

[acme97]

Intresting read. I just got my DK50SE HST and did notice a slight noise when going backward. Since I'm 500 miles away I can't be sure it's the same thing you guys are talking about. A suggestion: Has anyone tried to record (audio) the sound and upload it? That might help others that think they have something similar. Just a thought.

 

[Coyote machine]

Intresting read. I just got my DK50SE HST and did notice a slight noise when going backward. Since I'm 500 miles away I can't be sure it's the same thing you guys are talking about. A suggestion: Has anyone tried to record (audio) the sound and upload it? That might help others that think they have something similar. Just a thought.

Yes, Kattwumpas posted a YouTube video of the noise, but it's somewhat hard to discern due to his being a cab tractor, and the sound is somewhat muffled as a result. It should be linked early on in this thread....
You're 500 miles away from what? If you're asking if I can hear the noise from my house, the answer is no.

 

[acme97]

Yes, Kattwumpas posted a YouTube video of the noise, but it's somewhat hard to discern due to his being a cab tractor, and the sound is somewhat muffled as a result. It should be linked early on in this thread....
You're 500 miles away from what? If you're asking if I can hear the noise from my house, the answer is no.

:laughing: That was funny! No I meant that I'm 500 miles from my tractor, so I can't go check it. I only get to go play every 6-8 weeks because my lovely bride is in the USAF stationed in DC and like any good spouse I figured I better go with her. I'll have to find the video then to see if it's like what mine is sounding like.

Found the video - my doesn't have that sound, at least not yet. I'll keep monitoring just to make sure.

 

[kattywumpus]

Finally got chance to get some reading. Got the Charge Port pressure first, will get test port next.

HST Charge Port Pressure
Outside Temperature 90
.................Engine 600 psi : 300 psi Gauge
Temp............RPMs PSI : PSI
Outside Temp 1000 220 : 235
Outside Temp 1500 xxx : 260
Outside Temp 2000 255 : 275
Outside Temp 2800 255 : 285

 

[kattywumpus]

Can't get reading for test port since I have the wrong fitting.

After working tractor for over 2 hours, clearing land:

Reading with 300 PSI Gauge at HST precharge port.

RPM.....PSI
1000 . 220
1500 . 250
2000 . 260
2800 . 270

It appears on average 15 psi drop.

 

[kattywumpus]

I will post pictures this weekend.

Remember pictures when you get a chance.


Interesting note: Since adding the tee to the soft hydraulic line between the filter and HST precharge post the squeal occurs dropped off considerably. Saturday and Sunday it only occurred randomly when coming to stop or when initially going in reverse. In the past with the temperature in 90s it always occurred going in reverse. In addition to installing tee I top off the hydraulic fluid.

On the tee port for the gauge I installed a 90 elbow and the 1/4” quick disconnect so I could easily connect and disconnect a pressure gauge. It appears the 300 psi gauge is more accurate so 36” ¼” soft hydraulic line was connected to it so I could temporarily mount the gauge to the windshield.

This allowed me the monitor pressure while working the tractor. Normally there was a greater pressure drop going forward then reverse. When the squeal did occur the pressure did not appear change much from the normal for reverse but the gauge needle did vibrate much more.

I wonder if adding these additional components created shock suppressor for the pre-charge hydraulic circuit?

 

[northcreek2624]

Have you considered trading the tractor in for a gear unit? I'm sure it's not what you wanted to do but,it may allow you to have a servicable(and quiet) tractor and also some sleep at night.
I can't believe that they are jerking you around like this...mike.