John Deere 4300 Three Point Hitch Problem

[Michael Corrigan]

I have a John Deere 4300 HST tractor. It only has about 830 hours and has been a great tractor. Here is my situation: The three point hitch raises and lowers just fine. However, when I have weight on the three point hitch such as a finishing mower in the raised position, it makes an awful erratic noise and occurs about every other minute. The noise sounds terrible but I believe it is just hydraulic oil passing thru a tight area creating this sound. What appears to be happening is that the hitch is losing lift and it automatically adjusts itself back to the set height. Could this me the rockshaft cylinder o ring bad allowing oil to pass thru which causes the hitch to lower so very slightly? I would appreciate any feedback to help diagnose the problem.

Thanks,

Michael

 

[beenthere]

Is it happening when at low rpm and stops making noise when the rpm's are increased?

:welcome: to TBN

 

[larboc]

I have to ask, did you check fluid level in the axle?

Sounds like a leaking rockshaft cylinder, not going to be easy to get to, I'd probably try to ignore it for as long as possible.

 

[Michael Corrigan]

This is happening at any RPM.

 

[Michael Corrigan]

Thanks

 

[mike48130]

I think there is a separate pressure relief for the rockshaft. Sounds like either that or the cylinder seals.

 

[Kyle_in_Tex]

Does it raise and lower properly in increments? Like when the lever is halfway, the 3 pt is halfway between its high and low positions?

Does it move smoothly up and down in small increments.

 

[Michael Corrigan]

The three point raises and lowers in all increments just fine. If you have weight on the three point and slowly pull the lever as to raise the hitch you will hear the noise very clearly on the LH side of the case. A couple of years ago I removed a small wire screen in the same case. It had come loose and was wedged in the valve and as a result I did not have any hydraulic pressure to raise the hitch. The noise I am hearing is definitely from oil squeaking thru somewhere. I'm thinking this noise is normal but probably the seals on the cylinder for the rockshaft are bad and everytime the hitch begins to lower on its own due to the leak it adjusts back to its selected height.

 

[beenthere]

Seems I recall that the screen had a chance to move into the valve and may have scored it some. Might be just something you need to get used to or tear into the valve if so motivated.
We're interested in what you find and what you do.
I changed that screen before it dislodged, based on comments read here on TBN, many moon ago.. I get a noise at low rpm on early (cold) startup. Doesn't sound like what you describe.

 

[Michael Corrigan]

Well, I found the problem. I took the rock shaft valve box off again and there was another screen raveled up and stuck in the valve. I had taken one of these out of the same box a few years ago when I had problems with the three point hitch being completely dead-no movement at all when the lever was raised. So, I pulled the screen out along with the small fragments. I took the valve out, flushed it, installed new O-Rings and it seems to work just fine. Thank You All for your input and helping me resolve this problem.

Have a Great Weekend!

Michael