HST "whine" getting louder L3301

random

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It's a bit overdue for maintenance (I'll be doing it in the next couple weeks) so I have a couple suspicions, but I'm wondering what you guys might think is going on. Best way I can describe it is that the normal HST "whine" recently is louder than I'm used to and it sounds like it's struggling more than usual. Noticed this only the last couple times I've used it, which, incidentally, has been after hooking the backhoe back up.

This suggest anything to anyone?
 

je1279

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It's a bit overdue for maintenance (I'll be doing it in the next couple weeks) so I have a couple suspicions, but I'm wondering what you guys might think is going on. Best way I can describe it is that the normal HST "whine" recently is louder than I'm used to and it sounds like it's struggling more than usual. Noticed this only the last couple times I've used it, which, incidentally, has been after hooking the backhoe back up.

This suggest anything to anyone?
Hydraulic fluid degrades over time with use which can result in more whine and decreased performance. I would complete the required maintenance and use both Kubota filters and SUDT2 hydraulic fluid. If that quiets it back down, I'd expect that you would be good to go.
 
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ayak

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Are you seeing any difference whether you’re in Low/Medium/High with what you’re doing? Mine squeals like a big pig when I’m doing certain things in too ‘high’ a range (lugging my backhoe up a long hill).
 

random

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I usually run in Medium and that's the current case too - so the sound change is from Medium to Medium, with similar activities. I've definitely noticed more "stress" when changing to High.
 

ayak

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I usually run in Medium and that's the current case too - so the sound change is from Medium to Medium, with similar activities. I've definitely noticed more "stress" when changing to High.
Got it—just a thought. Also, with my BH coming on and off all the time, I keep a pretty close eye on my fluid level as I’m always losing a little with the changeovers—that in and of itself makes mine a little more whiny if it’s running lower.
 

random

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so a couple ideas so far, matching up with my thoughts: I'm mainly thinking that the fluid is probably a bit low and that things should go back to normal after I do the service. I can easily see how low fluid would cause the entire system to strain more.
 

SDT

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It's a bit overdue for maintenance (I'll be doing it in the next couple weeks) so I have a couple suspicions, but I'm wondering what you guys might think is going on. Best way I can describe it is that the normal HST "whine" recently is louder than I'm used to and it sounds like it's struggling more than usual. Noticed this only the last couple times I've used it, which, incidentally, has been after hooking the backhoe back up.

This suggest anything to anyone?
It's significantly heavier now that the BH is on.

Accordingly, "it's struggling more" and the whine has increased.

SDT
 

85Hokie

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S-UDT2 and the whine will be less noticeable
 

dirtydeed

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It's significantly heavier now that the BH is on.

Accordingly, "it's struggling more" and the whine has increased.

SDT
X2. Good call.
 

RCW

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Yes, the weight of the BH.

The often-debated first fluid change will make a difference.

I’ve changed my fluid 3 times in 8 years/425 hours. Makes an improvement each time.
 
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OlFerguson

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Sure , the fluid change is all great and dandy , but where is this whine coming from ? I feel like a valve somewhere in the hst is leaking or something is not functioning the way it should
 

je1279

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I guess my suggestion was to do the maintenance to rule out the fluid or the fluid level being the issue. I'm also assuming that the noise is louder with the backhoe on currently than it was with the backhoe on previously (both in mid range as @random stated). If the whine is still louder than normal after the maintenance, I agree that additional troubleshooting is required.
 

ayak

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Sure , the fluid change is all great and dandy , but where is this whine coming from ? I feel like a valve somewhere in the hst is leaking or something is not functioning the way it should
Some degree of whine is actually considered normal with these models. Certainly a big change not attributable to fluid level and quality should be investigated, but doesn’t seem warranted in this instance.
 
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random

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Nov 2, 2020
717
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I'm also assuming that the noise is louder with the backhoe on currently than it was with the backhoe on previously (both in mid range as @random stated).
Yes, I'm comparing current time with the BH vs last time with it - I don't remember it sounding like it was struggling before. I wish I could describe it better than that...
 
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random

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717
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Some degree of whine is actually considered normal with these models. Certainly a big change not attributable to fluid level and quality should be investigated, but doesn’t seem warranted in this instance.
When I first joined here, someone had posted a video of their HST tractor "whine" and everyone said it was normal, sounded just like mine. I've had it for 5 years (but haven't put a lot of hours on it - I don't use it as much as you guys do!) and this is the first time I've heard it sound like this.

Just wanted to confirm my thoughts - seems like just doing the maintenance is a good start (as I suspected)
 

aaluck

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S-UDT2 and the whine will be less noticeable
I recently had mine changed. Not sure what was in there as I purchased my L4400 used 550 hours so I'm assuming;) it had been changed before. Unfortunately the dealer used the regular UDT, which is what the manual calls for, but I have noticed it's a bit louder of a whine. I wish they would have used the SUDT, which the manual also calls for. Maybe would have been a bit quieter.
 
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minthral

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The whine comes from a hydraulic fluid pump and resonates through transmission metal and ROPS (or cab) act kind of like a speaker to amplify it. The L series is intended to be 'simple machines without bells and whistles' and that's actually a reason many people buy them. However this means Kubota didn't add extra fancy stuff to quiet them down (unlike grand L tractors).

I personally DONT like the whine as it's high pitch and makes it past my noise canceling earbuds easy. There is an upside though...the noise lets you hear what strain the tractor is under and basically teaches you to run high RPMs mostly.

If you're getting 'increasing whine' it's because the tractor is under more load (has more weight on it) or something like brakes are dragging. Or you're running lower RPMs than before. Or it's colder outside. Some people said they get more whine by having low fluid level... I kinda doubt it, though maybe this would let sound resonate more since there is less mass in the body.

Regarding 'change the fluid to super UDT2' statements. It doesn't help and actually makes it worse. At 50 hrs, I changed all fluids and filters. On many Kubota models, this is the default maintenance, however on L series they say you can wait till 200 hrs to change it (along other fluids). There is like 7 gallons of expensive hydraulic oil to replace and the fluid looked fine honestly... felt I just wasted time/money replacing it at 50. There were some metal shavings on the filter magnets.

What I find is the tractor with new fluid has considerable MORE whine. Operating at low RPMs and cold temps make it worse.

The whine reduces after about 50 hours of decent usage to 'break in' after fluid change. Once the fluid warms up, it is noticeably less whiny. I always operate the tractor between PTO RPM and WOT. I'd say 95% of the time, I'm at WOT. There is a noticeable difference when its warm or hot outside... the whine is less. Worst situation for whine: freezing temps out, just started up, backhoe/loader is on, 4WD engaged, and going up hill in M gear. Try same thing when it's nice out, no loader/backhoe, flat land, L gear, 2WD, and then it's quiet.

Here is a tip: What I discovered is if you run it a tick under WOT, the overall noise from the tractor (including motor and pump whine) is less, but power isn't too much less. You can play with the RPMs to find different frequencies the whine will resonate at.

All HST equipment whines to some extent, but the higher end stuff less so. My 2 cents is the L series is a nice tractor at a nice price, but it's not in the 'high end' category. Thus if you want a quiet tractor, you're going to trade grand L. I don't think the BX, B, or LX is any less whiney. MX not sure.
 

jyoutz

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Jan 14, 2019
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Edgewood, New Mexico
The whine comes from a hydraulic fluid pump and resonates through transmission metal and ROPS (or cab) act kind of like a speaker to amplify it. The L series is intended to be 'simple machines without bells and whistles' and that's actually a reason many people buy them. However this means Kubota didn't add extra fancy stuff to quiet them down (unlike grand L tractors).

I personally DONT like the whine as it's high pitch and makes it past my noise canceling earbuds easy. There is an upside though...the noise lets you hear what strain the tractor is under and basically teaches you to run high RPMs mostly.

If you're getting 'increasing whine' it's because the tractor is under more load (has more weight on it) or something like brakes are dragging. Or you're running lower RPMs than before. Or it's colder outside. Some people said they get more whine by having low fluid level... I kinda doubt it, though maybe this would let sound resonate more since there is less mass in the body.

Regarding 'change the fluid to super UDT2' statements. It doesn't help and actually makes it worse. At 50 hrs, I changed all fluids and filters. On many Kubota models, this is the default maintenance, however on L series they say you can wait till 200 hrs to change it (along other fluids). There is like 7 gallons of expensive hydraulic oil to replace and the fluid looked fine honestly... felt I just wasted time/money replacing it at 50. There were some metal shavings on the filter magnets.

What I find is the tractor with new fluid has considerable MORE whine. Operating at low RPMs and cold temps make it worse.

The whine reduces after about 50 hours of decent usage to 'break in' after fluid change. Once the fluid warms up, it is noticeably less whiny. I always operate the tractor between PTO RPM and WOT. I'd say 95% of the time, I'm at WOT. There is a noticeable difference when its warm or hot outside... the whine is less. Worst situation for whine: freezing temps out, just started up, backhoe/loader is on, 4WD engaged, and going up hill in M gear. Try same thing when it's nice out, no loader/backhoe, flat land, L gear, 2WD, and then it's quiet.

Here is a tip: What I discovered is if you run it a tick under WOT, the overall noise from the tractor (including motor and pump whine) is less, but power isn't too much less. You can play with the RPMs to find different frequencies the whine will resonate at.

All HST equipment whines to some extent, but the higher end stuff less so. My 2 cents is the L series is a nice tractor at a nice price, but it's not in the 'high end' category. Thus if you want a quiet tractor, you're going to trade grand L. I don't think the BX, B, or LX is any less whiney. MX not sure.
I don’t have anything to compare it to. My MX is my first hydrostatic tractor. But I don’t notice a very significant whine with my tractor except at low RPMs in cold weather.
 

Cranblue

Member
Feb 23, 2019
64
13
8
Lincolnton NC
The whine comes from a hydraulic fluid pump and resonates through transmission metal and ROPS (or cab) act kind of like a speaker to amplify it. The L series is intended to be 'simple machines without bells and whistles' and that's actually a reason many people buy them. However this means Kubota didn't add extra fancy stuff to quiet them down (unlike grand L tractors).

I personally DONT like the whine as it's high pitch and makes it past my noise canceling earbuds easy. There is an upside though...the noise lets you hear what strain the tractor is under and basically teaches you to run high RPMs mostly.

If you're getting 'increasing whine' it's because the tractor is under more load (has more weight on it) or something like brakes are dragging. Or you're running lower RPMs than before. Or it's colder outside. Some people said they get more whine by having low fluid level... I kinda doubt it, though maybe this would let sound resonate more since there is less mass in the body.

Regarding 'change the fluid to super UDT2' statements. It doesn't help and actually makes it worse. At 50 hrs, I changed all fluids and filters. On many Kubota models, this is the default maintenance, however on L series they say you can wait till 200 hrs to change it (along other fluids). There is like 7 gallons of expensive hydraulic oil to replace and the fluid looked fine honestly... felt I just wasted time/money replacing it at 50. There were some metal shavings on the filter magnets.

What I find is the tractor with new fluid has considerable MORE whine. Operating at low RPMs and cold temps make it worse.

The whine reduces after about 50 hours of decent usage to 'break in' after fluid change. Once the fluid warms up, it is noticeably less whiny. I always operate the tractor between PTO RPM and WOT. I'd say 95% of the time, I'm at WOT. There is a noticeable difference when its warm or hot outside... the whine is less. Worst situation for whine: freezing temps out, just started up, backhoe/loader is on, 4WD engaged, and going up hill in M gear. Try same thing when it's nice out, no loader/backhoe, flat land, L gear, 2WD, and then it's quiet.

Here is a tip: What I discovered is if you run it a tick under WOT, the overall noise from the tractor (including motor and pump whine) is less, but power isn't too much less. You can play with the RPMs to find different frequencies the whine will resonate at.

All HST equipment whines to some extent, but the higher end stuff less so. My 2 cents is the L series is a nice tractor at a nice price, but it's not in the 'high end' category. Thus if you want a quiet tractor, you're going to trade grand L. I don't think the BX, B, or LX is any less whiney. MX not sure.
My L4701 fluid change for hydraulic is 400hrs same as motor oil !!! Blows my mind that motor oil is same change interval as Super UDT 2 . I ran heavy equipment for a living had JD excavator hydro fluid was 4K hours for change !!!
 

AdmiralS

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ToolCat UW53 (On Order), LX3310HSDC
Dec 7, 2021
15
12
3
Hudson Valley, New York
My LX3310 Cab had a significant whine. I changed the HST fluid at the 50 hour service (happy I did as a significant amount of wear in metals came out).

There was a noticeable reduction in whine after that fluid change. There is still a whine but I was having to wear hearing protection previously to deal with it and that is no longer the case.