knucking in a 3720

[Deere Dude]

Maybe one of you can shed a little light on my 3720. I get an audible knucking sound when idling, wheels turned to right or left, Idling so I can hear easier. Wheels straight, it seems fine.I tap the hydro pedal to go forward or reverse, and let off the pedal I hear a sound that comes from the frame section someplace. I don't ever remember hearing that before.

It is a 2010, 3720 with 125 hrs. I checked the lug nuts and they are tight. I didn't see any loose hardware. I took the loader off, the 3 point attachment off. I took the top link off. I tied the 3 pt. lift arms together with a bungy cord. I looked underneath and don't see any loose stuff. The only thing that wiggles is the drive shaft for the front end. Boy is that thing wimpy, by the way.

If anyone else has noticed that on yours and know of a fix, please let me know. It's under warranty yet and if I don't find an easy fix by tomorrow I'll have to take it to the dealer. Thanks in advance,

 

[AKfish]

I gather from your comments that the noise occurs when the tractor is not moving - but, whenever you turn the steering left or right, yes?

Sounds like it could be a problem with either the steering valve, the steering cylinder or the hydraulic pump for the power steering.

Of course, if you're turning the wheels to the very "dead-end" of the steering travel you'll have a noise from the hyd pump going to relief or bypass.

AKfish

 

[Caledon Hills]

Maybe one of you can shed a little light on my 3720. I get an audible knucking sound when idling, wheels turned to right or left, Idling so I can hear easier. Wheels straight, it seems fine.I tap the hydro pedal to go forward or reverse, and let off the pedal I hear a sound that comes from the frame section someplace. I don't ever remember hearing that before.

It is a 2010, 3720 with 125 hrs. I checked the lug nuts and they are tight. I didn't see any loose hardware. I took the loader off, the 3 point attachment off. I took the top link off. I tied the 3 pt. lift arms together with a bungy cord. I looked underneath and don't see any loose stuff. The only thing that wiggles is the drive shaft for the front end. Boy is that thing wimpy, by the way.

If anyone else has noticed that on yours and know of a fix, please let me know. It's under warranty yet and if I don't find an easy fix by tomorrow I'll have to take it to the dealer. Thanks in advance,

Right in the center of your front axle pivot there is an adjuster bolt to remove play. Loosen the jam nut and turn clockwise in very small increments while testing until the noise goes away. Make sure the jam nut is tight when done. Good luck.

Regards,

Tom

 

[Chuck on lake]

I don't know if this is the cause but maybe. I had a gear crunching type noise with my 3720 that came at 2400 RPM and disappeared slower or faster. Dealer traced it to the small hydraulic line as it leaves the pump. He fastened the line with a clamp and the noise disappeared. As I understand it there are two lines running from the pump, large and small and it was the small one vibrating.

 

[Deere Dude]

I gather from your comments that the noise occurs when the tractor is not moving - but, whenever you turn the steering left or right, yes?

Sounds like it could be a problem with either the steering valve, the steering cylinder or the hydraulic pump for the power steering.

Of course, if you're turning the wheels to the very "dead-end" of the steering travel you'll have a noise from the hyd pump going to relief or bypass.

AKfish

No, the tractor has to be moving a couple feet to make the sound. There is no noise when I turn the wheel, but there is if the wheel is turned already and then I give it a micro-tap while idling on the hydro, then I hear the noise. The same noise happens in reverse also. I'll check again for loose stuff underneath, maybe I can narrow it down more.

 

[Deere Dude]

I don't know if this is the cause but maybe. I had a gear crunching type noise with my 3720 that came at 2400 RPM and disappeared slower or faster. Dealer traced it to the small hydraulic line as it leaves the pump. He fastened the line with a clamp and the noise disappeared. As I understand it there are two lines running from the pump, large and small and it was the small one vibrating.

Okay, I'll check for loose hydro lines. Maybe a clamp came off???

 

[Deere Dude]

Right in the center of your front axle pivot there is an adjuster bolt to remove play. Loosen the jam nut and turn clockwise in very small increments while testing until the noise goes away. Make sure the jam nut is tight when done. Good luck.

Regards,

Tom

You nailed it Tom. That's what it was. Thanks a lot. The bolt was turned out about 3 or 4 turns and the lock-nut was loose. I tightened it up and the noise stopped.

I may have messed up though. I turned it in by hand until it stopped, then I give it another 1/2-1 turn with a wrench until tight and then tightened the lock-nut. I didn't do the incremental adjustments. What do you think? Should I back it out until the noise starts and then turn it in a little bit, or just leave it?

 

[Caledon Hills]

You nailed it Tom. That's what it was. Thanks a lot. The bolt was turned out about 3 or 4 turns and the lock-nut was loose. I tightened it up and the noise stopped.

I may have messed up though. I turned it in by hand until it stopped, then I give it another 1/2-1 turn with a wrench until tight and then tightened the lock-nut. I didn't do the incremental adjustments. What do you think? Should I back it out until the noise starts and then turn it in a little bit, or just leave it?

Glad to hear it worked out for you.
More than likely your adjustment is OK. The torque spec on that bolt is 24 ft-lbs. wheels off the ground, so there is some preload (your 1/2- 1 turn in). To be 100% sure borrow or buy a torque wrench if you don't have one and set it to spec.
One other thing NEVER work under suspended equpiment without secure support i.e axle stands etc. Have a great day.

Regards,

Tom

 

[Deere Dude]

Glad to hear it worked out for you.
More than likely your adjustment is OK. The torque spec on that bolt is 24 ft-lbs. wheels off the ground, so there is some preload (your 1/2- 1 turn in). To be 100% sure borrow or buy a torque wrench if you don't have one and set it to spec.
One other thing NEVER work under suspended equpiment without secure support i.e axle stands etc. Have a great day.

Regards,

Tom

I had extra time so I jacked the tractor up and noticed that the bolt I tightened a few days ago was out a few turns again. This time I locktited it at 24 ft lbs. That should keep it in there. Thanks for the tip Tom.

Chuck

 

[shortthrow50]

i know this is an old thread but my machine only has 60 hours on it and i noticed this same issue about 10 hours ago and has been bothering me. Im 98 percent sure this is my issue as well becuase when i back into my garage, i hear the noise as the front tires hit the concrete lip and see the whole axle move. Cant wait to check torque on this bolt you guys are talking about. Thanks