4020 PTO loud buzzing

[mmfarms]

I have an early 4020 that has rarely been
used the past decade that I've been going
through. I hooked it to a bushhog and it
was running OK, but with some noticeable
PTO whine. However, when I throttle down,
I have a very loud buzzing noise echoing
through the cab.

I'm not sure where to look. It only does
it while under load, unhooked there's no
noise. I took the clutch cover off, I
don't notice anything obvious there, the
bearings seem to be greased, there is some
oiliness can't tell which end its coming
from.

Going to try to post a video.

 

[mmfarms]

[video play=false:a51d6335d3]https://forums.yesterdaystractors.com/videos/mvvideo112125.mp4[/video:a51d6335d3]

 

[NY 986]

My casual impression is that the whine is relative to the PTO clutch as opposed to a bearing. Do you have an old implement tractor end PTO shaft to test the clutch by hand. I have one from an old Number 5 mower. Anyways, with the tractor engine shutoff and the PTO clutch engaged attempt to turn the tractor shaft via some kind of leverage to see if it slips. If so perhaps there is a bolt or two that has worked loose in the clutch assembly or worse case scenario the clutch assembly has extensive damage. If turning the shaft readily turns the engine over then possibly there is a bearing or some other issue.

 

[NY 986]

As a precaution the shut off knob should be pulled out or in the off position. If the tractor shuts off via the throttle lever then that lever should be pushed up as far as possible. Unlikely the tractor should start via the PTO but all precautions should be taken especially if the engine is still warm.

 

[gf in S.IL]

I don't have a cab on my 3020, but the little flat spring strip that is on the brake peddle lock (that locks the two brake peddles together) can vibrate and buzz loud enough I can hear it when using the PTO. Just a guess, but a cab might actually amplify it.

 

[used red MN]

To me that certainly sounds like gears that are not meshing properly. Something has worn or came out of place. Is it coming more from the back or down in the center of the transmission? Could be something has happened to the idler gear, see link. Use the right arrow on the JD page to see the gearing in the back. Any metal in the hydraulic filters?
JD 4020 parts catalog

 

[mmfarms]

There's definitely metal dust in the oil at bottom of the case, comes out silvery.

 

[mmfarms]

I replaced the rear pto seal recently, everything back there seamed OK to me.

 

[mmfarms]

Hard to tell exactly where it's coming from, the cab acts like a tuning fork. It's really loud though, way louder than the tractor, and seems to be coming from either the center of the transmission or maybe the clutch area, not the rear so much.

 

[WTW]

Based off your information: If tractor is a Syncrorange, if noise is only heard when using PTO and rear PTO 540 idler gear / bearing has been checked at rear of tractor, leaves only one place left and that is the PTO idler gear between PTO clutch shaft and PTO drive shaft. This idler gear is located on the end / front of the transmission differential shaft and has two rows of needle bearings. Same gear is used for the PTO brake Function. To access this gear the tractor has to be split between clutch housing and the transmission right under your feet. Once split the gear, bearing and PTO brake can all be easily serviced from the front of transmission. DW

 

[fdt860]

Worst case, the idler stub shaft has moved in the transmisdion housing.