knocking noise

[BrokenTrack]

I know clutch rattle is a problem with Kubota's. Mine is older so it does not have a grease fitting for the throw-out bearing, but new Kubota's of the same model (2500/2501) do because it was such a problem for Kubota.

My John Deere bulldozer had a rattle too, but it was the flywheel dampener as it did not have a true clutch either. It had a clutch pedal, but it just disengaged the reverser hydraulically. Do you have an internal dampener on that rig?

 

[super55]

In PTSG’s case it would not be the throw out bearing. When he pushes down on the clutch it goes away. If it was the throw out bearing that is when it would make noise.

In my case it was the clutch plate rattling when clutch is fully depressed. If I let off just a bit it goes away.

You are absolutely correct K5lwq I completely misread his post. Good catch. I'm betting PTSG has the same issue you had. Possibly loose broken spring on the clutch disc. Thanks for correcting me.

 

[ptsg]

No heat shields on this one though. Well, just one under the exhaust manifold but it's tight. It does make the noise while sitting but, the again, if I press the clutch, it goes away.

PTSG your situation since it is a clutched tractor almost sounds like it could be the throw out bearing. I think your in the right direction looking toward driveline. How many hours are on the tractor and does the tractor have a grease fitting somewhere down by the foot pedal that goes to the bearing.

It's been doing this noise since I bought new. It has 220 hours now and didn't get any worse or better. It's no big deal, but if I could get rid of the noise on an easy way, I would. I'm very picky on every little noise I hear.

As K5 pointed out, it's only when I press the clutch. The throw out bearing is good and doesn't make any noise or vibration at all.

No way to grease the bearing either. Which is kinda disappointing that they don't add a way to grease the throw out bearing anymore these days. I had 1962 Italian crawler tractor that had a grease fitting with a flexible line to the throw out bearing and I'm pretty sure that is the reason on why the tractor still had the original bearing and still felt perfectly fine.

 

[K5lwq]

It is interesting that Kubota and Deere had the rattle as well. I don't hear it on the Kioti or the little Beaver. I certainly don't remember hearing that on the older big farm tractors we had. I am guessing it is the metallic clutch plate that is making the difference. At any rate, I don't believe it hurts anything but time will tell! :laughing:

 

[bindian]

No U-joints on these tractors. Straight shaft with splined couplers for the 4WD.

For the OP, since his tractor is an HST and doesn't have a clutch, I don't really know what the sound is.

On mine, is definitely something in the clutch. Probably just the springs on the clutch disc rattling around. Once it gets under load, it goes away. I'll take a inspection plate under the tractor and check the clutch stuff again.

I am not referring to you. I am referring to the drive joints at the steering knuckles on the OP. His noise is somewhere in the drive train.
hugs, Brandi

 

[super55]

It is interesting that Kubota and Deere had the rattle as well. I don't hear it on the Kioti or the little Beaver. I certainly don't remember hearing that on the older big farm tractors we had. I am guessing it is the metallic clutch plate that is making the difference. At any rate, I don't believe it hurts anything but time will tell! :laughing:

I'm with you on this one. If it's functioning properly doesn't seem to make a lot of sense to open it up to possibly solve a rattle. The kubota I had would do it but it was only in high gear and where i had to ride the clutch out a little more to keep it from stalling.

 

[metalbender]

Hard to define. Will it make the noise when stopped and just reving the engine? Would eliminate some drive train causes. Also, lifting the hood and playing the throttle while stationary might make it easier to identify the source. Vehicle tech for 44 years. Years ago, before cell phones, people would call for advice, we'd tell them to get it closer to the phone for diagnonsis. My guess is valve train noise. Will watch this thread. Any prize for the correct answer?

 

[rScotty]

Hard to define. Will it make the noise when stopped and just reving the engine? Would eliminate some drive train causes. Also, lifting the hood and playing the throttle while stationary might make it easier to identify the source. Vehicle tech for 44 years. Years ago, before cell phones, people would call for advice, we'd tell them to get it closer to the phone for diagnonsis. My guess is valve train noise. Will watch this thread. Any prize for the correct answer?

I agree. What I am hearing sounds to me more like valve train noise. Does it make it when stationary? I would check clearances and also check to see if the compression release is adjusted properly.

If it has an EGR type of emissions control, also check the manifold vacuum pressure driven poppet valve that controls the EGR gas flow.
rScotty

 

[jhamblett]

same, valve train noise

 

[nosaj2]

{UPDATE} Mine (original post) has been at the dealer since 6-30-2020 now. I checked on it Friday. It's not an exhaust issue. It not anything loose on the outside of the engine. It's not a throwout bearing or clutch related. (HST). They were going to check the valve train next. I hope they get it resolved too and it's not something major. I only had the little guy a few days but I sure miss him already.

 

[ruffdog]

My NH TC33D would sound like that once in a while. It was only at mid rpm and low load, just like the OP's tractor. My tractor was a 1999 and it never got worse with age and never made the noise while working. I would check the crankshaft thrust clearance with a dial indicator prying the crank forward/backward. If that checks out, I'd let it go. It doesn't sound like top end noise like piston/rod as those make noise right when throttle is applied. Excessive crank thrust will make noise at certain unloaded rpm's and when you chop the throttle. Like I said, verify the clearance, if ok, run it.

 

[rScotty]

{UPDATE} Mine (original post) has been at the dealer since 6-30-2020 now. I checked on it Friday. It's not an exhaust issue. It not anything loose on the outside of the engine. It's not a throwout bearing or clutch related. (HST). They were going to check the valve train next. I hope they get it resolved too and it's not something major. I only had the little guy a few days but I sure miss him already.

Sounds to this old mechanic like they are on the right track.
rScotty

 

[PILOON]

Am going way off topic with this----------

Had an airplane develop a slight knocking while I was at 5000 ft.
Would only knock when on both mags.
Really scratched my head thinking as to what it might be.
Knock got louder by the minute and as I cut power and the engine stopped dead!

Later teardown showed a crankshaft counterweight broken lose and jammed itself under a piston.
Thankfully I did chop power when I did otherwise pieces would have flown everywhere.

No injuries other than ego and a damaged aircraft.

 

[K5lwq]

Am going way off topic with this----------

Had an airplane develop a slight knocking while I was at 5000 ft.
Would only knock when on both mags.
Really scratched my head thinking as to what it might be.
Knock got louder by the minute and as I cut power and the engine stopped dead!

Later teardown showed a crankshaft counterweight broken lose and jammed itself under a piston.
Thankfully I did chop power when I did otherwise pieces would have flown everywhere.

No injuries other than ego and a damaged aircraft.

That is not fun! At least you had altitude to give you a little time to find a place to put the plane down. Could just as easily happened just as you clear the runway. Glad no one was hurt!

 

[nosaj2]

Sounds to this old mechanic like they are on the right track.
rScotty

That is good for me to hear Scotty.. I hope you are right.

 

[nosaj2]

[UPDATE]
The dealership could not determine what was causing the knocking sound. They had the Branson rep come down. The Branson rep suggested that they send it back to me and for me to drive it hard. I guess until what ever is causing that comes loose. I don't know. But I guess that is what I'm gonna do. They said they would replace it if it came apart.

 

[K5lwq]

Would be interesting to know what all they checked. When you get it back see if you can duplicate the noise without moving the tractor.

 

[TimberHole]

My wife took her car to the dealership a few years back for a noise. Every time she backed up it made a weird clunking sound. After 3 techs spent about 2 hours on it they figured out it was a can of hairspray rolling around under the drivers seat! :laughing:

 

[metalbender]

I can relate to strange noises. Back in the mid nineties, at the Mercury dealerahip, had a fancy Grand Marquis with a squeaking noise inside when turning corners. Was in the shop a couple times, techs couldn't isolate the noise. Also wasn't there on very humid days. Frustrated customer as well as the service manager. Finally came around to my turn. No flate rate, straight time, please take time to fix this. A ten minute drive with the shop foreman driving, me listening, the offending noise was located. Customer had a St Christoper medal on a key chain hung on the rear view mirror. It swung with the turns and squeaked till it stopped swinging. Service manager clocked me in for two hrs, thanks.

 

[rScotty]

Would be interesting to know what all they checked. When you get it back see if you can duplicate the noise without moving the tractor.

I still don't understand if it could make the noise when not moving? If it could, then I would do the following:

Yes, I'd still check valve clearances and the clearance on the compression release. That isn't a total of more than one hour mechanical time. Of course what they have for mechanics today are more like warranty part replacers. Their mechanic and service rep may neither of them ever set valve clearances. It's commonly done at 600 to 800 hrs.If so, I wouldn't want him learning on mine.

As for checking if the noise is a rattle coming from the EGR valve, it is simple to just find the rubber pressure hose from the manifold to the EGR mechanism and disconnect it to test. Pliug the hose temporily with a pencil. It's usually a small diameter hose - roughly 1/4 " diameter and fits onto barb connections.
rScotty