Hst squeel from Hell

[Dude1234]

Had a question my rk 55 started making a squeel noise that is just the worst on the ears randomly if i use the auto button. I will be driving and whn i let off the accelerator it will continue to squeel. If i touch the pedal either forward or reverse the nosie will stop. The sound is different from the normal whining noise if you operate lets say in high gear.

If i opperate at high rpms i make the noise bearable but as soon as i throttle down when stopped you can hear it. It will even make the noise in the neutral position if i press the accelerator in reverse.

Tractor has 80 hours. Seemed to start after the 50 hour service. All fluids are spot on.

Any thoughts?

 

[MapleLeafFarmer]

often a sign of your pump failing or a clogging screen/filter

 

[oldnslo]

Were the filters changed at 50 hour service? If yes are they OEM or aftermarket? Some models of tractors are sensitive on what filters are used.

What type of fluid was used to refill the transmission?

At 80 hrs is it still under warranty?

 

[CloverKnollFarms]

TYM, which the RK is, I've heard from the best TYM pros on this forum, is quite sensitive to filters... They require a specific bypass, so aftermarket will be a crap shoot.

Which is why I used OEM

 

[Dude1234]

Thanks for the reply. All filters were changed at the 50 hour services. the big one is oem tym. the other was a filter next to the fuel tank is napa gold made by man which the oem was a man.

Correction* the sound is like a wooot or rooot noise that is in harmony. If i throttle up it goes away… i think…. I noticed if i stop on an incline the noise happens. Also noticed if i put the tractor in position 1 or 3 ,the botton on the dash that dictates how quickly it stops or rolls, that i could hear it wanted to do it but would immediately stop. I didnt play with it that much but its bizzare. I might just bite the bullet and through some new filter on maybe one of the two new filters are bad….

Question:
What screens? Is there other filters beside the two? I spoke two the machanic he said the transmission has a screen filter that a foot long that next to the hard line but i could not find anything on the part diagram. I think he may have been wrong…. Or confusing a different model.

Tractors still under warranty and the oil is the rk brand they recommend.

 

[oldnslo]

For clarification:
Is the noise present when you are not moving?
Does it make noise if range selector is in neutral and you press either forward or reverse pedal?

Do you or your dealer have the equipment to check charge pressure? Reason for asking is I suspect your HST is electrohydraulic pilot controlled so fluctuating noise could possibly be caused by charge relief being slightly unstable under certain conditions.

Since under warranty the amount of work you do is your choice vs seeing if dealer will check things out.

 

[Dude1234]

Is the noise present when you are not moving? Yes
Does it make noise if range selector is in neutral and you press either forward or reverse pedal?
Yes it will make the noise if I press either pedal down. Or if it’s already making the noise and I shift it into neutral.

I also don’t think they’ll have a way to test it.

Unfortunately, I have worked with RK before it isn’t their unwillingness to help. It’s their lack of understanding of how the tractors actually work so diagnostic and repair usually don’t fix the problem.

Thank you for your help.

How would you solve the problem you mentioned above?

 

[oldnslo]

I would find out how to check charge pressure since noise is present even when not moving. Monitor that pressure while operating and see if you notice any change from when noise is present vs not.

 

[JTKub]

Does the noise change when you work any of the hydraulics? Loader controls, steering, 3 point, etc?

It might be worth swapping out the hydraulic filter, if for nothing more than an inspection of the filter internals. Mann, Hummel, Wix, etc, is NOT what they used to be unfortunately.

 

[TORQUIN]

My first thought is that fluid is leaking past a seal inside, and the resonant frequency of the seal flapping, as it tries to maintain the seal, is your noise. I have seen this sort of thing before on a Cummins turbo diesel when the intercooler boots were deteriorated enough that the air would leak past the boots when there was boost happening. When there was boost, there was also a noise like a squealing pig. After a boot change, it was quiet again.
Now, for your situation, I am assuming that your hydraulic system is under pressure someplace when the noise occurs.
The unfortunate part is I don't have additional diagnostic advice for this situation. I have to guess that someone will have to put gauges on test ports of the transmission and readings will need to be taken when the noise occurs and is quiet, then the transmission will have to be taken apart to trace the necessary hydraulic circuit and assess the seals in the circuit.

What kind of fluid did you use? Perhaps a different kind of fluid will change things. If you decide to do this, save your fluid drained in case you want to put it back in.

Chris