Yukon Gear vs. Revolution Gear for a 14-bolt

[NashvilleTJ]

Those of you who follow my build thread know that I believe I've likely just smoked my second ring in pinion in my shaved 14-bolt. The last time I did this, the ring gear was fine, but the pinion gear - not so much:

It did not fail, but started making noise - just as it is now.

As noted I run a shaved 14-bolt, which requires the ring gear be milled down from 10.5" to a little over 10. Both sets of the failed R&P's have come from Yukon - because they sell a shaved version of the ring gear which makes it simple. This despite having some knowledge about the quality issues with Yukon gears in general.

Revolution Gear, with their Korean manufacturing, is widely regarded as the go to here on the forum. But, Revolution does not offer, not will they mill, a 14-bolt ring gear for a shaved setup. For me to run a Revolution gearset I will have to go through the hassle of getting the ring gear milled. I've not yet found a local place which will do it.

So here is my question: Is the improved quality of the Revolution gearset worth the extra milling hassle compared to just going the easy route with the Yukon gearset?

Also, does anyone think going to the Revolution pinion will stop the next failure? I do not, but I'm looking for any advantage.

I'm starting to think there is something to the whole "5:38's are weaker" thing, which I know has been discussed here and discounted. But, I'm now 2 for 2. I jokingly now refer to my rear axle as "The Sissy 14-Bolt."

Not to say these 14-bolt pinion gears are small, they certainly are not:

After smoking my old Pro-Rock 60 5 times, I built this 14-bolt thinking I was not going to be dealing with this any longer. Well, crap..

 

[Apparition]

How about USA standard. All 4 of my curries are running those gears.

https://www.usastandardgear.com/gad...MIkqyZrYWGkQMVHzjUAR0QHAs-EAAYASAAEgKia_D_BwE

 

[mrblaine]

Those of you who follow my build thread know that I believe I've likely just smoked my second ring in pinion in my shaved 14-bolt. The last time I did this, the ring gear was fine, but the pinion gear - not so much:

View attachment 656569

It did not fail, but started making noise - just as it is now.

As noted I run a shaved 14-bolt, which requires the ring gear be milled down from 10.5" to a little over 10. Both sets of the failed R&P's have come from Yukon - because they sell a shaved version of the ring gear which makes it simple. This despite having some knowledge about the quality issues with Yukon gears in general.

Revolution Gear, with their Korean manufacturing, is widely regarded as the go to here on the forum. But, Revolution does not offer, not will they mill, a 14-bolt ring gear for a shaved setup. For me to run a Revolution gearset I will have to go through the hassle of getting the ring gear milled. I've not yet found a local place which will do it.

So here is my question: Is the improved quality of the Revolution gearset worth the extra milling hassle compared to just going the easy route with the Yukon gearset?

Also, does anyone think going to the Revolution pinion will stop the next failure? I do not, but I'm looking for any advantage.

I'm starting to think there is something to the whole "5:38's are weaker" thing, which I know has been discussed here and discounted. But, I'm now 2 for 2. I jokingly now refer to my rear axle as "The Sissy 14-Bolt."

Not to say these 14-bolt pinion gears are small, they certainly are not:

View attachment 656575

After smoking my old Pro-Rock 60 5 times, I built this 14-bolt thinking I was not going to be dealing with this any longer. Well, crap..

If you are taking out the pinion, the problem is bad gears, bad set up, or similar. The pinion is inherently stronger than the ring by design and as a function of design. If there is enough deflection in the housing to allow the gear set to move out to the edges of the teeth and overload them to failure, I'd ponder how the shaving affects that.

 

[mrblaine]

How about USA standard. All 4 of my curries are running those gears.

https://www.usastandardgear.com/gad_source=1&ampgad_campaignid=21079233059&ampgbraid=0AAAAA9Z-IUhVLgAzjy9C2bFxioWFbqEaG&ampgclid=EAIaIQobChMIkqyZrYWGkQMVHzjUAR0QHAs-EAAYASAAEgKia_D_BwE

USA Standard is just an indicator of what box any given gear set ships in. There is no difference between them or any other gear set commonly sold by any gear shop except Revolution. I know that from the gent who came up with the concept of putting the same gears in two different boxes with different prices and warranties. Further, when any of them run out of gears, they trade back and forth with others so they can keep selling. It was common for Yukon to get gear sets from Superior and Superior to get gear sets from others and put them in their own boxes. Before Revolution, you can wind up with Circle K gear sets from just about any seller regardless of what pretty little logo was on the outside of the box. Revolution slowed that down a bunch since they are the US presence for the manufacturer.

 

[NashvilleTJ]

If you are taking out the pinion, the problem is bad gears, bad set up, or similar. The pinion is inherently stronger than the ring by design and as a function of design. If there is enough deflection in the housing to allow the gear set to move out to the edges of the teeth and overload them to failure, I'd ponder how the shaving affects that.

Do you think the Yukon gears could be contributing to the failure, and worth trying the Revolution?

Setup, well that was me both times. Certainly could have been some issue there, but I'm pretty meticulous. I'm a hack, but a meticulous hack. And the 14-bolt is a pretty easy setup as you know - no carrier bearing shims to fool with.

I do think it may be a deflection issue as you said. I've been looking around to see if anyone makes a load bolt setup for the 14-bolt.

And yeah, taking 250 thou off the outer ring gear diameter certainly doesn't make it stronger. When I pull this thing apart, I'm going to spend a bit of time looking to see if that impacts the pinion engagement with the ring gear.

 

[mrblaine]

Do you think the Yukon gears could be contributing to the failure, and worth trying the Revolution?

Setup, well that was me both times. Certainly could have been some issue there, but I'm pretty meticulous. I'm a hack, but a meticulous hack. And the 14-bolt is a pretty easy setup as you know - no carrier bearing shims to fool with.

I do think it may be a deflection issue as you said. I've been looking around to see if anyone makes a load bolt setup for the 14-bolt.

And yeah, taking 250 thou off the outer ring gear diameter certainly doesn't make it stronger. When I pull this thing apart, I'm going to spend a bit of time looking to see if that impacts the pinion engagement with the ring gear.

If the shaved ring gear diameter was anything that affected this, it would be the failure point, not the pinion. The failure implies that deflection is allowing the pressure to move the the outer edge of the tooth where it is the weakest. If it was a ratio issue, the whole tooth would shear off at the root or chunks out of it down to the root. The pinion teeth are stronger than the ring gear teeth. They shouldn't fail under load unless something is allowing them go out of pattern.

 

[hosejockey61]

I think you have answered your own question. If this is the second set of Yukon gears you have smoked, then I would look at a different manufacturer. Not brand name, but manufacturer. You know I'm a fan of Revolution, specifically because of the Circle K gears. I get help requests frequently regarding gear setups. 95% of the time it's people struggling with Yukon gears. They are just VERY inconsistent, especially since Covid hit.

 

[mrblaine]

They are just VERY inconsistent, especially since Covid hit.

While an appropriate observation, more than likely it is coincidental to them moving their gear production to China. The local gear shops I chat with report they will not even try to set up the Chinese gears from Yukon.

 

[NashvilleTJ]

Thanks Mike. Thanks Blaine. I'll order a set from Revolution and work on getting them milled.

I'm in no hurry. The last time this happened I think I ran those noisy gears for well over a year, maybe even two.

 

[mrblaine]

Thanks Mike. Thanks Blaine. I'll order a set from Revolution and work on getting them milled.

I'm in no hurry. The last time this happened I think I ran those noisy gears for well over a year, maybe even two.

I would spend some time researching these folks and see if their drag race versions are actually that. DR stuff is typically set up to be more forgiving to high torque loads in exchange for longevity. They are a "softer" gear that wears faster but with a bit more ductility so the teeth don't break as easily.
If you read their page on how they make the gears, they make all the right noises that shows they are intent on building something that is going to resist high levels of abuse.

https://www.crownracegears.com/gm_14_bolt_gears.html

 

[NashvilleTJ]

Thinking about this a bit, and chatting with Jeremy in a PM, triggered a thought.

Please check my math here:

On one hand it is highly unlikely that the shave had anything to do with the failure. I noted above that when I take it apart I was going to pay attention to the engagement of the gears. But I already know that - that's why you run a pattern during setup. If you have a pattern which bleeds off of the heel of the ring gear - where the shave would occur in this case - you've set it up incorrectly.

But the other possibility is that loosing that 250 thou at the outside diameter of the ring gear reduced its ability to resist deflection. So, maybe...

Damn sissy 14-bolt...

 

[NashvilleTJ]

I would spend some time researching these folks and see if their drag race versions are actually that. DR stuff is typically set up to be more forgiving to high torque loads in exchange for longevity. They are a "softer" gear that wears faster but with a bit more ductility so the teeth don't break as easily.
If you read their page on how they make the gears, they make all the right noises that shows they are intent on building something that is going to resist high levels of abuse.

https://www.crownracegears.com/gm_14_bolt_gears.html

Thanks Blaine. I will check them out as well. I would gladly trade off longevity for durability. In 20+ years I've only put about 30k on the rig.

 

[mrblaine]

Thanks Blaine. I will check them out as well. I would gladly trade off longevity for durability. In 20+ years I've only put about 30k on the rig.

If you are still trying to blame the deflection on a trimmed gear diameter and you are running the normal thickness gears, hop on the wrong side of the carrier break and get thick cut gears. It won't make any difference but at least then, you will stop blaming something that isn't at fault.

 

[gasiorv]

Not discounting your ear and past experience, but have you opened it up yet to determine it was actually the pinion failure again?

Beeker may be able to help you out with the shaving of the ring gear. Not sure but it would be worth touching base with him to see.

 

[NashvilleTJ]

Not discounting your ear and past experience, but have you opened it up yet to determine it was actually the pinion failure again?

Beeker may be able to help you out with the shaving of the ring gear. Not sure but it would be worth touching base with him to see.

I've not opened it up yet. But since I lived with the noise for so long the last time, I'm pretty sure I'm hearing the same thing. I'm going to order the gears and get them milled before bothering to pull it apart - I'd rather only do it once. If I do pull it apart and the gears are fine, I'll be OK with having a spare set.

I'll reach out to the Beekster.

 

[NashvilleTJ]

I would spend some time researching these folks and see if their drag race versions are actually that. DR stuff is typically set up to be more forgiving to high torque loads in exchange for longevity. They are a "softer" gear that wears faster but with a bit more ductility so the teeth don't break as easily.
If you read their page on how they make the gears, they make all the right noises that shows they are intent on building something that is going to resist high levels of abuse.

https://www.crownracegears.com/gm_14_bolt_gears.html

I did reach out to these folks. Filthy Motorsports in CO is a reseller for them. The shaved racing version of their 14-bolt ring and pinion is $1,300 - but the delivery was 8-12 weeks. A possibility if I decide I can wait that long.

 

[mrblaine]

I did reach out to these folks. Filthy Motorsports in CO is a reseller for them. The shaved racing version of their 14-bolt ring and pinion is $1,300 - but the delivery was 8-12 weeks. A possibility if I decide I can wait that long.

Did they understand the application and make all the right noises about their product being appropriate?

 

[NashvilleTJ]

Did they understand the application and make all the right noises about their product being appropriate?

The guy at Filthy wasn't able to add much to what is listed on the Crown site. He basically said the Crown R&P would work well for my rig - but didn't really describe why. Since I'm running and have some time, I plan to reach out directly to Crown and get a better understanding.

Well over double the cost of the Yukon or the Revolution gears, but if they don't fail that would be worth it to me. Still investigating.

 

[Lanzg]

The guy at Filthy wasn't able to add much to what is listed on the Crown site. He basically said the Crown R&P would work well for my rig - but didn't really describe why. Since I'm running and have some time, I plan to reach out directly to Crown and get a better understanding.

Well over double the cost of the Yukon or the Revolution gears, but if they don't fail that would be worth it to me. Still investigating.

Do they mention anywhere what the material of this race gear is? I had to go to race gears in my Orange car (9" based stuff, light buggy, lots of motor) eventually to stop breaking ring and pinions. We put lots of them in race cars so I wasn't concerned with wear after prepping the same gears year after year in them, my car was pre ran for years, but it's just a trail rig these days, set up is always close when I have it apart, and the softer 9310 material has fixed it for me.

Always amazed me what the race cars would put up with and keep going.

Maybe they will tell us what they are using, alot of info on what they are doing but not much on exactly what they are doing it on. Just to cryo and REM polish a regular R&P would put you in the 1000$ range.

Be curious what we learn, we build a ton of 14 bolts with off the shelf parts, I can't remember the last R&P failure, but Id love to find a legit alternative.

LG

 

[NashvilleTJ]

Did they understand the application and make all the right noises about their product being appropriate?

The guy at Filthy wasn't able to add much to what is listed on the Crown site. He basically said the Crown R&P would work well for my rig - but didn't really describe why. Since I'm running and have some time, I plan to reach out directly to Crown and get a better understanding.

Well over double the cost of the Yukon or the Revolution gears, but if they don't fail that would be worth it to me. Still investigating.

Well, I spoke to soon. I followed up with the Filthy Motorsports guy - and it tuns out he is the real deal. Ben Brazda - to whom I spoke - is the owner of Filthy Motorsports, and also the owner of Crown Race Gears. He builds a lot of gears setups for Ultra 4 racers, rock bouncers, drag racers, mud drag racers, desert racers, and the like. He certainly was able to demonstrate - at least to me - that he knows what he is talking about.

He spoke with me for quite a while on my issues. He believes my failures may likely be a setup issue, and that for an application like mine I should not be setting it up with a standard pattern that you would use for a GMC truck - which is what I did. He recommends - and does - a much deeper setup much closer to the root to allow for deflection which will invariably occur in high shock-load situations. He actually said that with a deeper setup, even the low-quality Yukon Chinese gears should hold up. He also recommended going with Revolution as another alternative, and that should be fine as well. When I told him I have pictures of my pattern, he suggested that I send them to him and he may be able to provide some insight.

He explained a lot about their processes and how they make their gear sets, as well as the slightly different approaches they take depending on the ultimate application. Desert racing is different than rock crawling and bouncing, etc.

He also said that a simpler solution may be to go down to a 4.88. Yup, he said it. 2 tooth engagement compared to a one tooth engagement for the 5.38's. The cheaper gears would even hold up better in that setup. This has been discussed on the forum often, and Blaine has weighed in as well, but this guy says the 5.38 setup is definitely a little weaker all other factors being consistent. But, the 5.38's can be made strong enough - given the right metallurgy, treatment, and especially setup. He says the vast majority of his Ultra-4 customers run 5.38's.

I asked him specifically about his cryo-processing, and how he avoids getting too brittle of an end result. He said, "Very good question..." which made me feel good. He then explained how it all works in a way that I understood as he was explaining it, but I certainly could not explain it to someone else. Again, he does sound like he knows his stuff, and has been doing this for a long time.

We talked at length about the shaving process he uses, and how they do it in a way which takes into account avoiding heat building, burring, etc. He says they spend about 8 hours to do it correctly. He asked if I knew how Yukon does it, and I responded that I did not, but he thought for the price they charge they probably throw is on a lathe and hack away at it - possibly destroying the heat treatment in the process. He said that was just a guess on his part, but it could result is a weaker gearset.

Ben also warrants his gears for 5 years assuming a proper setup - which he would help me get to and confirm. He also indicated that he could analyze my failed gearset if I sent them to him, and likely would be able to tell me why they failed. I may take him up on that.

All in all, I really enjoyed the conversation with Ben. Although he recommended several less expensive solutions that he thought would meet my needs, I ultimately decided to go with a set of his race gears. He also offered to work with me on the setup when the times comes.

He was not in his shop during our conversation, but he was going to check if they had anything on the shelf which might reduce the 8-12 week lead time.

It's gonna be expensive, but it appears this may be the best approach to providing the best chance to avoid this happening again.