edsan said:
From what you say, my experience is that the HST pump, and probably the motor are worn or damaged. There is a possibility of air in the oil. Try running it until the problem happens, then remove the HST filter, see if the oil is foamy.
Tractor squeals under load after getting warm
- Thread starter hlukeh
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From what you say, my experience is that the HST pump, and probably the motor are worn or damaged. There is a possibility of air in the oil. Try running it until the problem happens, then remove the HST filter, see if the oil is foamy.
Hi Edsan,
Sorry I never replied to you. I've been really busy lately and haven't been thinking about this. I have not gotten my tractor fixed yet, have you?
Through the winter the tractor was fine since it was cold out, and I am now starting to notice the problem again. I got a pfd of the service manual as was suggested on this forum a few months ago, and after looking through it I realized that I hadn't changed the hydraulic fluid initially. Today I replaced both hydraulic filters - the HST filter and the hydraulic filter, and drained the hydraulic fluid (~22L) from two separate drain ports. The fluid was extremely dirty - black and even silvery with metal particles. I've never seen such terrible oil of any sort - not even our lawn mower that has never had the oil changed.
After replacing the fluid I drove around our pasture in low range for about an hour dragging the blade and the tractor seemed fine. Then when I drove back up the very steep hill to the house the tractor would only make it half way up and then started whining as soon as I pressed the pedal. The tractor whines just as bad when I try to back up the hill. It's like it thinks it's in high range. I even tried taking it out of 4WD but it still just whines.
The hydraulic cooler is quite beat up. I'm not sure why because it's inside the front hood. I'm not sure if that could affect it. The cooler itself felt quite cool, but the hydraulic filters felt pretty hot but not too hot to touch.
I'm so sad, it cost $180 for the New Holland filters and the oil and I totally thought it was going to fix the problem because the old fluid was so, so bad...
Let me know if you have any suggestions.
Thanks,
Luke
Sorry I never replied to you. I've been really busy lately and haven't been thinking about this. I have not gotten my tractor fixed yet, have you?
Through the winter the tractor was fine since it was cold out, and I am now starting to notice the problem again. I got a pfd of the service manual as was suggested on this forum a few months ago, and after looking through it I realized that I hadn't changed the hydraulic fluid initially. Today I replaced both hydraulic filters - the HST filter and the hydraulic filter, and drained the hydraulic fluid (~22L) from two separate drain ports. The fluid was extremely dirty - black and even silvery with metal particles. I've never seen such terrible oil of any sort - not even our lawn mower that has never had the oil changed.
After replacing the fluid I drove around our pasture in low range for about an hour dragging the blade and the tractor seemed fine. Then when I drove back up the very steep hill to the house the tractor would only make it half way up and then started whining as soon as I pressed the pedal. The tractor whines just as bad when I try to back up the hill. It's like it thinks it's in high range. I even tried taking it out of 4WD but it still just whines.
The hydraulic cooler is quite beat up. I'm not sure why because it's inside the front hood. I'm not sure if that could affect it. The cooler itself felt quite cool, but the hydraulic filters felt pretty hot but not too hot to touch.
I'm so sad, it cost $180 for the New Holland filters and the oil and I totally thought it was going to fix the problem because the old fluid was so, so bad...
Let me know if you have any suggestions.
Thanks,
Luke
Here are some pictures of the hydraulic fluid that came out, as well as the cooler.
Does anyone have any idea if an automotive cooler would be fine to replace this one with, assuming the inlet and outlet sizes were the same? I think replacing the cooler may be a good next step, although I know that just replacing parts isn't going to fix the problem - unless of course the problem part is replaced...
Does anyone have any idea if an automotive cooler would be fine to replace this one with, assuming the inlet and outlet sizes were the same? I think replacing the cooler may be a good next step, although I know that just replacing parts isn't going to fix the problem - unless of course the problem part is replaced...
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jinman
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hlukeh said:
I think your HST is self-destructing and the whine you are hearing is excessive pump or motor bypass. The looks of your fluid plus the silver particles are telling me that something is coming apart. The dark fluid is an indication of excessive heat and the particles are indications of wear. Either of those is a bad omen. Both is a sure bet that your transmission is going quickly.
I don't think I would replace that HST cooler right away. I'd first remove it and see if it was clear and allowing fluid to pass. If it is plugged up, that could be the reason your oil overheated and started the downhill progress. Also, make sure your filter mount is clear and not plugged either.
I hate to say it, but I think it is time for a transmission rebuild before it goes away completely and has to be replaced. Right now your tractor is moving on flat ground, but soon you may get stuck in the field with it because it refuses to move. I just don't think this is a simple fix from the looks of your oil and all the other symptoms.
Philmorley1
New member
Hi,
I am not an expert but have had some similar symptoms with my kubota. are you going up the hill in the H gear range? if so that may be just too much load for the tractor in that range.
Phil
I am not an expert but have had some similar symptoms with my kubota. are you going up the hill in the H gear range? if so that may be just too much load for the tractor in that range.
Phil
Haha! Phil, if I could drive anywhere except on a very flat road in high range, I would be so excited! I pretty much only drive the tractor around in Low range because it usually squeals if there is any load on the tractor in medium or high range.
Jim, you're probably right about the rebuild, but I bet my grandfather never changed the oil, so maybe the color and slight metal buildup is normal after 20+ years of light usage.
I still have a feeling that the issue has to do with a specific part since it is definitely affected when the engine warms up. I'll probably take off the cooler, see if I can blow air through the fins and see how well fluid flows through the chamber. It's somewhat suspect to me considering that the hydraulic piping, filters, etc were hot (maybe 122F) whereas the cooler wasn't even warm. To me the cooler should be hotter than the other parts since it should be dissipating heat.
You mentioned checking the filter mount for buildup. You mean where the filter screws onto the tractor? I forgot to mention that when I took off the hydraulic filter there were flakes of what looked like filter material blocking the ports which is not a good sign, and would have definitely been affecting the flow.
Thanks again for all the help you've given me!
Luke
Jim, you're probably right about the rebuild, but I bet my grandfather never changed the oil, so maybe the color and slight metal buildup is normal after 20+ years of light usage.
I still have a feeling that the issue has to do with a specific part since it is definitely affected when the engine warms up. I'll probably take off the cooler, see if I can blow air through the fins and see how well fluid flows through the chamber. It's somewhat suspect to me considering that the hydraulic piping, filters, etc were hot (maybe 122F) whereas the cooler wasn't even warm. To me the cooler should be hotter than the other parts since it should be dissipating heat.
You mentioned checking the filter mount for buildup. You mean where the filter screws onto the tractor? I forgot to mention that when I took off the hydraulic filter there were flakes of what looked like filter material blocking the ports which is not a good sign, and would have definitely been affecting the flow.
Thanks again for all the help you've given me!
Luke
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jinman
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Luke, I was speaking of the pressure bypass checkvalve that is normally installed in the HST filter mount. If that bypass is stuck open, you may not be sending any fluid to the cooler. I would disconnect everything, clean it and test by blowing low pressure air through it.
...and by the way. If your grandfather never changed the oil, in 20+ years, there's a good chance that the HST is completely worn out. Cool fluid would give some power, but when the fluid gets hot (maybe very hot internally) it thins out and bypasses worn pump cylinders. I don't think you will find a simple solution to your problem. It could be a pressure relief valve stuck partially open, but until you get it out and check it, you'll never know.
Coyote machine
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If it were my tractor I would take the cooler to a radiator repair shop to dip it and pressure and flow test it. After verifying it was good enough to reuse then I would do what has been suggested to your probably failed HST unit and get back to work on things you actually want to do.
Good luck.
Good luck.