4720 3PH Whine & Steering Wheel Vibration

[Engine66]

I took delivery of a new 4720 this last December and have about 35 hours on it so far. Amazing machine so far...overall very happy. However, I was working the tractor in the woods with a rear Landpride 2584 rake and after a while of going back and forth and up and down with the 3ph to clear debris, I noticed a whine coming from the 3ph on lifting. It would start to whine about 2/3rds the way up and I could feel a vibration in the powerbeyond and rear remotes with my hand. It performed well...just made the noise. Also, I could feel a vibration in the steering wheel at about 1500 rpms. I believe the noise and vibration is from the HST and am wondering if this is normal or what? Hard to describe noise...almost sounds like a gravely type whine and the vibration in the steering wheel goes away with higher rpms. I did read another thread about similar stuff and a technical bulletin being issued last year. Any thoughts or info? Thanks.

[shot_gun]

Here is what I found. Hope it helps.


On tractors equipped with the Power Beyond Kit verify that the non-screened fitting is installed at the rockshaft valve inlet.

The screened fitting is identified with notches cut into the corners of the wrench flats. If the fitting installed has these notches you will need to replace it with the non-screened fitting part number 61M5004.

On all tractors:

Verify that the steel lines feeding the rockshaft valve are not contacting the rockshaft housing or any other external part.

[shot_gun]

On the steering noise that is normal. Pulses of the hydraulic pump cause a harmonic vibration that resinates through the steering block and at certain engine speeds you hear it more than others. You can lessen the noise by taking apart the plastic around the steering column and get sound reducing material and wrap it around the steering pump. That usually does a pretty good job.

[Engine66]

Shotgun...thanks for the info...I looked at my rockshaft valve and there's no notches in the corner, but one side of the wrench flats has a "tire tread" type pattern on it. Is this the right one or should I have my dealer come take a look? Re: steering...I can live with it...just want to make sure it's normal and not an issue that needs to be fixed. Thanks again.

[shot_gun]

I belive that is the one you are supposed to have. If you have any doubts check with your dealer and have them double check it.

[AKfish]

Hmm... I've got a "harmonic chirp" coming from one of the hydraulic pumps on my 110. It is most noticable at idle or slightly above and can be felt up thru the steering wheel.

Shop mechanic at the local dealership thought that the 3pt was in the "full raise" position when I installed the backhoe. The owner's manual instructs that the 3pt needs to be completely lowered when installing the backhoe.

However, it has "chirped" since I got it from the dealer and I don't recall if the 3pt was raised or not when I picked it up...

Have since reinstalled the hoe and haven't noticed the pump noise -- at least as frequently as before.

Wonder if the hydraulic coupler issue applies to the "yellow" tractors, too?

AKfish