Nashville TJ's Build - Continued

The long side - passenger - shaft was out of true about 15 thou in the center. The short side - driver - shaft (the side on which the carrier bearing spun) was out 8 thou. I don't know what the specs are on these things, but that seems close enough. Is this a reasonable level of straight?

I would think that would be okay, but I have no personal engineering experience with live axles to base that opinion on. I would think that the splines being a loose fit gives some allowance for runout.
 
I would think that would be okay, but I have no personal engineering experience with live axles to base that opinion on. I would think that the splines being a loose fit gives some allowance for runout.
I was thinking the same (not that my thoughts on the subject are worth anything, but its nice when I have a thought identical to the more experienced folks :))
 
Jeff, looking through your build thread, it looks like you built that axle about four years ago. Since you're an old feller like me, :cool: is it possible you heated that bearing and dropped it on instead of pressing it on? If so, it's possible that the journal was slightly too small and you didn't notice it. I'm baffled as to how the inner race spun if it was an adequate press-fit.

Edited to answer my own question: I went a bit more forward in this thread, and there are pics of you pressing the carrier bearings on. {scratches head}
 
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Jeff, looking through your build thread, it looks like you built that axle about four years ago. Since you're an old feller like me, :cool: is it possible you heated that bearing and dropped it on instead of pressing it on? If so, it's possible that the journal was slightly too small and you didn't notice it. I'm baffled as to how the inner race spun if it was an adequate press-fit.

Edited to answer my own question: I went a bit more forward in this thread, and there are pics of you pressing the carrier bearings on. {scratches head}

Yeah, the forum is a good source of my memory as well...

Old feller? I'm 38.

:rolleyes:
 
I'm still waiting on the pinion shims to arrive, but I did go ahead and get started. A nice thing about the 14 bolt is that you set up the pinion gear and bearings completely independent of the rest of the diff.

First up, install the two bearing races in the pinion housing. Easily done with a bearing race installer:

IMG_5332.webp


Then press the inner bearing onto the pinion bearing shaft.

IMG_5333.webp


All set. That's the crush sleeve eliminator sleeve on the right.

IMG_5334.webp


Another tool I built which comes in handy is this yoke holder to allow torquing (and untorquing...) of the yoke. It's also handy when it comes time to rotate the pinion to get a pattern. It bolts to the yoke and will stay there until the entire gear setup is complete.

IMG_5335.webp
 
Since I had a previous working setup, my first assembly uses the original pinion shim stack. I went ahead and installed the sleeve, the shim stack, the bearing and the yoke, and torqued it down. I did not get too far before the yoke bound, so I definitely need more shims to spread the bearings apart a bit, and therefore reduce the preload. The shims should be here shortly.

The entire thing can be done in the vise, which is quite nice.

IMG_5337.webp


One thing to note for anyone paying close attention. In this pic the assembly is sitting very loosely in the vice as I was getting everything ready. The rear section of the bolt flange is a sealing surface, and it needs to be protected from damage. I didn't take a pic, before I tightened the vise and I torqued the pinion down I added and aluminum guard to the rear vide face to protect the sealing surface.

And for what will be the first of many times, back over to the press to press out the pinion shaft.

IMG_5338.webp
 
While I'm waiting, another prep step is to clean, mic and mark the pinion bearing shims and the pinion housing shims.

IMG_5339.webp


IMG_5340.webp


Now if the rest of those pinion shims would show up I can get this party started... :cool:
 
The shims finally came in last night, and I did spend a little time getting the pinion dialed in. First up, I mic'd and marked the rest of the pinion preload shims:

IMG_5351.webp


The first setup at 88 thou locked the pinion bearing, indicated not nearly enough shim. So to bracket the results, I moved up to 101 thou.

This is the pinion bearing stack. The sleeve sits on the bearing, and the shims sit on the sleeve.

IMG_5345.webp


The pinion housing drops down onto the inner bearing, the outer bearing drops in, and finally the yoke and nut. The outer bearing is a press fit and is drawn down with the pinion nut using an impact. The yoke tool helps a lot here:

IMG_5348.webp


The final torque on the pinion nut is 250 foot pounds. Even with this long torque wrench, it takes some effort.

IMG_5341.webp


Finally, you test the pinion bearing preload using an inch pound dial torque wrench. On the 14 bolt, the pinion bearing preload target range is 20 - 35 inch pounds. At 88 thou of shims, the bearing bound. Now at 101 thou, the bearing preload was 0, but at least I had the bracket.

IMG_5349.webp


Then you start again. Back to the press to press out the pinion from the bearing and housing, change the shim stack and start again...

I took me 8 rounds to get where I wanted to be. Here is the path:

IMG_5352.webp


When you get close, small changes in the shim stack results in big changes in preload. When I hit 35 inch pounds at 92 thou, I was at the top of the range, and did not want to be that close. Adding just 1 thou to the shim stack dropped the preload to 15 - below the range. I went back down to 92 thou and hit 40. WTH? But when I pulled it apart, I double checked the stack and it was actually 92 thou - hence my change in the notes...:rolleyes:

Finally went back up to 92, but this time I used a different combination of shims to get to 92, and the mic showed a total stack of just a few tenths less than 92, which gave me 34 preload. That looked like the best I was going to get, so I called it good.

The final step is to tap in the pinion seal, install the yoke, torque down a new pinion locking nut, and the pinion is complete.

IMG_5353.webp


Now, it's finally pattern time...
 
The shims finally came in last night, and I did spend a little time getting the pinion dialed in. First up, I mic'd and marked the rest of the pinion preload shims:

View attachment 587638

The first setup at 88 thou locked the pinion bearing, indicated not nearly enough shim. So to bracket the results, I moved up to 101 thou.

This is the pinion bearing stack. The sleeve sits on the bearing, and the shims sit on the sleeve.

View attachment 587639

The pinion housing drops down onto the inner bearing, the outer bearing drops in, and finally the yoke and nut. The outer bearing is a press fit and is drawn down with the pinion nut using an impact. The yoke tool helps a lot here:

View attachment 587641

The final torque on the pinion nut is 250 foot pounds. Even with this long torque wrench, it takes some effort.

View attachment 587643

Finally, you test the pinion bearing preload using an inch pound dial torque wrench. On the 14 bolt, the pinion bearing preload target range is 20 - 35 inch pounds. At 88 thou of shims, the bearing bound. Now at 101 thou, the bearing preload was 0, but at least I had the bracket.

View attachment 587642

Then you start again. Back to the press to press out the pinion from the bearing and housing, change the shim stack and start again...

I took me 8 rounds to get where I wanted to be. Here is the path:

View attachment 587644

When you get close, small changes in the shim stack results in big changes in preload. When I hit 35 inch pounds at 92 thou, I was at the top of the range, and did not want to be that close. Adding just 1 thou to the shim stack dropped the preload to 15 - below the range. I went back down to 92 thou and hit 40. WTH? But when I pulled it apart, I double checked the stack and it was actually 92 thou - hence my change in the notes...:rolleyes:

Finally went back up to 92, but this time I used a different combination of shims to get to 92, and the mic showed a total stack of just a few tenths less than 92, which gave me 34 preload. That looked like the best I was going to get, so I called it good.

The final step is to tap in the pinion seal, install the yoke, torque down a new pinion locking nut, and the pinion is complete.

View attachment 587645

Now, it's finally pattern time...

I recently learned how to do this with my HP30. Also very finicky in the 0.001 or less range to get rotational toque spot on. In that case I got the pinion depth dialed in before using any pre-load shims. Here, its the reverse because your depth is controlled by shims under that 6 bolt flange, correct? Pretty cool set up in that you can do it on your bench.
When you are bracketing, do you walk up to full pinion nut torque slowly to prevent damaging the bears?
Did you use set up bearings or keep pressing on and off the finals?
 
Next up is to install a new straddle bearing (pinion support bearing) in the diff. It's a press fit, and I use a bearing race tool to knock it in:

IMG_5361.webp


In the 14 bolt, pinion depth is determined by the shim stack between the pinion support housing and the diff housing. To begin, I started with a shim stack of 88 thou - which was the stack from the previous setup. That's usually a good place to start.

IMG_5363.webp


The shims only fit on one way, and the difference is subtle:

IMG_5364.webp


To keep is straight, I mark the shims, the pinion housing, and the diff housing. The bolt holes on the pinion support housing will only line up with the shims and the diff housing one way, which ensures the oil galleries line up. This took me a few tries to jog my memory...:rolleyes:

It's a very tight fit, and the pinion support housing must be drawn in with the bolts - very carefully.

IMG_5365.webp


Here is the magic of the carrier bearing adjusters. I use a screwdriver with the end cut so that it engages with both sides of the adjuster. This is the piece that makes setting carrier bearing preload, and backlash, so quick and easy.

IMG_5366.webp


And in goes the carrier. Another nice thing about the 14 bolt setup is that you only have to lift the heavy carrier in once. The pinion housing? ... not so much. :)

IMG_5368.webp


To set the initial carrier bearing preload, you adjust the left carrier adjuster to move the ring gear until it contacts the pinion gear. You then adjust the right side adjuster until the adjuster contacts the right carrier bearing. This results in 0 backlash. To set the carrier bearing preload, you then adjust the right adjuster in toward the pinion gear three more notches. This sets the carrier bearing preload, and establishes the initial backlash.

The target backlash range for the 14 bolt is 3 - 12 thou, with a preferred range of 5 - 8 thou. My backlash measured at 4.5 thou, so a good place to start.

IMG_5369.webp
 
I recently learned how to do this with my HP30. Also very finicky in the 0.001 or less range to get rotational toque spot on. In that case I got the pinion depth dialed in before using any pre-load shims. Here, its the reverse because your depth is controlled by shims under that 6 bolt flange, correct? Pretty cool set up in that you can do it on your bench.
When you are bracketing, do you walk up to full pinion nut torque slowly to prevent damaging the bears?
Did you use set up bearings or keep pressing on and off the finals?

Definitely have to be careful on the first torque up of the pinion bearing. I got to where it had just bound the bearings and I stopped - no where near 250 ft pounds. Yes, you can damage your bears this way. :)

No setup bearings or races required on the 14 bolt. Although using a setup bearing for the outer bearing would keep you from having to press out the pinion each time. Not a big deal at all for me since I have to press right there. But it would save a little time and effort.
 
One final setup required before the first pattern. To get a good pattern, there needs to be significant resistance in the carrier/ring gear when turning the pinion. This is to create adequate pressure between the pinion gear and the ring gear to make reading the pattern easier. Billavista suggests this needs to be as high as 40-50 ft pounds at the pinion gear!

Well, I can't get quite that high, but this is how I do it. I use a double wrapped nylon strap around the carrier housing, and then a pry bar to lever the strap and create resistance to the carrier turning. I then clamp the pry bar in place. It very easy to release it and reinstall between setups.

IMG_5370.JPG


It's not 40-50 ft pounds, but is does get me up around 25, which seems to work well.
 
And after all that preamble, here is my first pattern at 88 thou shims, and 4.5 thou backlash:

IMG_5374.webp


IMG_5373.webp


Way, way to shallow. But a good start.

And here is the easy part with the 14 bolt. To change the pinion depth you unbolt the pinion carrier, and pull it with a puller since it is a press fit (this is the easiest way I have found).

IMG_5375.webp


Swap the pinion carrier shims, reinstall the pinion carrier, check the backlash, and take a new pattern. A lot easier than my old Dana 60 (and 44 for that matter).
 
I've learned a lot from @hosejockey61 and @Blackjack on gear setup. And one thing is to make big initial moves in the pinion depth to bracket the setup.

So I made a big move - I dropped 20 thou on the pinion carrier shims, down to 32 thou. The backlash measured 5 thou.

And here is that pattern:

IMG_5376.JPG


IMG_5377.JPG


Still too shallow, so I guess I need some improvement in my bracketing skills...:rolleyes:

Mike and Dan, now I can definitely use your input. Is my shallow assessment correct?
 
Gotta love the pinion shims on these. Does your axle weep 90wt around them? The 78 14bolt i put in my 70 k20 has always done that. Not enough to be anything but a slight oil stain but still an annoyance on an otherwise leak free axle