Does this look right?

[xrocketengineer]

I have been feeling (not hearing) a slight knock when in 4wd. I went looking for possible missing pins on the forward U joint but they seem to be there. However, I found play everywhere. There is plenty of oil in the axle housing.

 

[North Idaho Wolfman]

Pull the shaft and U Joint off and inspect the splines on both the U joint and the shaft.

 

[xrocketengineer]

I pulled the U joint and I did not find anything obvious. The differential input shaft was tight with no play axially nor radially. The splines look good to me.

The drive axle splines also look good to me too.

The U joint was not loose and again nothing seemed out of the ordinary.

Differential input end.

Drive shaft end

Even the pins don't look bad. You can run a finger nail along their length and it does not catch and they feel smooth. They fit tighter on the on the shafts than on the U joint but it is not a "press fit" on either.

Normal wear and tear? Tolerance build up? Reassemble with some grease to reduce the perceived knocking? Replace the U joint and/or pins?

These mysteries to be revealed on the next episode of "As the Kubota axle turns" ...

 

[xrocketengineer]

I just noticed that the seal on one of the bearings of the U joint is peeling off. Might as well replace everything.

 

[North Idaho Wolfman]

When you rotate the input shaft right and left, is there lots of play?

 

[xrocketengineer]

There is some rotational play on the input shaft. I am not sure how much is a lot. Besides, the front axle is now on Jack stands which makes it harder to determine if a tire start to turn. Let me figure something out.

 

[xrocketengineer]

Ok, here is how much play I have. For the initial motion I had some tire rotation but not after that, the chocks worked well.

http://imgur.com/a/iWV9bTi

 

[xrocketengineer]

Well, I reassembled all the new parts, they all fit much more snugly with no play. The exception is the gear backlash which I am going to declare Ok for the time being since I only have 345 hrs. on the tractor.
Regardless, the old U joint had a very loose fit on both ends even though the splines did not look bad . Its amazing to me how much better the new parts fit .