M7060 "buzzing" noise

[gpajimbo1180]

Hi All,

i have an M7060 that just turned 50 hours and has started making a buzzing noise from the transmission area. It is intermittent and usually below 1500 RPM.
Everything works and it does not matter if it is in or out of gear. i can't do anything to make it happen but usually changing the RPM's will make it go away.

Any thoughts or do the obvious and take it in?

 

[namesray]

My kubota mx5200 makes a "buzzing" type sound and it comes from the power steering lines under the steering wheel down by the foot platform. For what ever reason they have a zap sound that seems to be a pulse through the lines that cause the lines to vibrate. The lines have a plastic wrap over them and the power steering lines vibrating inside the plastic protective coating make a buzzing like sound. Changes with rpms too. I dont notice it at pto rpms, but right around 1000 to 1200 it really makes noise. Did it since brand new, drove me crazy for a bit, tearing things apart trying to figure it out. Never did figure out why, but I now have over 800 hours with no problems, so I just run it.

Your sound might be something different, but reading your post made me think of my "buzzing" sound. You saying comming from transmission area, my power steering lines I can imagine the sound comming from the transmission area. Both kinda close on my model. Dont know about yours? When your power steering lines aren't too hot to touch, lightly hold them and see if they vibrate when your buzzing sound is going on. Might not be your issue, but might be worth a try to narrow down your issue. Good luck.

 

[JWR]

I spent many years analyzing vibration data from aircraft and helicopters. I think you are dealing with resonance -- where something is sensitive to the frequency of vibration put out by your diesel engine. I seriously doubt that it is anything bad wrong or cause for concern. I had a buzz once coming from a tool box.

Try this: Set your rpm to whatever speed maximizes the noise. If you can't make it happen it will be very tough to cure. Try varying the rpm very slowly up and down and you will probably find the sweet spot where it hums or buzzes. Set the brakes or block it in place and start feeling around in the area where the noise seems to be coming from. See if you can put finger pressure on a fitting or line or cable or piece of sheet metal (anything really) that will stop the noise or affect the noise. As Namesray suggested above, metal hydraulic lines are notorious for making these kinds of noises. You may even locate a screw or bolt that is not tightened and begins to hum or vibrate at a certain rpm. Some people borrow or buy a stethoscope (just like a Doctor's except with a probe at the end rather than the round flat sensor. A std stethoscope with the sensing end pulled off and an open tube exposed works fine. Auto parts places sell them too I think.) That allows you to search around and narrow down the location.

Being such low hours, my first suspicion is something not tightened down very well before it left the factory.

Once located you can usually tighten up the part or item, insert a small wedge or spacer, put in a piece of rubber as a cushion, etc. and cure the noise.

Especially since you can make it go away by altering the rpm it is almost certainly a resonance -- where the natural frequency of a part or piece matches the frequency of the source of the vibration.

 

[zoltanthegypsy]

I don't have JWR's experience, but I was also going to suggest trying a stethoscope - if you can safely do so. Even a chunk of garden hose can work, and may let you reach places you couldn't with a medical 'scope.

A doctor friend gave me a 'scope years ago. It has a toggle on the end to switch from an open-ended bell to flat sensor and back as needed. Surprising how often I use it.

Z.

 

[gpajimbo1180]

Thanks for the replies. I'll start snooping around and see if I can find the culprit.
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