[maddog2020]

What's the advantage of getting the 3.73 axle? What's the standard axle and what's better about the 3.73?

 

[trainman]

The 3.21 gearing is standard on the Sport and Sahara models, plus a few other special editions models. The 3.73 is standard on models like the Willys and Rubicon models, most buyers liking as it works better with larger tires and has better off road power and performance. Most Wranglers are sent from the factory with the 3.21 gears as most Jeep are not driven off road where the lower gearing is needed, plus most street Wranglers their new owners never ask about what gearing is in their vehicle, they just want to drive a Jeep. That being said, get a Jeep equipped how you are going to use it, most people on this forum are into some off road and want to up grade their Jeep in time, but if you just want a Jeep and dirt roads are probably as off road as you will get, go with the stock gearing it will work just fine. Like myself, I ordered a Willys and I will probably never use it to its full potential, but I like the idea of having the lower gears and Posi-Loc rear end, just in case I go crazy and become a real off road guy, ok at 72 probably not.

trainman

 

[Dew]

Also, you might be confusing Gearing with Axles. Stock Wrangler comes with 3.21 gearing and D30 Front Axle/D44 Rear Axle. Heres an article with a nice rundown.

Dana 30 vs Dana 44: Whats The Difference?

 

[WillyD]

We have both worlds, the wife's JKU has the 3.21s (open) in it and my ex-Willys had 3.73s (LSD) but is now running 4.56s (truetracs).

The JKU is our trip vehicle. Lil better gas mileage, but is does not like towing the heavier stuff especially with the hills around here. It is running the stock size 18"s. For my JK, I have stepped up to 35s and tow a 17-1900# camper. She gets the 1250# trailer and ATV.

In the future if you are going to go with taller tires, the only difference is that with the 3.21s you will have to get a 3.73 carrier (about $80) over the cost of regearing.

I lied to myself when I bought my JK and made the infamous statement "I won't be lifting and bigger tires". If I was truthful to myself, I would have gotten a sport with 3.21s and saved the "upgrade" price. With the Dana 30 upfront, the general consensus is that 35s is going to be the max and that a Dana 44 (Rubi) for 37s.

The questions that need to be answered are: Are you going to tow, Are you going to go larger tires, How much and level of off-roading are you going to be doing.

A regear will cost about $1400. Mine was $2200 because of the F&R TrueTracs. With the 3.73s you can keep the LSD and as far as I know, the 3.21s do not have the option of the LSD.

Hope this helps more than confuses.

 

[maddog2020]

Thanks all. Helpful stuff.

 

[JPcpa]

Get the 3.73s. Gas is cheap now, will be much better to drive and larger tires if desired will be possible. Much cheaper to pay for on a new one than to regear. And did I mention acceleration will be better?

I just bought my Willys and the 3.73s were the driving factor in this.

 

[cnhmatthews]

Also depends on manual vs automatic. I drive manuals and my first JK had the 3.21 gears. I found the gearing low for starting out in 1st gear and couldn't use 6th gear around town. My current JK is a Willys with 3.73 (manual also) and I find it much better from a stop and I'm also getting better gas mileage out of the 3.73 gears than I did from my last JK on 3.21 gears (both with same tire size and engine). Before I got my current Willys JK I had a JKU Willys with an auto and 3.73. I actually think I would have been better off with a 3.21 for normal city/highway driving with the auto trans. Just my opinion based on my limited experience.

 

[maddog2020]

Summarizing all this it seems that a 3.73 is probably a better choice, in which case I'm a bit surprised that Jeep puts the 3.21 in there as a stock choice.

Benefits of 3.73:

• Better acceleration
• Better low speed control
• Easier pulling away from stationary
• Better (required) for larger tires

Downsides of the 3.73:

• Possibly gas mileage
• I'm guessing that higher revs on the freeway might be noisier

Thanks again for all the input.

 

[JPcpa]

Tow capacity 3500 vs 2000 on JK...that's tells you a lot too.

 

[WNCDave]

As a driver of a JK with 3.21s, I am going to upgrade to 3.73s as soon as the budget allows.

 

[Wild Weasel]

I'm pretty sure there's no good reason whatsoever to get 3.21's except that you might get marginally better gas mileage. Driveability is better with the 3.73's.

I'm sure the only reason the 3.21's exist is so FCA can claim slightly better average fuel economy.

Someone else will have to chime in here to clarify, but I believe the 3.21's also throw in some extra hurdles if you ever want to upgrade in the future. I think it needs a different carrier or some other bits and pieces or something if you want to go bigger.

Given the choice, get 3.73's.

 

[d2mini]

For the average consumer who's just buying the jk for transportation keeping it completely stock, the 3.21 config is fine. Drives fine, pickup is fine, will net the best possible mpg's. But if you are on this forum, you're probably gonna want the 3.73 or more.

 

[aqualungs]

I had 3.21s on a JKU. It's not that bad keeping it stock. Some will say otherwise, but it's subjective. The 3.73 will give you more options like towing and comfortably going to a 33" tire.


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[YoMike67]

A regear will cost about $1400. Mine was $2200 because of the F&R TrueTracs. With the 3.73s you can keep the LSD and as far as I know, the 3.21s do not have the option of the LSD.

Mine ('16 JK Sport 6-speed) came with 3.21 and the TracLoc electronic LSD off the lot.

I am on the OEM 32's, and while its much easier to live with when you row your own gears, I'm still getting some 4.10's at minimum before to long.

 

[aqualungs]

Mine ('16 JK Sport 6-speed) came with 3.21 and the TracLoc electronic LSD off the lot.



I am on the OEM 32's, and while its much easier to live with when you row your own gears, I'm still getting some 4.10's at minimum before to long.

I went with 4.56. I teetered on 4.10, but I decided 4.56 would give the most options. Who knows what I'll want. I have 35s, but could go down to 33s or up to 37s. I'm liking 37s lol


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[Dew]

Alright, two days since OP started this thread. Where is that blue/green/yellow chart?

 

[WillyD]

Alright, two days since OP started this thread. Where is that blue/green/yellow chart?

Here ya go ahaha

 

[WillyD]

Mine ('16 JK Sport 6-speed) came with 3.21 and the TracLoc electronic LSD off the lot.

What I have seen and heard TruLock (locker) is electronic with axle switch and TracLoc is a clutch driven LSD like what came with mine

TracLok skip to 2:55
https://www.youtube.com/watch?v=yxHQeO-Y7GU
TruLok skip to 5:00
https://www.youtube.com/watch?v=K6uAKtb0Q6U

I went with 4.56. I teetered on 4.10, but I decided 4.56 would give the most options. Who knows what I'll want. I have 35s, but could go down to 33s or up to 37s. I'm liking 37s lol

Shhhh on 37s hahaha, If I had the D44 I would have gone 37s. Lessons learned

 

[BeyondYourFrontDoor]

There are many variables, but some folks here don't mention altitude much. My home is above 5000'. Some nearby trails hit 8000' quickly and Jellystone isn't far away with some roads at 11000'. Combining the hills with the altitude and whatever is 'just ok' suddenly becomes a lethargic POS.

I wouldn't buy a 3.21 and upgrade to 3.73... my 75a came with 3.73s and it's still stock tires and it's strictly 'meh' as far as performance at altitude. But... some people love their 35's on 3.21 and I'm sure that config carries a few loaves of bread from the Quicki-mart just fine.

 

[maddog2020]

Here ya go ahaha

This is super helpful stuff, thanks.