Kubota M4 Utility Tractor Transmission Whine

[Bush Whacker]

So was playing with it today. Anyone else able to go run their tractor parked with the break and engage/disengage the 4WD a few times and see what happens?

Mine doesn’t lurch forward but it absolutely moves. I find that pretty disturbing. I would understand if it moved when I engaged because it pressurized the system I guess but disengagement as well? Something ain’t right, I’m about to see what it takes to get some official paper on this.

I have not tried that. Tractor is in remote location for me so will test that and report back later.

 

[Jigawatts]

Update: Just got off the phone with a Kubota dealer in the Ottawa region. They have confirmed that Kubota is well aware of the issue and it is related to a pressure relief valve. Even after replacing it with a new one, the issue came back after a few hours. Good news is that they are working on it. I was advise to continue to use the machine as, other then it being annoying, it will not impact functionality.

So I have a new M4-071 HDC and have had the same issues being described here since day one. My tractor is in a remote area, so I sent a video of noise to dealer and they don’t seem concerned? (Like others have said probably don’t have an answer) I have been looking for information since last year on this subject and am so glad you folks are putting some together here! Love the tractor so far, 48 hrs; however and definitely suspicious of what this noise and more importantly the extremely hot transmission fluid which is being created by the same problem causing noise….. is going to do to the tractor down the road. As you said it doesn’t impact functionality “for now”. The transmission fluid temps being as hot as they are, absolutely will degrade the trans fluid and of course that will inevitably lead to some kind of other premature failure. Anxiously awaiting news of a PSB or fix!

 

[rScotty]

Does this sound familiar? I think it was in an operator's manual where I came across a recommendation to hold the steering wheel all the way to lock for a few seconds as a way to heat up the hydraulic fluid on real cold mornings.
I've never tried it, but wonder if anyone else had heard of that.

And here's a site on oddball hydraulic troubleshooting. Makes for some interesting reading.

Insane Hydraulics Blog Home Page

InsaneHydraulics.com welcomes you! This is The meeting place for SMART oil hydraulics related people.

www.insanehydraulics.com

rScotty

 

[Jigawatts]

So I have less than 20 hours on my new M4D and yes it makes the same whine while hot and in 4WD or when the brakes are touched. Initially I thought it was a loose belt as it comes from up front near the radiator. I think it's a bypass valve that is kicking on and allowing hydraulic fluid to pass. I have no issue when cool or even if I engage then turn off the 4WD switch it will go away. I did at first have a belt squeal when first starting but I tightened the alternator a touch and that went away.

Certainly has to be warm. I noticed it while I was running a bat wing mower and working the unit fairly hard. After about 20 minutes I slowed down and stopped to move some debris in front of me when I noticed it and seems to corellate with the 4WD button and the brakes. I believe the front wheels are engaged into 4WD while the brakes are engaged to safely slow down and maneuver. That would imply it's the engagement of the 4WD system that is causing this issue.

I would have to agree on the bypass valve idea. To me, mine sounds like a valve going into relief? Albeit a loud relief. I also had the dealer add a third remote valve on my rear remotes and when the tractor is making that noise that top(third) valve body is definitely super hot…can’t leave your finger on it at all, and the valve feels like the source(kind of vibrating if you will)? There is also what appears to be a protruding bypass valve looking item right in front of those rear remote valves and it vibrates there too?

maybe sea2summit can shed some light on that?

 

[sea2summit]

I would have to agree on the bypass valve idea. To me, mine sounds like a valve going into relief? Albeit a loud relief. I also had the dealer add a third remote valve on my rear remotes and when the tractor is making that noise that top(third) valve body is definitely super hot…can’t leave your finger on it at all, and the valve feels like the source(kind of vibrating if you will)? There is also what appears to be a protruding bypass valve looking item right in front of those rear remote valves and it vibrates there too?

maybe sea2summit can shed some light on that?

That seems odd, what type of valve? Self canceling? I thought they stacked so wouldn’t that be flowing past all of them? I’ll pull the manual out tomorrow and see what it shows.

 

[Jigawatts]

That seems odd, what type of valve? Self canceling? I thought they stacked so wouldn’t that be flowing past all of them? I’ll pull the manual out tomorrow and see what it shows.

Yes on the self canceling and yes they are stacked, I was thinking the feeling could be transferring from close by but the top valve on the stack is the one that is feeling like it is different from the others. Stronger vibration like fluid passing through at all times but, just not sure about it? There is also what looks like a relief of some sort on the top of trans immediately in front of that stack that feels the same?

 

[sixdogs]

Let me toss this out as an FYI because I do not know beans about the M4 whine. I did, however, have similar strange issues and related on a 5520 Deere that stumped me and the dealer.

In short it turned out that the remote levers valves sticking ever so slightly from not being used and we discovered this by accident even when the dealer couldn't find anything. I just worked the levers a little back and forth and the overheating of the trans fluid stopped. Other functions back to normal. In talking with others later, I learned that remote valve levers get sticky if you don't move them a little every now and then and can cause problems. The dealer spent $500+ (10 years ago) looking for the problem

This probably isn't your issue but you never know. Just my two cents.

 

[Jigawatts]

Let me toss this out as an FYI because I do not know beans about the M4 whine. I did, however, have similar strange issues and related on a 5520 Deere that stumped me and the dealer.

In short it turned out that the remote levers valves sticking ever so slightly from not being used and we discovered this by accident even when the dealer couldn't find anything. I just worked the levers a little back and forth and the overheating of the trans fluid stopped. Other functions back to normal. In talking with others later, I learned that remote valve levers get sticky if you don't move them a little every now and then and can cause problems. The dealer spent $500+ (10 years ago) looking for the problem

This probably isn't your issue but you never know. Just my two cents.

Good info! I’m here for the two cents! I have tried moving the levers before thinking the same thing as the tractor does sit for a month or two between uses; however, no joy. When I test drove the tractor(cold trans fluid and only two valves no noises, but since it was dropped off I have had all sorts of noises and whining that comes and goes but mostly always there) Also, I have the same noises mentioned above with the brakes and four wheel drive engagement. I have seen a couple videos online where the owner states that after 100-200 hours the noise stops?

 

[rScotty]

Taking it from another viewpoint,.. What are the things that could cause a relief valve to open?

Too much pressure, relief spring set too low, restriction in the relief opening, restriction in the return line.... Surely there are more, but those are the easy ones. Now I wonder which ones are also more likely to happen after the fluid is warmed up? Something binding in the relief valve maybe - but that doesn't explain why the relief valve is triggered to begin with.

All in ll, I don't think it would be system over-pressure or the relief spring setting. Those are both too easy to measure & would have been found out right away with basic pressure tests.

Which just leaves us looking for restrictions. And especially for a restriction that is triggered by heated oil.

And for something not simple. The people who are working on it sound motivated and have already checked the simple stuff. It sounds interesting enough to make me wish I was involved in the troubleshooting.
rScotty

 

[sea2summit]

I would have to agree on the bypass valve idea. To me, mine sounds like a valve going into relief? Albeit a loud relief. I also had the dealer add a third remote valve on my rear remotes and when the tractor is making that noise that top(third) valve body is definitely super hot…can’t leave your finger on it at all, and the valve feels like the source(kind of vibrating if you will)? There is also what appears to be a protruding bypass valve looking item right in front of those rear remote valves and it vibrates there too?

maybe sea2summit can shed some light on that?

Had mine running for a little over an hour doing chores this evening and didn’t use the remotes so figured I’d see how mine felt. Does yours have the same block on top?

I’m pretty sure that’s what allows the flow to transit from one side down the other. It wasn’t too hot to touch but was unpleasantly warm. The top valve wasn’t hot but was warmer than the bottom which felt only slightly warmer than anything else back there. I think that’s just normal operation. I know when I use the remotes and need to swap implements/hoses they are warm enough I wear gloves for more than just protection against hydro pressure leaks. I didn’t feel anything that seemed to be moving/vibrating but it’s on a running tractor so not the easiest thing to feel for.