Nashville TJ's Build - Continued

[gasiorv]

I just did a little research on the 14 bolt (I never worked on one in person) and the adjuster screw in lieu of the shims is nice! Kind of like a Toyota or 9 inch third member.

 

[NashvilleTJ]

Is your backlash the same in 4 quadrants? Watching the ring gear wobble in your video makes me ask.

I only checked backlash in one place. In hindsight, I should have checked in four (good practice anyway) because it was probably moving around given the play in the bearing.

I don't know if the ring gear is actually wobbling. As I said, the movement seems to be on the non-tooth side, perhaps something to do with the way Yukon shaved it. The tooth side seems to be running true - but hard to tell. I only noticed the "wobble" when I watched the video. I did not notice it live. But, live I was paying close attention to the tooth side, and it seemed fine.

Edit: I just took a close look at the raw video (which is much higher resolution than on YouTube), and it's very clear that the tooth side is true, but the left side along the cut line moves a bit. Again, looks more like a sloppy shave job by Yukon.

 

[NashvilleTJ]

Back and forth as in left and right or fwd and aft? I don't see how it would move left and right if it was shimmed right so I am assuming it is fwd and aft, up and down, all around. So if my assumption is correct and your shaft is out 0.022 then it would wobble with the shaft rotation and make the same noise every rotation.

I really don't understand how it is wobbling or moving 0.014 with the tight fit, I would think the bearing pushing on the carrier would keep it locked in place, how is it shimmed right if the bearing isn't seating fillet to fillet? Something has to be hitting

Hitting is a bad word, it typically means bad. So maybe this is better - there has to be contact between bearing inner race and carrier for it to shim tight.

Thinking about this, more than likely the case bearing adjuster would be tight enough keep the bearing from moving around - and they were tight when disassembled. But since the bearing collar had 14 thou of movement around the bearing surface, the diff was likely pushed 7 thou off center, held in that position by the bearing adjusters, and perhaps that would create binding - and the noise - on one side of the bearing. Just a wild guess, of course.

 

[Woodrow]

I only checked backlash in one place. In hindsight, I should have checked in four (good practice anyway) because it was probably moving around given the play in the bearing.

I don't know if the ring gear is actually wobbling. As I said, the movement seems to be on the non-tooth side, perhaps something to do with the way Yukon shaved it. The tooth side seems to be running true - but hard to tell. I only noticed the "wobble" when I watched the video. I did not notice it live. But, live I was paying close attention to the tooth side, and it seemed fine.

Edit: I just took a close look at the raw video (which is much higher resolution than on YouTube), and it's very clear that the tooth side is true, but the left side along the cut line moves a bit. Again, looks more like a sloppy shave job by Yukon.

I forgot about the ring gear shave. That could do it, I guess. OK as long as the side against the carrier is true (flat).

I mentioned doing my AAM 11.5 gears somewhere recently. On attempt no. one, the back lash was out by 3 or 4 thousandths around the ring. In that case, it ended up being a tiny "bump" on the yukon pinion where the shims sat. It actually put a tiny dent in the first couple of shims and was apparently enough to skew the bask lash around the ring. I ground it off carefully and problem solved.

 

[NashvilleTJ]

Here is a look at the play in the carrier bearing:

 

[hosejockey61]

Here is a look at the play in the carrier bearing:

Looks like a problem for @Wildman

 

[NashvilleTJ]

I just took a close look at the ring gear on the bench, and put it under the mic. It is dead true, but there is an uneven mark around the edge of the milled (shaved) surface that makes it look like it's wobbling in the video. At least it's not wobbling as much as it appears in the video.

But, if the bearing was off center by 7 thou, maybe it was wobbling enough to bind the bearing, and make some noise, but likely not enough to see in the video.

 

[NashvilleTJ]

Given all this, my bet is that when I install the new carrier and new carrier bearings, the binding and noise goes away.

What say you boys?

 

[Wildman]

Looks like a problem for @Wildman

Yep but I knew that walking into it...

 

[NashvilleTJ]

Spending some more time with the high-def video, I'd swear I'm seeing a bit of up and down movement, exactly in time with the rotation, right here:

I may be imagining it, and perhaps a bit of confirmation bias - but I'm goin' with it!

 

[Wildman]

Given all this, my bet is that when I install the new carrier and new carrier bearings, the binding and noise goes away.

What say you boys?

Fingers crossed for ya....

 

[hosejockey61]

Given all this, my bet is that when I install the new carrier and new carrier bearings, the binding and noise goes away.

What say you boys?

For awhile anyway...

 

[Wildman]

For awhile anyway...

Now that is just mean...

 

[NashvilleTJ]

For awhile anyway...

I've been thinking about that too, Mike. Thinking back to the root cause, and whether this will simply happen again.

The original failure of this bearing surface occurred along with the failure of the pinion gear. As I've said I was hearing the exact same noise at that time that I was this time - leading me to believe I'd once again smoked the pinion gear. Remember, I think I ran it that way for a couple of years - including at least one trip to Moab.

Maybe the noise I was hearing at that time was not the failed pinion gear itself, but rather was caused by the worn and loose bearing journal - just as it is now.

And perhaps the original failed pinion gear somehow caused the bearing journal failure, or at least had something to do with it?

As Blaine said, my dimple fix was not done correctly, did not last, and once again caused the noise after it wore sufficiently away. That bearing journal is basically now back to the way it was before I attempted the dimple repair - and the same noise returned.

Maybe the root cause of both of these noise incidents was the original pinion gear failure. And I'm still thinking debris for the cause there.

Grasping at straws I know, but it's the only thing I can come up with that makes any sense and fits all the facts.

 

[Wildman]

I've been thinking about that too, Mike. Thinking back to the root cause, and whether this will simply happen again.

The original failure of this bearing surface occurred along with the failure of the pinion gear. As I've said I was hearing the exact same noise at that time that I was this time - leading me to believe I'd once again smoked the pinion gear. Remember, I think I ran it that way for a couple of years - including at least one trip to Moab.

Maybe the noise I was hearing at that time was not the failed pinion gear itself, but rather was caused by the worn and loose bearing journal - just as it is now.

And perhaps the original failed pinion gear somehow caused the bearing journal failure, or at least had something to do with it?

As Blaine said, my dimple fix was not done correctly, did not last, and once again caused the noise after it wore sufficiently away. That bearing journal is basically now back to the way it was before I attempted the dimple repair - and the same noise returned.

Maybe the root cause of both of these noise incidents was the original pinion gear failure. And I'm still thinking debris for the cause there.

Grasping at straws I know, but it's the only thing I can come up with that makes any sense and fits all the facts.

So what is your plan once the new ARB arrives?

1) Replace the locker & R&P?

2) Replace just the locker? And still run the Yukon gears and keep the new gears as back up?

And on a side note, without calling ARB yet it appears that the side case 013201SP is on back order right now... And it's about what I remember when I had to replace part of mine in my CRD60 @ $390 .

 

[hosejockey61]

So what is your plan once the new ARB arrives?

1) Replace the locker & R&P?

2) Replace just the locker? And still run the Yukon gears and keep the new gears as back up?

And on a side note, without calling ARB yet it appears that the side case 013201SP is on back order right now... And it's about what I remember when I had to replace part of mine in my CRD60 @ $390 .

The 1/2 cases are almost always on back order no matter the axle. I just don't think they stock them. More of a make an extra on the next batch. I had to buy a 1/2 once and had to wait as well.

 

[Wildman]

The 1/2 cases are almost always on back order no matter the axle. I just don't think they stock them. More of a make an extra on the next batch. I had to buy a 1/2 once and had to wait as well.

Which was why I was offering to buy it off Jeff... I'll order the half since I don't have plans to even start trying to build these new axles until this fall or later.

 

[Woodrow]

I just took a close look at the ring gear on the bench, and put it under the mic. It is dead true, but there is an uneven mark around the edge of the milled (shaved) surface that makes it look like it's wobbling in the video. At least it's not wobbling as much as it appears in the video.

View attachment 666411

But, if the bearing was off center by 7 thou, maybe it was wobbling enough to bind the bearing, and make some noise, but likely not enough to see in the video.

That explains the video wobble. The lines in the metal extending down from the roots of the gears are interesting. Are these things made by some type of hot forming rather than being cut from an unmanipulated block of steel (probably not using the correct terms)? I think I recall splines on axle shafts can simply be cut or they can pressed into heated metal and the latter is stronger.

 

[NashvilleTJ]

So what is your plan once the new ARB arrives?

1) Replace the locker & R&P?

2) Replace just the locker? And still run the Yukon gears and keep the new gears as back up?

...

I'll run the same R&P, and keep the new Crown Unit for a spare.

Reasons:

1) If I replace the R&P, along with replacing the locker and the bearings, and the noise goes away - I won't know if the cause was the failed bearing journal as I suspect, or the R&P.

2) I can reinstall the current R&P without setting up the gears - I'll press on the new carrier bearings, set the backlash, and be done with it.

3) The current R&P gears look brand new. No wear at all. Probably only 1000 or 1200 miles on them.

4) I've been planning for a while to get and keep a spare R&P, since being shaved they are custom. That was my fallback when I ordered them in that if it turned out not to be the R&P (which it likely was not), I'll have a good spare. If I install the new R&P now, I don't have a spare as I would not reinstall a set of old gears down the road.

 

[NashvilleTJ]

That explains the video wobble. The lines in the metal extending down from the roots of the gears are interesting. Are these things made by some type of hot forming rather than being cut from an unmanipulated block of steel (probably not using the correct terms)? I think I recall splines on axle shafts can simply be cut or they can pressed into heated metal and the latter is stronger.

No idea. Since they are Yukon gears, my guess is that they are not manufactured using the most sophisticated processes...

In comparison, the Crowne Racing gears do not have that feature: