Kubota M7040 "clunking noise"@idle

[NICOT]

Great site! Looking for help with my new Kubota M7040,HD, FWD,It makes a mysterious "clunking" noise during idle, while every other function runs just fine. Any help would be greatly appreciated. Upstate PA,Thanks; nicot

 

[SPYDERLK]

In neutral only? Probably rattle in the input shaft for the transmission due speed variation from firing pulses. See if pushing the clutch in will stop it.
larry

 

[NICOT]

In neutral only? Probably rattle in the input shaft for the transmission due speed variation from firing pulses. See if pushing the clutch in will stop it.
larry

Thanks, SPYD, for the response. With the Kubota m7040 Hydr.Shuttle in neutral, I sometimes leave the stick shift in gear when in idle and hear the "clunking," noises. I'll try putting the stick shift (gear) lever in neutral too, as you recommend. And try the clutch deal too. Some of my research, thus far, has led me to Service Bulletin 7-11 (hydraulic oil cooler bypass pressure valve). What do ya' think; Thanks much; Nicot in PA.

 

[leonz]

Do you have an accumulator in the hydraulic circuit? it would cause this noise form filling and emptying the stored pressure.

 

[NICOT]

Thanks for the response on the M7040, calling the dealer today, will get back to you all soon regarding the issue. Any suggestions are still welcome, great site! Nicot, PA

 

[NICOT]

Relative to the M7040 "clunking noise" sitting in idle, I brought it out today, put the hydro. shuttle in neutral and gear lever in neutral after warming it up; and there was no "clunking noise" yet. One Kubota dealer says another M7040 had similar issue, they tore it apart and Kubota reps. looked at it and nothing was found wrong. It was determined as just "the nature of the beast", so to speak. Any of ya'll feel I'm being hoodwinked? Speak up! Still have another year on the transmission warranty. Thanks; Nicot in PA.

 

[TripleR]

I know they are different machines, but my M8540 makes no such noise, but if it did, I would be concerned.

I am curious; you say it is "new":

1. How many hours?
2. Did it just start?
3. How is it set up or what is it hooked to?
4. What is your idle speed?
5. At what RPM is it worse?
6. When does it stop?
7. What do you consider warmed up?

I am no mechanic, but it might help someone with the diagnosis.

 

[SPYDERLK]

Relative to the M7040 "clunking noise" sitting in idle, I brought it out today, put the hydro. shuttle in neutral and gear lever in neutral after warming it up; and there was no "clunking noise" yet. One Kubota dealer says another M7040 had similar issue, they tore it apart and Kubota reps. looked at it and nothing was found wrong. It was determined as just "the nature of the beast", so to speak. Any of ya'll feel I'm being hoodwinked? Speak up! Still have another year on the transmission warranty. Thanks; Nicot in PA.

Youll have to satisfy yourself that it is safe to ignore. Keep sleuthing for the combination that causes it - while its happening, play to see what changes it. For instance, as rpm increases does it just fade out and go away? If pushing in the clutch affects it, it could be transmission rattle as I described -- or could be endplay in the engine crankshaft. If the latter, just resting the weight of your leg on the clutch pedal [not enuf to disengage it] should affect the sound. If it turns out to be that raise a flag to Kubota. Altho probably not a problem, you want them to check it and say so.
larry

 

[Yankee Clipper]

Nicor,

Spyderlk's first post was right on about the torsionals the engine generates a low idle and how they are amplified through the unloaded powertrain components.

Good luck with the tractor!

 

[Chilly807]

Could well be drivetrain torsional vibration. I once stripped a Chevy 4 speed down to nuts and bolts, replaced every bearing in it, and had EXACTLY the same rattle when I was done.

It might be worth asking the dealer to compare it to another tractor, same model if they have one.

Sean