M5040 lunges forward when shuttle shifter in neutral, not all the time and it only causes it to rock forward then settle back. If I put the speed control lever ( high/low ) in neutral, this stops. Pushing the clutch in has no effect. This is an intermittent problem and it is hard to duplicate. When it happens, it only last for about minute or so. Any suggestions? Thanks in advance and I have to say I have learned quite a bit from reading this forum over the last 3 years.
M5040 lunges forward when shuttle shift in neutral
- Thread starter RoBoss
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North Idaho Wolfman
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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
In order to give you a more accurate answer to your issue I need to know what exact model you have.
If you don't know get the serial # and give that to me.
If you don't know get the serial # and give that to me.
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I think I know what you're talking about. It's aggravating. Sounds like the old hydraulic shuttle transmission. There is not a dedicated "clutch", the "clutch" pedal is attached to a hydraulic valve that varies the hydraulic flow and pressure to the forward and reverse shuttle clutches. What you are experiencing is some viscous drag. The oil gets in between the clutch plates and causes them to drag a little, kind of halfway engaging. Sometimes it's forward. Sometimes it's reverse. Sometimes it's both, it just rocks back and forth-and seems to be worse in lower gears. Non existent with the main range gear shift in neutral. Is this what you're speaking of? If it is, I am sorry I can't help you. I know what causes it, but I don't know a fix for it. The ones I've seen were worse in cold weather conditions (cold oil is thicker).
That is exactly what I am experiencing. Will it do harm to the tractor if not corrected?
Thanks, the model is: Kubota M5040 DHC, Serial Number: 54044In order to give you a more accurate answer to your issue I need to know what exact model you have.
If you don't know get the serial # and give that to me.
rbargeron
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L5450, L48, L3250, L345 never enough attachments
How many hours on the machine? How has it been used mostly? Does the condition seem oil-temperature-related? If a rear wheel is jacked up, is the lunging more noticeable ? does it grab with shuttle in neutral? (Be careful testing)
The symptoms sound like when a clutch pack's plates become slightly warped. If so replacing the fluid might help some.
If the transmission oil isn't perfectly clear and clean, it should be flushed and replaced, using super UDT and new filters. Super UDT is high end for consistent film strength and performance.
If the clutch stack is getting tighter from disk warpage, getting the oil as clean and consistent as possible should help it perform better.
As always, prompt cheerful refund if advice is bogus. Good luck, Dick B
The symptoms sound like when a clutch pack's plates become slightly warped. If so replacing the fluid might help some.
If the transmission oil isn't perfectly clear and clean, it should be flushed and replaced, using super UDT and new filters. Super UDT is high end for consistent film strength and performance.
If the clutch stack is getting tighter from disk warpage, getting the oil as clean and consistent as possible should help it perform better.
As always, prompt cheerful refund if advice is bogus. Good luck, Dick B
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North Idaho Wolfman
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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
This is why I was asking for a specific model #, what Lugbolt is saying is a know and common issue with that model.
If the issue only effects one direction it could be an adjustment issue.
If the issue only effects one direction it could be an adjustment issue.
rbargeron
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L5450, L48, L3250, L345 never enough attachments
Wet clutches grab (engage) when the piston presses the stack together forcing the oil OUT of the spaces between the disks and slip plates. Oil getting between them causes them to SLIP, not grab.
If the plates and disks are not flat, dragging can result (creeping or pulsing in neutral), even with the pressure removed from the piston. See attached wet clutch pic - the left side has a warped plate and heat damage. (This unit dragged hard - needed new plates)
Dragging is most noticeable in the lowest gears (most gear reduction, most torque). Inconsistency in the fluid makes dragging worse.
The pressure in the forward and reverse clutch stacks should be balanced in neutral. If one side drags, adjusting the oil supply can mask it, and restore apparent balance. But a warped disk will continue to drag until someday replaced.
Warped plates are caused by excess friction heat, most commonly from hard use and contaminated oil. With clean oil and easier use RoBoss's M5040 may remain usable as-is, if not perfect.
If the plates and disks are not flat, dragging can result (creeping or pulsing in neutral), even with the pressure removed from the piston. See attached wet clutch pic - the left side has a warped plate and heat damage. (This unit dragged hard - needed new plates)
Dragging is most noticeable in the lowest gears (most gear reduction, most torque). Inconsistency in the fluid makes dragging worse.
The pressure in the forward and reverse clutch stacks should be balanced in neutral. If one side drags, adjusting the oil supply can mask it, and restore apparent balance. But a warped disk will continue to drag until someday replaced.
Warped plates are caused by excess friction heat, most commonly from hard use and contaminated oil. With clean oil and easier use RoBoss's M5040 may remain usable as-is, if not perfect.
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Thanks, the model is: Kubota M5040 DHC, Serial Number: 54044This is why I was asking for a specific model #, what Lugbolt is saying is a know and common issue with that model.
If the issue only effects one direction it could be an adjustment issue.
I bought this tractor used with about 700 hours on it 2 years ago. I had a Kubota dealer change all fluids and do the 700 hour service this model calls for. It started doing this about a year ago, it has 860 hours on it now. Not worked hard at all. Bushhog about 30 acres with it twice a year, rest of the time use it to maintain half mile lane and a lake. I really have no idea what the tractor was used for before I bought it. The hydraulic fluid look clean and clear to me.
When I worked for the dealer, we knew of the issue. Kubota did not, at the time. Most likely they do now, however, and thus might be worth a call to get more info. I remember some brand new M60's that JUST came out at the time, they did it too..sitting on the transporter not even offloaded to the dealer lot yet. I actually pointed it out to one of the reps and asked him what caused it (said viscous friction). I am not saying that the discs couldn't be warped, but I find it unlikely seeing the few that were literally under an hour old do the same exact thing. Jack up your car's drive wheels (if automatic transmission) and put it in neutral. Start the engine. The wheels will begin to turn once you take your foot off the brake. That is viscous friction causing the internals to turn. The old GM Powerglides were notorious for this; if you didn't have your foot on the brake even in neutral, they'd take off on their own.
Only issues I've ever seen out of the M40's were this issue and sometimes the "clutch pedal" return spring under the tractor would break or get knocked off by sticks, trees, whatever, and then the complaint is that the clutch is "loose feeling" and "grabs". Oh and a PTO clutch or two on the bigger M's-which was preventable. That was IT, good tractors they are. I wouldn't get rid of one for an M60 or M5/M6, but that's just me.
Thanks for taking time to reply. What was the fix for the tractors you knew of, and does it hurt to do nothing. I went to the local dealer and they knew nothing about the problem. They mainly work with the smaller Kubotas, and at first didn't believe Kubota had ever made a M5040. They called the support center and am waiting for a response.
RoBoss, I know the feeling of going to a dealer and they not knowing about the tractor you own.
I had a 5HP gas Kubota lawn mower. I went to the dealer to get a part and the parts man insisted Kubota never made such a mower. I had the owner's manual, and the mower! He called another guy over and they tried their best to make me out as "wrong".
I finally told them, "I'm not a gambling man, but I'll make a bet with you for any amount you fell like losing. Then I'll go out to my truck and bring in the Owner's manual, and you can see who published it."
If I remember correctly, the owner finally came back there to see what the discussion was about!
I had a 5HP gas Kubota lawn mower. I went to the dealer to get a part and the parts man insisted Kubota never made such a mower. I had the owner's manual, and the mower! He called another guy over and they tried their best to make me out as "wrong".
I finally told them, "I'm not a gambling man, but I'll make a bet with you for any amount you fell like losing. Then I'll go out to my truck and bring in the Owner's manual, and you can see who published it."
If I remember correctly, the owner finally came back there to see what the discussion was about!
rbargeron
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L5450, L48, L3250, L345 never enough attachments
Viscous friction is well-understood by anybody pushing a hydraulic-drive machine by hand. But adding oil to sliding metal surfaces generally does not INCREASE drag.
The two situations described in this thread are quite different. The original post was about a machine that had not been "grabby" before but started lurching after many hours of use. Something had changed in the clutch stack making it grab sometimes even when relaxed.
The new machines that act this way likely have different underlying causes. Manufacture and assembly can leave dust and debris that can get into the wet clutch making one side or the other grabby. Most clear up on their own with use, some may need an adjustment of the valving to restore balance. Balance is illusive in twin opposed clutch assemblies - all of the friction forces (including viscous) have to offset each other.
Regarding your M5040, with regular oil and filter changes, its possible the grabbing will not get worse. If something inside the trans is making small metal debris that's getting into the clutches before being caught by the filter, the grabbing could increase. But tearing it down may not show conclusive evidence of the cause. I'd spend the money on oil changes unless/until the grabbing becomes intolerable. The wet clutch in the picture above pulled in neutral all the time. In fairness to the clutch design, it was in a loader/backhoe and had been used hard.
To verify the oil is clean drain a few quarts into a clean white container and let it settle for a while - then pour it out looking for metal dust left behind. Gray discoloration is microscopic worn metal.
It might be worthwhile to check the resting pressure of the hydraulic shuttle. It should be zero, but if it's pulsing for some reason that could cause grabbing too.
The two situations described in this thread are quite different. The original post was about a machine that had not been "grabby" before but started lurching after many hours of use. Something had changed in the clutch stack making it grab sometimes even when relaxed.
The new machines that act this way likely have different underlying causes. Manufacture and assembly can leave dust and debris that can get into the wet clutch making one side or the other grabby. Most clear up on their own with use, some may need an adjustment of the valving to restore balance. Balance is illusive in twin opposed clutch assemblies - all of the friction forces (including viscous) have to offset each other.
Regarding your M5040, with regular oil and filter changes, its possible the grabbing will not get worse. If something inside the trans is making small metal debris that's getting into the clutches before being caught by the filter, the grabbing could increase. But tearing it down may not show conclusive evidence of the cause. I'd spend the money on oil changes unless/until the grabbing becomes intolerable. The wet clutch in the picture above pulled in neutral all the time. In fairness to the clutch design, it was in a loader/backhoe and had been used hard.
To verify the oil is clean drain a few quarts into a clean white container and let it settle for a while - then pour it out looking for metal dust left behind. Gray discoloration is microscopic worn metal.
It might be worthwhile to check the resting pressure of the hydraulic shuttle. It should be zero, but if it's pulsing for some reason that could cause grabbing too.
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Thanks everyone for your input, I will check fluid and filters. If it doesn't get worse, I will just live with it.