BX23 Ujoint / new vibration question

[Ex Five 0]

Hello to all tractoring dudes. I am reaching out to our collective knowledge base to get some answers regarding a repair/operation issue involving my 12 year old 800 hour BX23 TLB.

Sorry for the long story, but I wanted to include as much background data as possible.

The slope of my property requires 4WD use for most areas. Towards the end of last summer, while mowing with a 48 landpride rear mower, I noticed that I had lost drive to my front wheels. A look under the tractor immediately disclosed that I had lost middle Ujoint for the front drive shaft. I backtracked the area that I had mowed but was unable to recover the lost part. I ordered a replacement ujoint assembly and roll pin and completed the simple repair.

The next time I mowed, I noticed a vibration when the 4WD was engaged. Since I had also recently replaced the front tires, I chalked up the vibration to the tread on the new tires (the old set were essentially baloney skins)

Now, I am noticing that what I thought was tire tread vibration, is in fact only present when 4wd is engaged. I did a test by putting the tractor up on stands and testing for the vibration by running in 2wd and 4wd. The test confirms the source of the vibration is somewhere in the front wheel drivetrain.
I have also found the lost ujoint and have attached several pics of its condition when it was found. Note that there is a portion of the roll pin still in place.

So I have 2 questions:
1) How is it possible to shear off the roll pin without damaging the Ujoint splining.
2) What sort of damage also occurred to the front drive train during the ujoint event that has led to the vibration?

I would luv to hear your thoughts, suggestions and advice.
Brian

 

[skipperbrown]

I am going to speculate that your front drive train is bent somewhere assuming there was no vibration before the incident. When the U joint failed, did the shaft drag the ground and perhaps get bent?

 

[ptsg]

Another speculation here. Are both U joints phased correctly?

 

[oosik]

Correct phasing would be my first guess. Second - was the replacement an EXACT OEM replacement part. Third - bent shaft. Any of these three could easily cause vibration.

 

[Ex Five 0]

I also thought thought that that the shaft might have been bent by dragging/impacting the ground. yesterday, I removed the shaft, removed both Ujoints, and rolled it around on a flat piece of glass. The roll test seemed to confirm that it was straight. I am wondering if the front Ujoint was damaged in the event and is the cause of the vibration.

 

[Ex Five 0]

What is correct phasing?

 

[Ex Five 0]

I looked up driveshaft /Ujoint phasing and found some terrific youtube videos. As soon as it stops raining here, I will give phasing a go.

 

[Ex Five 0]

I properly phased the two Ujoints and the vibration is gone. Thanks to all who responded to my post and pointed me in the right direction

 

[bigtiller]

Your luck is a little like mine.... I think if I guess at a true-or-false question, I am wrong 75% of the time. :laughing: