2010 Kubota B26 TLB, noisy hydro

Overtaxed · Aug 18, 2018

Went to look at a B26 for sale today, very nice little machine! Really impressed with the digging, it's not a 3 ton mini-ex, but it digs way beyond it's weight class!

Anyway, one thing gave my pause, the hydro was really noisy on it compared to my Kioti NX6010 (the only other hydro tractor I've ever driven except for a ZTM). I asked the seller about it and he said it's always sounded like that, and it seemed to operate fine, hydro fluid looked and smelled good, it was just noisy. When you hit the petal from R to F you where a "moan" as it started to push, and then a constant moan as you drove along. It sounded (but didn't feel) like it was "lugging" the hydro, if that makes any sense.

Any owners here feel the same about their B26? Am I just not used to it? Or could it indicate something wrong with the hydro system (which is a no-go for me, lord know what that might cost to repair!). Nothing else in the hydro system seemed to indicate anything but "fine"; loader lifted the front end of the tractor right up, BH was strong, fast and dug easily, stabilizers lifted the tractor to full height. Just the drive motor had a noise.

Actually, I did think of something I can compare it to. When I turn the wheel on my Kioti to full lock and hold it there, it makes a similar sound. A "moan" in the hydro system, that's the best way I can describe it.

powerstroke444e · Aug 18, 2018

I have forgotten my parking brake and it makes the hydro grown a little but not overly noise. But will say it makes no more noise than any other hydro tractor.

bkrgi · Aug 20, 2018

You can hear the Hydro whine in my vid over the engine and flail (is a 2016 B26 in mid range) for comparison..maybe
Woodmaxx FM62H - YouTube

Fallon · Aug 20, 2018

Kubota SUDT2 fluid quiets things down a bit compared to other hydraulic fluids. HSTs are always a bit noisy compared to other transmission types. The smaller & less mass in the transmission housing the noisier. The extra mass on the bigger machines dampens the noise a bit.

As a side note. The HST system doesnt run tractor hydraulics. That is a separate pump. They share a common sump & fluid, but are otherwise unrelated.

100 td · Aug 20, 2018

Something to consider, and very dependent on seller...........
You may or may not be able to extensively test this machine. If you can, get the machine nice and hot, transmission/hydraulics up to operating temperature, select low and 4wd, push into a pile of dirt and ensure you can spin the wheels when hot, and also see how much noise it makes. Noise is a very hard one to judge when you don't have another to compare it to. If you are really keen to buy the machine, and after you buy it you find the HST is poor, it will cost you a LOT of $$ to repair.

You could offer to replace the oil and filters on the machine. Use SUDT2, and try the machine out then. Yes it's a big cost, but if you buy the machine and it has HST problems, you'll have a huge amount of money going down the drain. If the seller agrees to allow you/he to do this, you never know, he may even come to half way on the cost if he hasn't recently changed the oil (and you don't buy it). This way, you change fluids, test machine, you either loose some money and not buy the machine, or you buy the machine, and you have already done the oil and fluid change you would have done on it when you first got it home.
Very dependent on seller, your abilities, not for everyone, but there's no harm in asking, perhaps? YMMV.

CurtisC · Aug 20, 2018

Fallon said:
Kubota SUDT2 fluid quiets things down a bit compared to other hydraulic fluids. HSTs are always a bit noisy compared to other transmission types. The smaller & less mass in the transmission housing the noisier. The extra mass on the bigger machines dampens the noise a bit.

As a side note. The HST system doesnt run tractor hydraulics. That is a separate pump. They share a common sump & fluid, but are otherwise unrelated.

As stated hydrostatic tranny's are noisy by their nature and one way to make a Kubota HST noisier is to run anything other than Kubota's SUDT2 oil, another (from personal experience) is to use other than Kubota hydraulic and HST filters. If you slide under the tractor you can see the hydraulic filter mounted on right side of reservoir and HST filter on the left side of the transmission. Cavitation in the pump caused by too much supply line restriction (WIX hydraulic filter in my case) or air entering the line (possibly cracked rubber supply line elbow at the pump or a crack in metal supply line) can cause a noisy pump. If you suspect the wrong oil has been used, particularly if someone put standard hydraulic oil in thinking it was OK (also happened to me when I bought my B26 used) you'll need to dump the oil and run a load of the good stuff until warm (I used UDT which is synthetic but cheaper) dump that and then put in SUDT2. My experience is the "whine" is more pronounced when you first start it up so make sure to listen to it after the system's warmed up. Obviously this is not as noticeable on a warm summer day as a cold winter morning.

One point of clarification the B26 only has one 2 stage hydraulic pump. The main stage handles everything but power steering which connected to second port or stage.

rScotty · Aug 20, 2018

Overtaxed said:
Went to look at a B26 for sale today, very nice little machine! Really impressed with the digging, it's not a 3 ton mini-ex, but it digs way beyond it's weight class!

Anyway, one thing gave my pause, the hydro was really noisy on it compared to my Kioti NX6010 (the only other hydro tractor I've ever driven except for a ZTM). I asked the seller about it and he said it's always sounded like that, and it seemed to operate fine, hydro fluid looked and smelled good, it was just noisy. When you hit the petal from R to F you where a "moan" as it started to push, and then a constant moan as you drove along. It sounded (but didn't feel) like it was "lugging" the hydro, if that makes any sense.

Any owners here feel the same about their B26? Am I just not used to it? Or could it indicate something wrong with the hydro system (which is a no-go for me, lord know what that might cost to repair!). Nothing else in the hydro system seemed to indicate anything but "fine"; loader lifted the front end of the tractor right up, BH was strong, fast and dug easily, stabilizers lifted the tractor to full height. Just the drive motor had a noise.

Actually, I did think of something I can compare it to. When I turn the wheel on my Kioti to full lock and hold it there, it makes a similar sound. A "moan" in the hydro system, that's the best way I can describe it.

A lot of HSTs do make a noise like that - does it get quieter when you downshift? Reason I ask is that I can - anyone can - make any HST really moan if I ask it to do too much while it's in too high of a gear and especially on a slight uphill. For those conditions then, a lot of moaning and complaining is normal. But you ought to be able to get down to a low enough gear so that it can handle the load with only a little HST whine....not the kind of groaning moan that you get when turning the power steering against the stops.

At least that's the test I use....I ask myself, "does the HST noise get a lot quieter when the load and the gear are well matched? If so, it's probably OK."
Everyone has their own sensitivity to that **** HST noise.

rScotty