Going to 4.88 or 5.13 for 37s?

[CarbonSteel]

I guess I am more confused now, than when I first posted this thread.

One of my main concerns and reasons for changing gears was to prevent damage to the transmission from running 37s.

Now I am hearing/reading, going to 4.88 or 5.13 increases the risk of them breaking.

So, are the stock 4.10s in my Rubicon more durable than 4.88s and or 5.13s?

Under the conditions for which a Dana 44 Advantek axle was designed to operate and perhaps even a bit past those limits a 4.10 ratio is no more stronger than a 5.38.

You do not see postings weekly or monthly about ring and pinion failures and the ones which are posted, there is almost always some extreme "something" that happened.

I have ran 4.10, 4.88, and 5.13 in my JLUR (probably one of the few who have) and I have as much confidence in the 5.13s as I did in the 4.10s.

You should not become mired down in "paralysis analysis" from multiple opinions. Do what suits you. Dana would not offer 5.13 and 5.38 ratios if they were THAT prone to failure.

Hell...had I listened to the "horror" stories posted here, I would not have even bought a Jeep. Internet amplification only happens en masse with bad information, not good.

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[kapk22]

Under the conditions for which a Dana 44 Advantek axle was designed to operate and perhaps even a bit past those limits a 4.10 ratio is no more stronger than a 5.38.

You do not see postings weekly or monthly about ring and pinion failures and the ones which are posted, there is almost always some extreme "something" that happened.

I have ran 4.10, 4.88, and 5.13 in my JLUR (probably one of the few who have) and I have as much confidence in the 5.13s as I did in the 4.10s.

You should not become mired down in "paralysis analysis" from multiple opinions. Do what suits you. Dana would not offer 5.13 and 5.38 ratios if they were THAT prone to failure.

Thank you for the reply/info.

 

[Rodeoflyer]

Here's something else to chew on lol

 

[At Risk Ute]

Couple of other highway benefits I’m seeing from 4.10 to 4.88 gears on 37s driving in the mountains... mpg has gone up (~3 mpg) and I’m abusing my tranny way less.

Felt bad for my tranny after driving my two stock XRs (4.56 gears on 35s).

Looking forward to Moab next week. YMMV.

 

[grimmjeeper]

It’s the opposite. The higher the number, the smaller/thinner the gears have to be to fit more theeth on the same circomference/size ring and pinion.

But, the stronger the Jeep pulls due to the demultiplication of gearing.

Partially. As the gear ratio number goes up, the pinion head gets smaller.

In this picture the 4.30 ratio is on the left, 5.38 on the right. Note the size of the pinion heads.

Both ring gears have 43 teeth and they are comparable in size.

If the pinion has the same number of teeth between ratios and the ring gear gets more teeth, the smaller pinion head means smaller teeth, which matches the more smaller teeth on the ring gear. And with more smaller teeth you get more teeth in contact which balances out the strengh loss in the teeth.

 

[av8or]

I concur with all who said 5.13 for 3.6, and 4.88 for 2.0. 2.0 has more low end torque and the 3.6 is a screamer. I’ve got 68k on 5.13s with lots of towing a 3,500 lbs camper and many trails and wouldn’t change a thing.

 

[LCW]

Just upgraded to 37s Friday. KO2s load range D. JLUR with 2.0. Still team 4.10 for now. Pretty flat here (MN). So far it’s been fine for daily driving. Seeing 8th even at 60. About 1600 at that speed.

Will probably run this way for a bit. Want to wheel it to see. But down the road when funds allow I’ll consider re-gearing.

 

[bobholthaus]

I have 4.56s on 37 KO2s, but I have the diesel and it’s torque. For this engine and tires, I think 4.56 is absolutely perfect. I know you didn’t ask; this is just for reference.

 

[XtremeRetard]

From Nitro Gear...

Gear strength

 

[J0E]

Under the conditions for which a Dana 44 Advantek axle was designed to operate and perhaps even a bit past those limits a 4.10 ratio is no more stronger than a 5.38.

You do not see postings weekly or monthly about ring and pinion failures and the ones which are posted, there is almost always some extreme "something" that happened.

I have ran 4.10, 4.88, and 5.13 in my JLUR (probably one of the few who have) and I have as much confidence in the 5.13s as I did in the 4.10s.

You should not become mired down in "paralysis analysis" from multiple opinions. Do what suits you. Dana would not offer 5.13 and 5.38 ratios if they were THAT prone to failure.

Hell...had I listened to the "horror" stories posted here, I would not have even bought a Jeep. Internet amplification only happens en masse with bad information, not good.

4.10 ratio is no more stronger than a 5.38.

That's wrong, defies physics and all the experts
Size Matters: The Ring Gear To Pinion Tooth Relationship - Even the commonly worshipped Dana Spicer Model 44 does not hold up well to tall tires and ratios in the 4.89 plus range due to its 8-1/2″ ring gear and short teeth.

A 4.10 gear set will have larger teeth and a higher tooth contact area than a 5.38 gear set, which means that it will be able to distribute load and torque more effectively across a larger surface area. This results in less stress on individual teeth and less likelihood of premature wear or failure.

The ring gear and pinion set with a 4.10 ratio have fewer teeth than a 5.38 set, but each tooth will be larger and stronger due to the smaller gear ratio. This means that the 4.10 gear set is more robust and able to handle more torque and horsepower without experiencing premature wear or failure.

On the other hand, the 5.38 gear ratio has more teeth on the ring gear and pinion, which reduces the size of each tooth, making them less robust.

5.38 teeth significantly smaller. The tooth contact area on a 5.38 gear set is smaller due to the increased number of teeth

My LJR is running 38x13.5R17 Nitto's on bead locks with RCV's in the front and chromoly in the rear, stock 4.10 gears. Right now the R&P is the weak link and no way I'm going to lower gears when I have more than enough torque with the 4:1 xfer case and auto in M1. I can climb vertical in M2. I could care less about hitting D8 on the highway. I've optimized for the trail, not the interstate.

I only crawl, never bounce. When I need more gear, I take my LJ with a ProRock60/80. It's got 5.38 gears but much bigger ring gears and it's actually not geared as low as my JLR due to the amazing AT.

 

[CarbonSteel]

4.10 ratio is no more stronger than a 5.38.

That's wrong, defies physics and all the experts
Size Matters: The Ring Gear To Pinion Tooth Relationship - Even the commonly worshipped Dana Spicer Model 44 does not hold up well to tall tires and ratios in the 4.89 plus range due to its 8-1/2″ ring gear and short teeth.

A 4.10 gear set will have larger teeth and a higher tooth contact area than a 5.38 gear set, which means that it will be able to distribute load and torque more effectively across a larger surface area. This results in less stress on individual teeth and less likelihood of premature wear or failure.

The ring gear and pinion set with a 4.10 ratio have fewer teeth than a 5.38 set, but each tooth will be larger and stronger due to the smaller gear ratio. This means that the 4.10 gear set is more robust and able to handle more torque and horsepower without experiencing premature wear or failure.

On the other hand, the 5.38 gear ratio has more teeth on the ring gear and pinion, which reduces the size of each tooth, making them less robust.

5.38 teeth significantly smaller. The tooth contact area on a 5.38 gear set is smaller due to the increased number of teeth

My LJR is running 38x13.5R17 Nitto's on bead locks with RCV's in the front and chromoly in the rear, stock 4.10 gears. Right now the R&P is the weak link and no way I'm going to lower gears when I have more than enough torque with the 4:1 xfer case and M1. I can climb vertical in M2. I could care less about hitting D8 on the highway.

Been argued into the ground too many times to count on this forum. Believe whatever you like and makes you feel good.

And next time quote my entire statement instead of taking it out of context.

 

[J0E]

Been argued into the ground too many times to count on this forum. Believe whatever you like and makes you feel good.

And next time quote my entire statement instead of taking it out of context.

I quoted your entire statement and added the absurd part again. Yes I agree, there's lots of misinformation on this forum. But this is simple physics and the experts have weighed in. 5.38 is significantly weaker than 4.10 in a D44.

 

[CarbonSteel]

I quoted your entire statement and added the absurd part again. Yes I agree, there's lots of misinformation on this forum. But this is simple physics and the experts have weighed in. 5.38 is significantly weaker than 4.10 in a D44.

No, you didn't:

Under the conditions for which a Dana 44 Advantek axle was designed to operate and perhaps even a bit past those limits a 4.10 ratio is no more stronger than a 5.38.

Nothing absurd here.

Do show what "experts" can disprove the part that is bolded.

 

[Vinman]

While 5.38’s may be weaker than 4.10’s, the question that should be asked is are the 5.38’s strong enough?

I have 5.13’s in my 3.6 e-torque auto 4 door Rubicon running 37’ KO2’s and couldn’t be happier.
Loaded for camping I’m typically about 6,000 lbs and it still pulls decent at 6,000 ft elevation.

 

[grimmjeeper]

Yes I agree, there's lots of misinformation on this forum.

The irony of this statement is overwhelming coming from you. Every few months you show up and repeat the same easily disproven garbage.

Yes, size does matter. When you run 40" tires or bigger on an axle not designed to handle them, you're pushing your luck. When you push a lot of torque through an axle not designed to handle it, you're pushing your luck. It doesn't matter if you're running 4.10s or 5.38s. Thrashing on a 1/2 ton axle with big power and big tires will break it eventually no matter what ratio you run.

That's why people go with tons. Those axles are bigger and stronger. They hold up to abuse better because they're built to handle it.

Just because a pinion has more teeth doesn't make it stronger. You can easily see for yourself. Take multiple gear sets side by side. Put the pinion on the ring gear and see how many teeth are actually in contact at any time. You'll easily be able to see that the same number of teeth are in contact. All you have to do is look up a few posts in this very page to see the obvious evidence of this.

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