rays0852

4.10s are the appropriate gear for a 2012+ JKU auto running 35s?

I bought a Sahara and now I am finding out that 4.10s as an aftermarket R&P are hard to find for a D30.

I really don't want to go 4.56s because I feel 2700-2800 RPMs is too much to turn at 70mph. Plus it almost assures I can never do 80 if I need to without winding my motor out.

I really am an idiot for not buying a Rubicon. 1st Jeep mistake.

mattgt5

I actually like 3.73 with 35"s and 4.10 with 37"s on the new engine w/ auto. I have run various configurations on the new engine and feel the best compromise for mpg and power is what I listed above. Just my opinion from experience with my 3 different 3.6l wranglers.

rays0852

So I have 3.21s now.

Do you really think that I should spend the money to re gear to just 3.73s?

Seems like a lot of money to spend for such a small difference. I would be throwing in a locker or LSDs while I'm at it.

I am planning on towing a small to medium sized pop up in Florida. Something like 1500 to 2000lbs.

wranglerboy

I am living with the same regret. I bought a sahara and now want 35's and also think 4.56 is just too much. Finding 4.10 gears is not as easy as 4.56 but they are out there. Now my problem is I was quoted $3950 for a regear! Should have got a rubicon!

suicideking

That's WAY overpriced! My local shop does regears for $1400 installed, there's another shop about an hour away that does them for $1000.

I have 3.73 and 35's. I find it livable after using an AEV Procal. I noticed a HUGE difference when I used the Procal. If a shop had charged me $1000 and told me it was re-geared, I'd believe them.

3.21 would not be livable, I'd want a re-gear. With the 3.73, I find it a little weak at times. If I was going to re-gear, I would skip the 4.56 and do 4.88.

Also wish I had bought a Rubi. Instead, I did a front axle swap and put in a Front Rubi D44. I also put an ARB in the rear. Definitely would have been much less to just start with the Rubi.

hypeiv

I think pentastar + auto + 4.10 is perfect for 35's...

but that doesn't really help you. If I were you (35's pentastar w/ 3.21s) I would find a shop that can regear you for $1400-$1500... (maybe throw another grand at it and get an air locker installed)

Just get 4.56's, Its unlikely they will really be that aggresive... no more aggressive than a stock rubi running 32's. And they will be great offroad.

I have 3.73's and don't feel any need to upgrade but if I did I would likely go to 4.56's, but I wouldn't recommend upgrading to 3.73's from 3.21 (its too small of a jump for too much of an install cost). I plan to stay at 3.73 untill my LSD craps out on me then upgrade to a rear locker and 4.56's

rays0852

That's my other problem. Cost.


4.10 gears with master kits are over $1000 just in parts. Add in labor and a selectable rear locker and it just gets silly.

I was quoted $2425 yesterday by 4 wheel parts for just a regear....no locker or LSD.

I should have bought a TJ I swear.

hypeiv

How much are 4.56 kits?

Its unlikely your highway mileage will change much between 4.1 - 4.56... I was under the impression regear kits for front and rear would run about $500-600 and install is $700-1200.

While they are tearing in the axles you might want to look at getting a detroit truetrac lsd if locker isn't in the budget.

hypeiv

Lol I hear that... while the JK is much cheaper than my last toy, I sometimes wish I had something not so expensive to throw around off road than my daily driver.

rays0852

Gas mileage is not really my concern. It's 2800 RPMs at 70 that concerns me with 4.56s.

Personally I think that's a recipe for a shorter engine life. I travel with my Jeep club almost every weekend. All rides in FL are about 2hrs away on interstates. Plus my occasional family trip to the NC mountains to see my parents has me wanting to pull 75-80 sometimes. So then Im running almost or at 3k.

So you see my dilemma.

4.56 kits are about 300-400 cheaper depending on brand which pays for half a locker. 2012 has been out for over a year and a half. You think the aftermarket would have adjusted their production of parts to meet the needs of the new drive train.

My buddy has a 2012 6 speed with 4.88s. It's a joke.

We were in 4 wheel low on a trail and he was doing 15 mph in 4th gear at 3700 RPMs. Throw those stupid gear charts out the window. They are wrong.