DIY Gear Swap - Step by Step Pic's - Rubicon 4.88

[chevymitchell]

Ok, adding back in pinion shim was causing the carrier to contact the pinion head and freeze up the diff. That took a while to figure out. Time to pound out the pinion race and try reducing the shim to see if I can get an acceptable pattern that clears the carrier.

That sounds very wrong. Adding in .040” is locking up the diff? Locking up the diff is likely backlash. Can you share a video explaining what’s happening or showing what’s being done? Triple check that the races are pounded in all the way and the pinion bearing is on all the way. Also, where are you applying the shims? Thanks man.

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[Some Random Guy]

That sounds very wrong. Adding in .040” is locking up the diff? Locking up the diff is likely backlash. Can you share a video explaining what’s happening or showing what’s being done? Triple check that the races are pounded in all the way and the pinion bearing is on all the way. Also, where are you applying the shims? Thanks man.

Dropping shim got me where I needed to be. Pinion shims were between the head bearing race and the case.
New patterns (with new compound):

Backlash is now 4 thou, PTR is 16, TTR is 26.
So first setup I used pinion head depth and setup with no shim. Second setup was too much shim leading to contact with the carrier. Third was just right. I used feeler gauges on all 3 to verify I had the races fully seated.
Edit: test run all quiet. Tomorrow I’ll get it up to 50 on the way to/from work. Fingers crossed.

 

[word302]

Ok, adding back in pinion shim was causing the carrier to contact the pinion head and freeze up the diff. That took a while to figure out. Time to pound out the pinion race and try reducing the shim to see if I can get an acceptable pattern that clears the carrier.

Are you sure that race is seating completely? That bit me the first run.

 

[word302]

Dropping shim got me where I needed to be. Pinion shims were between the head bearing race and the case.
New patterns (with new compound):

Backlash is now 4 thou, PTR is 16, TTR is 26.
So first setup I used pinion head depth and setup with no shim. Second setup was too much shim leading to contact with the carrier. Third was just right. I used feeler gauges on all 3 to verify I had the races fully seated.
Edit: test run all quiet. Tomorrow I’ll get it up to 50 on the way to/from work. Fingers crossed.

What are you at for pinion shim? I’m still afraid something isn’t seated. You’re not going to be able to get in there with a feeler gauge, especially if it’s only seated on one side. That still looks pretty shallow. Did you thin the paint/put lots of drag on the gears as you ran the pattern? Pattern isn’t very easy to read. No noise before break-in doesn’t mean no noise down the road. If you are running with 0 pinion shim something is waaaaaaay off.

 

[Some Random Guy]

What are you at for pinion shim? I’m still afraid something isn’t seated. You’re not going to be able to get in there with a feeler gauge, especially if it’s only seated on one side. That still looks pretty shallow. Did you thin the paint/put lots of drag on the gears as you ran the pattern? Pattern isn’t very easy to read. No noise before break-in doesn’t mean no noise down the road. If you are running with 0 pinion shim something is waaaaaaay off.

No, I'm running shim now. My blue patterns were from no shim using only pinion head depth measurements as my starting point. My 4.88 head is almost .10" deeper than my stock head. I think I ended up around .025" for final shim on yellow pattern, but didn't measure.
I do have some coast side noise at highway speed, but I suspect my low-side-of-spec PTR is to blame. I'll probably pop the driveshaft and hand-tighten the pinion nut 2-3 degrees with a breaker bar. It sounds like the 2 failures I had from the shop, just a lot quieter. I can only hear it with the radio off and the blower on low when at speeds over 55 mph.

Long version of frozen diff with too much pinion shim was that the first time I got it set up with good backlash (.004") and PTR of 18, TTR around 28. When I went to run a pattern the diff froze once it had rotated a bit and wouldn't move by hand from either inside the carrier or by turning the pinion (which had just had a drill on it). I played with carrier shim 3-4 times after that and sometimes the carrier would go in and allow me to get readings, other times it would freeze upon tightening the bearing caps. What pissed me off for one night is when I had a backlash of .002" and REMOVED large side carrier shim, then put the carrier back in and it froze. Totally illogical. The next day it occurred to me contact with the pinion head might be causing it to freeze up. Pulled carrier, and there were marks on it next to the openings for the spider gears. I'm assuming that was the pinion head, because then I pounded out the pinion and head bearing race again, dropped shim, re-assembled, and everything went smooth from there.

Now, when you say shallow do you mean the pattern is too close to the carrier (toe?) or not far enough down into the root of the ring gear? I'm not real good at the vocab since I try to avoid this job.

 

[Chance_P]

Any good articles or write ups for swapping a flange/yoke on our axles without messing things up?

 

[chevymitchell]

Any good articles or write ups for swapping a flange/yoke on our axles without messing things up?

Remove flange.

Install new flange until there’s no lateral or any movement of the flange. Once you reach this point stop.

You’re done.

 

[Chance_P]

Remove flange.

Install new flange until there’s no lateral or any movement of the flange. Once you reach this point stop.

You’re done.

Thanks. Seems too easy.

 

[word302]

No, I'm running shim now. My blue patterns were from no shim using only pinion head depth measurements as my starting point. My 4.88 head is almost .10" deeper than my stock head. I think I ended up around .025" for final shim on yellow pattern, but didn't measure.
I do have some coast side noise at highway speed, but I suspect my low-side-of-spec PTR is to blame. I'll probably pop the driveshaft and hand-tighten the pinion nut 2-3 degrees with a breaker bar. It sounds like the 2 failures I had from the shop, just a lot quieter. I can only hear it with the radio off and the blower on low when at speeds over 55 mph.

Long version of frozen diff with too much pinion shim was that the first time I got it set up with good backlash (.004") and PTR of 18, TTR around 28. When I went to run a pattern the diff froze once it had rotated a bit and wouldn't move by hand from either inside the carrier or by turning the pinion (which had just had a drill on it). I played with carrier shim 3-4 times after that and sometimes the carrier would go in and allow me to get readings, other times it would freeze upon tightening the bearing caps. What pissed me off for one night is when I had a backlash of .002" and REMOVED large side carrier shim, then put the carrier back in and it froze. Totally illogical. The next day it occurred to me contact with the pinion head might be causing it to freeze up. Pulled carrier, and there were marks on it next to the openings for the spider gears. I'm assuming that was the pinion head, because then I pounded out the pinion and head bearing race again, dropped shim, re-assembled, and everything went smooth from there.

Now, when you say shallow do you mean the pattern is too close to the carrier (toe?) or not far enough down into the root of the ring gear? I'm not real good at the vocab since I try to avoid this job.

You’re close. You see how there’s a flat line at the root of the teeth? That means shallow, you need another .003-.005” pinion shim. I’m really surprised you couldn’t get rotation with .040”. That tells me something ain’t right. My 5.13s setup within .003” of my 4.10s.

 

[Some Random Guy]

You’re close. You see how there’s a flat line at the root of the teeth? That means shallow, you need another .003-.005” pinion shim. I’m really surprised you couldn’t get rotation with .040”. That tells me something ain’t right. My 5.13s setup within .003” of my 4.10s.

My rigs are all cursed, lol. Just needs to survive until the 60 goes in the rear.
If the pinion tightening doesn’t solve the whine I’ll consider tearing it all down to add more pinion shim. I have 1 crush sleeve left, wish I had an extra pinion nut though. I think that low of an amount might fit without contact.

 

[word302]

My rigs are all cursed, lol. Just needs to survive until the 60 goes in the rear.
If the pinion tightening doesn’t solve the whine I’ll consider tearing it all down to add more pinion shim. I have 1 crush sleeve left, wish I had an extra pinion nut though. I think that low of an amount might fit without contact.

I’m just worried that something isn’t seated properly. .015” is a lot.

 

[Some Random Guy]

I’m just worried that something isn’t seated properly. .015” is a lot.

I was too, checked it multiple times by feel and by sound.
Case spreader arrives Wednesday, maybe the easier shim install will overcome my apathy. The whine is so faint that I’m the only one that can hear it even with everything off.

 

[chevymitchell]

I was too, checked it multiple times by feel and by sound.
Case spreader arrives Wednesday, maybe the easier shim install will overcome my apathy. The whine is so faint that I’m the only one that can hear it even with everything off.

If it’s that silent, then there’s nothing you can do about it. That’s likely just standard gear noise. Only way to get rid of that is to change out the R&P. If the pattern and all the other specs are good, then you don’t want to adjust outside of that for noise. The only way adjusting noise out works, is if the initial set-up wasn’t done right.

 

[Some Random Guy]

If it’s that silent, then there’s nothing you can do about it. That’s likely just standard gear noise. Only way to get rid of that is to change out the R&P. If the pattern and all the other specs are good, then you don’t want to adjust outside of that for noise. The only way adjusting noise out works, is if the initial set-up wasn’t done right.

Did you see the pattern in #287? Right now @word302 has me leaning towards pulling it apart once the spreader is here. My bigger concern is if the pattern isn't deep enough towards the root then I don't want to break it once I slap the bigger tires on. Noise is a secondary issue right now as long as it doesn't get worse. I haven't been on the interstate yet, that might drive me bananas. I think Wednesday is my interstate day.

 

[chevymitchell]

Did you see the pattern in #287? Right now @word302 has me leaning towards pulling it apart once the spreader is here. My bigger concern is if the pattern isn't deep enough towards the root then I don't want to break it once I slap the bigger tires on. Noise is a secondary issue right now as long as it doesn't get worse. I haven't been on the interstate yet, that might drive me bananas. I think Wednesday is my interstate day.

The pattern doesn’t necessarily have to be perfect in the middle. What you’re looking for, is the proper depth of the tooth engagement as the gears mesh. There’s an economy, neutral, and performance (some call it “competition”) setup for gearing. If you’re just inside of the center, then you’re setup closer to the performance side and that’s ok. The backlash setting helps make the proper mesh based on the pinion depth. Gears isn’t a 2 dimensional job where you set depth and backlash and you’re good. If you’re happy with the setup and it’s making noise, then try to shim it out. Just remember that the backlash setting is a trig problem and if you change one dimension with the pinion depth, then it’s a sloped solution for the backlash. They’re not proportional in change is what I’m getting at. The gears shouldn’t make any noise at all, so if you need to adjust it out, go for it. The pattern you sent doesn’t look bad. It’s just on the performance side of a setup.

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