Uncomfortable noise on finish mower

[Oldtink]

Yes, since your mower floats on the the ground and is behind what the tractor is running over, there is going to be differences in the two U-joint angles.
Take a look at the video and imagine your tractor is one end of the PTO shaft and your mower gearbox is on the other end and see what is causing the vibrations. All you can do is try to minimize those differences when mowing.
Driveshaft Angle and Phasing - YouTube

 

[dnw64]

Yes, since your mower floats on the the ground and is behind what the tractor is running over, there is going to be differences in the two U-joint angles.

It seems to me that as long as the system is properly set up, there should be no change in angle regardless of the height difference between Input and Output. And it seems to me that this would be one of the primary motivators for a slip joint in the PTO shaft - to allow the length to change as the implement ascends and descends.



Or, ASCII reference:


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[ddbackhoe]

It seems to me that as long as the system is properly set up, there should be no change in angle regardless of the height difference between Input and Output. And it seems to me that this would be one of the primary motivators for a slip joint in the PTO shaft - to allow the length to change as the implement ascends and descends.

View attachment 557277

Or, ASCII reference:


=--------=


=\
....\
.....\
......\=

It's not the length of the shaft but the angle of the joints. If you raise or lower the 3 point too much the ujoints will come into contact and create noise/issues. (Highlighted in attached drawing)
View attachment ujoint.bmp

 

[Oldtink]

Lets try this approach.

 

[dnw64]

It's not the length of the shaft but the angle of the joints. If you raise or lower the 3 point too much the ujoints will come into contact and create noise/issues. (Highlighted in attached drawing)

There is definitely no mechanical interference.

I believe the stated probable issue is a difference in angle of input and output shaft. They should be at 180°. I believe they are in normal operation. When the mower is lifted, that may change, although it shouldn't IMO if things are properly engineered.

 

[dnw64]

Lets try this approach.View attachment 557361

Yes, that is what I'm talking about. I don't believe that is the case. I know for sure that in normal operating mode they are both pretty near if not 100% (within normal person's measuring ability) dead level.

Lifting the 3-pt shouldn't IMO change the angle, although it may.

 

[Oldtink]

Yes, that is what I'm talking about. I don't believe that is the case. I know for sure that in normal operating mode they are both pretty near if not 100% (within normal person's measuring ability) dead level.

Lifting the 3-pt shouldn't IMO change the angle, although it may.[/QUOTE

That's wonderful if that's not what is happening.
I'm curious how you have your top link adjusted because when it is correct, the rear of the mower does droop down when you raise the three point hitch. Do you think that maybe the issue?