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