Re gear inquiry. | OVERLAND BOUND COMMUNITY

Re gear inquiry.

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Sec1127

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Hello everyone,

If I am in the wrong section of the site i apologize. I would like to know what gear set would be recommended for 2017 JKU Sport dana 30/dana 44? I currently have 35” tires & hope to eventually one day go up to 37”. I will travel long distance on paved/unpaved roads & will have weight of round tube style roof rack & RTT/Cargo inside & hitch receiver type cargo rack loaded/3 passengers.
Any info or opinions or suggestions are appreciated.
 

MazeVX

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Don't go to 37" with your stock front axle, it will only make it unreliable. 4.10 or 4.56 should be good for 35" depending on how often you drive to the mountains.
 
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PNW EXPLR

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I am not a jeep guy, but i would think that it may be wise to upgrade the front D30 to something stronger, then regear the rear to match. Probably similar cost.
 

MOAK

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Yikes- still that puny Dana 30 front axle? 33” tires max for that axle and that’s pushing it as you’ll be replacing ujoints about every 40-50 thousand miles if not sooner. Ask how I know. I did the jeep thing, I understand. However, if you insist on 35s then on up to 37s then 4:56s. 4:11 would not be worth your while. My 04 Rubicon had stock 4:11s. With racks gear etc, downshifting was a constant. Very rarely could you keep it in 5th gear for any length of time. The slightest grade or headwind required downshifting. This winter I’ll be re gearing our 80 from the stock 4:11s to 4:56s with 33” tires to get it back to stock performance. There’s a guy on the jeep forums, Jerry Brandsford that is a wealth of info about all things jeep. I’m pretty sure he would recommend stepping up to at least 4:88s if not 5:13s for 37” tires. I gotta ask- why such big tires? To what end? Tires that size will make any overlanding rig extremely unreliable, unless you have multiple thousands of dollars for all sorts of driveline and suspension upgrades, I mean thousands upon thousands upon thousands. Just curious ..
 

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I have seen a built Dana 30 last under rigs with 35" and 37" tires but they definitely need a truss at the very least. Also because of the ring gear size I wouldn't go any larger than 4.88 or even a 4.56 to be on the safe side to keep enough tooth contact to keep it strong enough to not explode as soon as you give it gas in 4 lo ona technical section. And I definitely would be gentle with it still.
I run JK Rubicon axles in my LJ with 4.88s and 37s but I kinda wish I went 5.13s. My rear axle is trusted and I run a 3 link fron, upper triangulated 4 link rear, 6" springs, outboarfef the rear shocks .... and the tires still rub from time to time, and I have broke stub shafts and ujoints in the front.
It's not my daily driver and it's a pig on fuel but it hasn't stopped me from getting anywhere I point it lol.
20210828_094116.jpgIMG_5179-1.jpg20210814_165800.jpg
 
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MOAK

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I have seen a built Dana 30 last under rigs with 35" and 37" tires but they definitely need a truss at the very least. Also because of the ring gear size I wouldn't go any larger than 4.88 or even a 4.56 to be on the safe side to keep enough tooth contact to keep it strong enough to not explode as soon as you give it gas in 4 lo ona technical section. And I definitely would be gentle with it still.
I run JK Rubicon axles in my LJ with 4.88s and 37s but I kinda wish I went 5.13s. My rear axle is trusted and I run a 3 link fron, upper triangulated 4 link rear, 6" springs, outboarfef the rear shocks .... and the tires still rub from time to time, and I have broke stub shafts and ujoints in the front.
It's not my daily driver and it's a pig on fuel but it hasn't stopped me from getting anywhere I point it lol.
View attachment 216563View attachment 216564View attachment 216565
You’ve made my point to the OP. Obviously you’ve dumped a crap ton of money into your beautiful LJ to make it into a trail worthy vehicle.
 

MazeVX

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Yikes- still that puny Dana 30 front axle? 33” tires max for that axle and that’s pushing it as you’ll be replacing ujoints about every 40-50 thousand miles if not sooner. Ask how I know. I did the jeep thing, I understand. However, if you insist on 35s then on up to 37s then 4:56s. 4:11 would not be worth your while. My 04 Rubicon had stock 4:11s. With racks gear etc, downshifting was a constant. Very rarely could you keep it in 5th gear for any length of time. The slightest grade or headwind required downshifting. This winter I’ll be re gearing our 80 from the stock 4:11s to 4:56s with 33” tires to get it back to stock performance. There’s a guy on the jeep forums, Jerry Brandsford that is a wealth of info about all things jeep. I’m pretty sure he would recommend stepping up to at least 4:88s if not 5:13s for 37” tires. I gotta ask- why such big tires? To what end? Tires that size will make any overlanding rig extremely unreliable, unless you have multiple thousands of dollars for all sorts of driveline and suspension upgrades, I mean thousands upon thousands upon thousands. Just curious ..
Well I have the same size ujoints in my d30 than the Rubicon has, the tube diameter and wall thickness is the same as with the d44 so the only thing different is the housing/ringgear size.
The stock 44 isn't that much stronger and I wouldn't worry going to 35" on a d30 with reasonable rim offset and a bit of driving with brain, for overlanding purposes, should be okay.
Unfortunately we don't know what gearing he has nor do we know what he wants to do with his jeep.
But for 37 I definitely recommend aftermarket front axle and trussed rear.
 

MOAK

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Well I have the same size ujoints in my d30 than the Rubicon has, the tube diameter and wall thickness is the same as with the d44 so the only thing different is the housing/ringgear size.
The stock 44 isn't that much stronger and I wouldn't worry going to 35" on a d30 with reasonable rim offset and a bit of driving with brain, for overlanding purposes, should be okay.
Unfortunately we don't know what gearing he has nor do we know what he wants to do with his jeep.
But for 37 I definitely recommend aftermarket front axle and trussed rear.
Yes, that was the downfall of that 44 front axle, I was replacing u joints as a matter of maintenance. The factories went out at 45,000 miles, and the blue ones, can’t remember the brand, went out at 80,000 miles. I was running 255/85/16s (33”) on stock rims. The factory suspension bushings lasted about the same, eventually swapped everything out with OME bushings.
 
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smritte

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Yes, that was the downfall of that 44 front axle, I was replacing u joints as a matter of maintenance.
That's why I went with RCV axles. Dont even ask how many mods I had. Should have done a 60 so I could run 37's. Even though I run them on my Cruiser, I'm glad I downsized my tires from 35's back to 32's.
 
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Well I have the same size ujoints in my d30 than the Rubicon has, the tube diameter and wall thickness is the same as with the d44 so the only thing different is the housing/ringgear size.
The stock 44 isn't that much stronger and I wouldn't worry going to 35" on a d30 with reasonable rim offset and a bit of driving with brain, for overlanding purposes, should be okay.
Unfortunately we don't know what gearing he has nor do we know what he wants to do with his jeep.
But for 37 I definitely recommend aftermarket front axle and trussed rear.
In a tj the ujojnts are the same from Rubicon to other models which should be a Spicer 5-760x ujoint.
With JKs the lower models come with the 5-760x joints but the Rubicon uses a 5-7166x joint. For some reason they did throw some variations in there for seemingly no reason and you can get a Sahara or sport or whatever er with those 5-7166x joints in it but most run the smaller 760xs
That and the shafts themselves are thinner so a truss helps to keep the axle from "flexing" and the straighter that shaft stays the stronger it will be.
Just my 2 cents.
By the way I am not disagreeing with you at all lol.
 
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MazeVX

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In a tj the ujojnts are the same from Rubicon to other models which should be a Spicer 5-760x ujoint.
With JKs the lower models come with the 5-760x joints but the Rubicon uses a 5-7166x joint. For some reason they did throw some variations in there for seemingly no reason and you can get a Sahara or sport or whatever er with those 5-7166x joints in it but most run the smaller 760xs
That and the shafts themselves are thinner so a truss helps to keep the axle from "flexing" and the straighter that shaft stays the stronger it will be.
Just my 2 cents.
By the way I am not disagreeing with you at all lol.
Yes I ordered the smaller ones because there was no reason I should have the bigger ones, as we replaced the ball joints I decided to replace the ujonts as well because they had about 100000km on them. They were ok ish given the water and salt they had seen but I'm seem to have bent a tube or inner c somewhere along the way and... So from my experience the tubes are the biggest concern that I have have.
Oh and I have the diesel torque pulling on them...
 
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Sec1127

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Thank you all for your input and suggestions & experiences. It is appreciated very much. Live in florida currently & will be riding different terrains & eventually in different states and areas in states i visit so that is why i ask for input with gearing.
 

RGILL

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My two cents the JK DANA 30 housing is also weak. The housing fails where the tube inserts into the housing. The short tube tends not to bend but the area where the tube inserts into the housing gets egg shaped. It is a tough area to reinforce. The tube sleeve kits do not reinforce this area. We have seen this area fail on several desert racing prepped rigs. I know that is an extreme environment but that is the area we see fail.
 
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