B2650 Hydro Noise

[KTuk4J]

I'm experiencing a loud whine, more so after lifting several heavy loads or digging with loader. It starts out quiet.
Fluids/maitenance good. 300 hrs.
From my eperience with any machinery, this is most likey casued by trapped air, however I'm not familiar with these machines.
Is there a releif valve or way to purge the air by bypass?
Thanks in advance.

 

[RCW]

Don’t know the use or service history of your tractor, but I would start with a fluid and filter change before anything else.

My BX has had fluid changes multiple times over the years. Each time it lessens the HST whine.

 

[KTuk4J]

Don’t know the use or service history of your tractor, but I would start with a fluid and filter change before anything else.

My BX has had fluid changes multiple times over the years. Each time it lessens the HST whine.

As metioned, fluids/maintenance good.

 

[Russell King]

As metioned, fluids/maintenance good.

What type of fluid is in it? The synthetic UDT is supposed to help quieten the whine down

 

[North Idaho Wolfman]

There is no way to purge the air out of it.
If it's entraining air into the fluid, you either have contaminated fluid, cheap fluid/wrong fluid, a bad/cheap filter, or damage to the suction side of the system.

 

[RCW]

As metioned, fluids/maintenance good.

I believe the service interval is 400 hours if using SUDT2?

Your fluid has 300 hours on it. Don't know what fluid you are using, or how long it took you to get to 300 hours.

My BX has almost 200 hours on the fluid, and I notice an increase in HST "whine." I may change it out this spring.

Do as you please.

 

[nbryan]

My experience is the whine decreased over the years. 1300hrs on mine, quietest it's been since new.
And every hst fluid and filter change (using Premium UDT here in Canada) it's been quieter.

 

[KTuk4J]

I believe the service interval is 400 hours if using SUDT2?

Your fluid has 300 hours on it. Don't know what fluid you are using, or how long it took you to get to 300 hours.

My BX has almost 200 hours on the fluid, and I notice an increase in HST "whine." I may change it out this spring.

Do as you please.

It's been done and used SUDT2 with change.

 

[KTuk4J]

What I'm gathering so far is, air is NOT the issue where continued fluid change is the remedy?

I wonder why the factory fuid is not sufficiant, taking they used 46HD?

 

[nbryan]

What I'm gathering so far is, air is NOT the issue where continued fluid change is the remedy?

I wonder why the factory fuid is not sufficiant, taking they used 46HD?

Kubota SUDT2 (Premium UDT here in Canada), Kubota filters, maintain according to service schedule.
This is what I do. The whine is still there, but lessened. And it purrs a bit quieter after a fresh change.
The tractor still hauls ass pulling and doing other hydraulics work with that trans and pumps.

 

[KTuk4J]

The fluids have been changed using SUTD2.

The tractor functions great, it just extremely loud when operating the loader.
Can even feel the vibration like fluid is cavitating.

It starts off completely quiet and then gets loud after a few lifts of load.

Sounds like a common problem, however I'm not understanding why it's supposed to bet better after multiple fluid changes?

Could someone explain the reason why that helps?

Never experienced that in all the decades of operating hydraulic machinery.

 

[SDT]

I'm experiencing a loud whine, more so after lifting several heavy loads or digging with loader. It starts out quiet.
Fluids/maitenance good. 300 hrs.
From my eperience with any machinery, this is most likey casued by trapped air, however I'm not familiar with these machines.
Is there a releif valve or way to purge the air by bypass?
Thanks in advance.

B2650 and similar models are well known for hydro whine.

Of course, heavy use will result in increased whine.

Using low range for FEL use?

 

[Russell King]

The fluids have been changed using SUTD2.

The tractor functions great, it just extremely loud when operating the loader.
Can even feel the vibration like fluid is cavitating.

It starts off completely quiet and then gets loud after a few lifts of load.

Sounds like a common problem, however I'm not understanding why it's supposed to bet better after multiple fluid changes?

The loud whine that I recall complaints about is from the hydrostatic transmission when under load. I don’t own or operate a hydrostatic transmission tractor so have no experience with one.

You are stating that it is a load from the loader that causes the whine to start. Is that correct?

If that is the case can you explain what happens if the loader is removed from the tractor and the tractor is used up a steep slope or pulling a heavy load? Does it whine or stay quiet?

From your statement, what is vibrating like fluid is cavitation? I am suspicious that you have something restricting flow in the loader circuit but have no idea where the pump for the hydraulics is or if it is part of the hydrostatic circuit. And unfortunately I am too lazy to look it up today!

 

[KTuk4J]

The loud whine that I recall complaints about is from the hydrostatic transmission when under load. I don’t own or operate a hydrostatic transmission tractor so have no experience with one.

You are stating that it is a load from the loader that causes the whine to start. Is that correct?

If that is the case can you explain what happens if the loader is removed from the tractor and the tractor is used up a steep slope or pulling a heavy load? Does it whine or stay quiet?

From your statement, what is vibrating like fluid is cavitation? I am suspicious that you have something restricting flow in the loader circuit but have no idea where the pump for the hydraulics is or if it is part of the hydrostatic circuit. And unfortunately I am too lazy to look it up today!

It seems to be isolated to the loader. But what's interesting is it can lift heavy loads very quitely for several loads or more then eventually ends up with loud whine/squeal when in use.

I have not noticed it when using a scraper/ripper under load.

 

[Russell King]

That sounds like a much different problem than all of the discussion about what fluid is in it and how that can help.

I would guess that it is something in the hydraulic circuit on the loader, and more specifically that it is in the lines that are the lifting circuit. If I was troubleshooting the problem I would start by making sure any and all quick disconnect are taken apart, cleaned and reseated. You may want to just remove all the disconnects and see if the problem goes away. I would suggest doing that one at a time and start with the line that returns fluid as you lower the FEL.

Does your loader have the regeneration process for faster dumping ( I think that is part of the valve but don’t recall exactly how it works). Does your FEL connect to a block on the tractor (all lines at one time)? (I don’t recall the name of that but has been known to be leaky and otherwise problematic)

I am sure there is a more scientific method of measuring the pressures in the FEL circuit if you want to resolve the issue more easily and efficiently and have the pressure gauge (probably around 3000 PSI to 5000 PSI)

 

[whitetiger]

I wonder why the factory fuid is not sufficiant, taking they used 46HD?

The factory fill was not 46HD, which is a hydraulic fluid, not a trans-hydraulic, it was UDT.
ISO 46 HD is used in construction equipment which is fluid-driven and operated.

 

[nbryan]

Others here know hydraulics and their controls way better than me, but what I'm hearing is:
- the whine occurs when operating the loader, no HST in use
- it only happens once the hydraulics are at operating temperature, i.e. normal working hot.

then my initial focus would be the loader controls, specifically the bypass mechanism.

I get loud HST if in too high a gear under load, like when sometimes I forget I'm still in high gear off a road and start to work with it in H.

But I can't remember the loader complaining like that even hot and lifting at maximum load, so it's mostly bypassing. If the loader can't lift, the bypass just hisses a bit and that's it, no loud whine/squeal like an overloaded HST.

 

[RCW]

Yes, what I’m wondering is if this is not an HST whine at all. Something related to the loader hydraulics.

It comes up sometimes, but there’s the “lift/curl” aspect.

@KTuk4J - do you get the noise when going into a pile, and trying to lift and curl the bucket at the same time?

Transcends many models of Kubota tractors from small to very large.

See how there’s nothing at 7 o’clock position?

According to Kubota the loader won’t work there. I get a pressure relief noise when trying to lift/curl. Usually it’s just a second or two, but it won’t lift or curl and makes some racket.

 

[KTuk4J]

Yes, what I’m wondering is if this is not an HST whine at all. Something related to the loader hydraulics.

It comes up sometimes, but there’s the “lift/curl” aspect.

@KTuk4J - do you get the noise when going into a pile, and trying to lift and curl the bucket at the same time?

Transcends many models of Kubota tractors from small to very large.

View attachment 150486

See how there’s nothing at 7 o’clock position?

According to Kubota the loader won’t work there. I get a pressure relief noise when trying to lift/curl. Usually it’s just a second or two, but it won’t lift or curl and makes some racket.

It's with lift, the heavier the load, more the noise at operating temp.

There a couple of things I need to sort out and try with the loader/connections as mentioned.