Re-gear

[Redjeep8901]

Ok looking for some feedback on this one. I have a 2009 jk with 35's, I plan on keeping this jeep for as long as humanly possible. I got the jeep with the tow package and am currently running 3.73's. My next set of tires will be 37's (I just got the 35's so this is a while down the road) but in the mean time my next big purchase I am saving for are e-lockers. The people I am talking to said I am going to want to run higher gears because it's going to feel like a dog with 37's on it......I don't have a problem right now with the 35's plenty of power and driving like Mrs. Daisy is in the jeep , but should I be looking to re gear before I start to think about lockers? If I do re-gear I am only thinking 4.10's as I still want this to have good street manners (hence the selectable lockers). In the past I ran a stock axle TJ with a Dana 35 and 35's waiting for it to break and It never did, these same people told me I couldn't do that, but I did (I know I was pushing it though) are they just trying to sell me stuff I don't need, is it time to find a new shop to buy my parts (do most work myself), or is a re-gear necessary? I don't have a ton of money to dump into my jeep (2year old, and 120 year old house), but am willing to save and spend in the correct places. Thanks for any info......

[RalphTomaccio]

I am not, by any means, an expert on this subject, but am learning as I slowly build my JKU, also with 3.73's. Larger tires is high on my list of "next mods" and would like to avoid having to regear. From what I have learned, there are probably a lot of people that are going to tell you you should have regeared when you went to 35's. I would say that going to 37's, yes, definitely regear.

[Hoodoo Man]

It would be a waste of money to go to 4.10 from 3.73.. A 4:88 or 5.13 would be recommended for 37s, new gears won't hurt street manners at all, it will help keep the jeep moving down the highway with ease.. IIRC the JKs all use the same carrier so its not like the TJ where there is a carrier break and all but if you can afford to do it all at once it makes sense to do the lockers with the re-gear... In the end its your jeep and your money but the cost of going to 4.10s wont be worth it for the benefit you get...

[Spudcannons]

you would want 5.13 with the 3.8l to have it accelerate at a normal pace. I'm running 4.88 with 37s but I have a 2013 with the 3.6l.

[ASauer17]

I ran 35s on my TJ with a d44 for maybe... 3 years. I regeared to 4.88

[Yipjeep]

The 3.21s in the JKs use a different carrier; however, 3.73 and up use the same carrier. I thought the same thing as Ralph. Surprised you didn't need to regear for the 35's. I've heard many complain about the pre-2012 JKs being bogged down with larger tires. Seems those pre-2012 opt to go to 4.88 or 5.13, but that discussion is when talking about 35s. I'd also be concerned about the front needing sleeves and gussets to support the 37's. More experienced folks can chime in on the importance if JK is just crawling around a mall or bouncing around rocks.

[schwalby]

Go 4.88. We just got 37s on our 2015 and it does just fine on the street, pretty easy to go too fast actually. And when coming off the line I have to be careful to not give it too much gas.

You can also use the same carrier when going to 4.88s, anything after that does need a new carrier.

[Redjeep8901]

Forgive me for sounding uneducated, never dealt with lockers before, but when adding a locker does that not replace the carrier?

[Redjeep8901]

Now I am thinking 4.88...... E lockers and 30 spline front shafts...... Someone told me to try to find a used rubicon 44, but a built 30 has the same or more strength than a rubicon 44 at less cost

[RalphTomaccio]

Here's a chart you may find useful:

[schwalby]

delete

[schwalby]

Forgive me for sounding uneducated, never dealt with lockers before, but when adding a locker does that not replace the carrier?

A locker does replace the carrier but someone mentioned it so I thought I would confirm. Sorry for any confusion.

Now I am thinking 4.88...... E lockers and 30 spline front shafts...... Someone told me to try to find a used rubicon 44, but a built 30 has the same or more strength than a rubicon 44 at less cost

Personally I wouldn't put any money into a D30. You can make them stronger but they are still a weaker axle from the start. I have done some research and a lot of people of wheeled 37s with a D30 but you have to be careful with it. On our JK and our TJ I hope to go to D44s before locking.

Others can correct me but I believe adding a locker to any axle can put more stress on it also.

[Kurt]

Others can correct me but I believe adding a locker to any axle can put more stress on it also.

Absolutely correct
Without a locker (or a locker that is unlocked) the torque on the axle is limited to the tire with the LEAST traction. The toque is split 50/50 between the two tires (and axle shafts, u-joints, etc)

When the axle is locked all the torque can be on the tire with the MOST traction. The result can be that ALL the torque is applied to a single tire and it's axle shaft and u-joint are under 100% of the applied torque. Much more stress (torque) is possible on the axle components when locked.

[schwalby]

WooHoo I got it right!!

[DDewar53]

In my opinion - while a locker puts more stress on axle internals, open diffs are easier to break. This is because most axles break when the wheel starts spinning, the axle hops a little, then the spinning wheel suddenly gets traction. It stops - with all of that power still going to it, and that's how axle internals break. Less chance of spinning and wheel hopping with a locked axle, at least in my experience.

before the flames start - Tthis is my opinion based on my experience. YMMV