Axle Help

c_bronson

c_bronson

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Joined
Jan 23, 2019
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81
Location
Amarillo, Texas
I just need some quick verifications to make sure I provide my installer with exactly what I want. I've spent so long going through this forum I'm starting to get things criss crossed and confused.

I have a 99 Jeep TJ with Dana 30 front and Dana 35 rear axles. I'm planning for 35s in the near future and am currently on 33s. No larger than 35s ever.

I want to upgrade the rear axle with the following (my installer uses exclusively Nitro gears so Revolution isn't an option):
  1. Nitro 1541H steel and 4340 alloy & chromium and molybdenum alloy axles (chromoly) in 30 spline
  2. ARB Air Locker
  3. 4.88 Gears
The front axle will get the following:
  1. Chromoly shafts
  2. 4.88 gears
  3. ARB Air Locker
Big question, I was going to go with 30 spline front shafts. I don't want to deal with any more axle upgrades in the future. I'm a one and done kind of guy and I've been holding off on this for over a decade (money being the biggest reason). Is there a down side to 30 spline that would make it smart not to?
 
c_bronson said:
I just need some quick verifications to make sure I provide my installer with exactly what I want. I've spent so long going through this forum I'm starting to get things criss crossed and confused.

I have a 99 Jeep TJ with Dana 30 front and Dana 35 rear axles. I'm planning for 35s in the near future and am currently on 33s. No larger than 35s ever.

I want to upgrade the rear axle with the following (my installer uses exclusively Nitro gears so Revolution isn't an option):
  1. Nitro 1541H steel and 4340 alloy & chromium and molybdenum alloy axles (chromoly) in 30 spline
  2. ARB Air Locker
  3. 4.88 Gears
The front axle will get the following:
  1. Chromoly shafts
  2. 4.88 gears
  3. ARB Air Locker
Big question, I was going to go with 30 spline front shafts. I don't want to deal with any more axle upgrades in the future. I'm a one and done kind of guy and I've been holding off on this for over a decade (money being the biggest reason). Is there a down side to 30 spline that would make it smart not to?
Click to expand...

Stick with the 27 spline chromos and carrier
 
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It also seems more common for a buddy to have 27 splines in the Dana 30 so you can bum parts if needed or find them relatively easier locally.
 
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tworley said:
The Dana 30 can handle 35s easily with chromo shafts. 30 spline will require a 30 spline carrier and different hubs (more $$).
Click to expand...
I get what you're saying and that makes sense. My last question so I'm 100% clear, I'm planning on an ARB locker up front. So that would take care of the 30 spline carrier. I just want to make quite sure that I'm not losing any performance or benefits from not going 30 spline up front. Otherwise I'll follow what you said and go 27.
Rob L. said:
It also seems more common for a buddy to have 27 splines in the Dana 30 so you can bum parts if needed or find them relatively easier locally.
Click to expand...
This makes sense. I didn't think about more people having 27 spline on the trail.
 
c_bronson said:
I want to upgrade the rear axle with the following (my installer uses exclusively Nitro gears so Revolution isn't an option):
  1. Nitro 1541H steel and 4340 alloy & chromium and molybdenum alloy axles (chromoly) in 30 spline
Click to expand...
1541h and 4340 are not the same
you want 1541h in Dana 35
 
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c_bronson said:
I get what you're saying and that makes sense. My last question so I'm 100% clear, I'm planning on an ARB locker up front. So that would take care of the 30 spline carrier. I just want to make quite sure that I'm not losing any performance or benefits from not going 30 spline up front. Otherwise I'll follow what you said and go 27.

This makes sense. I didn't think about more people having 27 spline on the trail.
Click to expand...

No loss sticking with 27. But if you already have the 30 spline ARB, then you have to use a 30 spline axle shaft. Double check the carrier specs. I've been using an ARB for several years now with 27 spline 4340 RG&A shafts. We play hard on the weekends and haven't had any issues
 
eastbloc said:
1541h and 4340 are not the same
you want 1541h in Dana 35
Click to expand...
Thanks for catching that, I just copied the description from Nitro and wasn't paying attention. Why is it we want the 1541h in the rear? Also, I can't really tell from the description here which one, 1541h or 4340, actually comes with the kit. Might have to call them.
tworley said:
No loss sticking with 27. But if you already have the 30 spline ARB, then you have to use a 30 spline axle shaft. Double check the carrier specs. I've been using an ARB for several years now with 27 spline 4340 RG&A shafts. We play hard on the weekends and haven't had any issues
Click to expand...
Okay perfect, I'll go with the 27 spline then. I haven't ordered the parts yet so I can easily switch the ARB locker to the 27 spline. Thanks a lot for your help.
 
Just to be sure and summarize what you need. You need 30 spline (not 27) 1541H shafts for your rear Dana 35 to handle 35" tires.

For the front axle, 4340 27 spline shafts are fine with 35's.
 
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c_bronson said:
Thanks for catching that, I just copied the description from Nitro and wasn't paying attention. Why is it we want the 1541h in the rear? Also, I can't really tell from the description here which one, 1541h or 4340, actually comes with the kit. Might have to call them.

Okay perfect, I'll go with the 27 spline then. I haven't ordered the parts yet so I can easily switch the ARB locker to the 27 spline. Thanks a lot for your help.
Click to expand...
4340 doesn't have the hardened surface a 1541 has and the bearing will wear a groove into 4340 rear shafts on a Dana 35. 4340 is fine up front
 
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Jerry Bransford said:
Just to be sure and summarize what you need. You need 30 spline (not 27) 1541H shafts for your rear Dana 35 to handle 35" tires.

For the front axle, 4340 27 spline shafts are fine with 35's.
Click to expand...
Jerry, thanks for this. Was getting a little lost on what I needed in which axles.
tworley said:
4340 doesn't have the hardened surface a 1541 has and the bearing will wear a groove into 4340 rear shafts on a Dana 35. 4340 is fine up front
Click to expand...
Okay, that makes sense. I called and verified that the 35 Kit is made from the 1541H so we should be good to go! Should have ordered this before steel prices sky rocketed. Oh well, live and learn.
 
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tworley said:
4340 doesn't have the hardened surface a 1541 has and the bearing will wear a groove into 4340 rear shafts on a Dana 35. 4340 is fine up front
Click to expand...
@tworley is right on. To state it a little differently:
The axle shaft on a Dana35 serves as a bearing surface and, as such, needs to be hardened to do it's job.
The Dana30 has a dedicated outer bearing in the hub assembly so the shaft doesn't need to be hardened.
 
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Jerry Bransford said:
Some of what was said was getting very confusing to me too which is why I summarized it for you.
Click to expand...
Jerry, since you went ahead and chimed in, I'll verify one last thing here. In either one of these setups (front and rear), what is the weak link? I want to keep the weak link away from being the ring and pinion.
 
c_bronson said:
Jerry, since you went ahead and chimed in, I'll verify one last thing here. In either one of these setups (front and rear), what is the weak link? I want to keep the weak link away from being the ring and pinion.
Click to expand...
With 35's, the weak link is definitely stock Dana 35 axle shafts. Don't worry about the R&P gears with 35's even in the Dana 35.
 
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tworley said:
The Dana 30 can handle 35s easily with chromo shafts. 30 spline will require a 30 spline carrier and different hubs (more $$).
Click to expand...
You don't need different hubs for 30 spline shafts. The 30 splines are inner only. There was one company, Alloy USA I believe, who sold 30 spline unit bearings and stubs, but there was no reason to ever choose those.

30 spline typically costs the exact same as 27, unless you aren't installing a locker or CM shafts and want to keep the factory 27 spline carrier. If you are going to a locker and CM shafts, usually it's the same cost (30 vs 27) on both lockers and shafts, so there is no real cost increase if you're going to a locker and CM shafts no matter what.

As to whether or not someone needs 30 splines or not, that's a different story really. Most probably don't, but it doesn't hurt to have them. Harder to have trail spares though, so that is a downside to them.
 
c_bronson said:
So even if I upgrade the Dana 35 shafts to the 1541H, the R&P gears are not the weak member?
Click to expand...
Stop worrying about the R&P gears, they're not an issue even after installing a Super 35 kit. Those gears driving Super 35 axles with 35's have survived trails in Johnson Valley that would make 99% of this forum's membership faint.
 
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c_bronson said:
So even if I upgrade the Dana 35 shafts to the 1541H, the R&P gears are not the weak member?
Click to expand...
You'll be fine. It doesn't really matter what becomes the "weakest member", what really matters is that the overall axle is much stronger (pretty much strong enough for 99%) to the point where you really shouldn't have strength concerns overall. If you look at Dana 35 gears vs Dana 44 gears, there is no real difference in them. The Dana 44 stuff looks bigger at first but when you start comparing the details like tooth profile and such, there is barely any difference. Plus, tons of super 35's over the years have proved R&P to be a non issue.

Keep in mind, you can break anything, so really nothing guarantees no breakages no matter what. The S35 is a great kit for what it is.
 
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