Jeep Wrangler Forum banner
  • Hey everyone! Enter your ride HERE to be a part of JUNE's Ride of the Month Challenge!

1 - 15 of 15 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
Hey guys...

Sorry if this has been beaten to death but i have a 2011 JKU Sport and I am running 35s on stock axles. I want to go bigger and go to 37s and add in lockers. Been looking for Rubicon axles and will re-gear but my question is... Will the 3.8 perform well enough to do it? I've been told i should start over and just find a Rubicon but i got to be honest i friggin love my Jeep and would rather not go that way.

Also if i get new axles and re-gear what else would i need to do? I got a new stabilizer bar and a track bar already when we did my lift.

4508607
 

·
Registered
Joined
·
1,902 Posts
1) Axles ( not just stock Rubi take-offs)
2) Gearing
3) Brakes
3) Steering

Everything else I wouldn’t have a problem replacing as I broke them, but those are the 4 things I’d do before going to 37’s

Previous Owner ran 37’s on my jeep, and I just will not do it. My axles have new inners, gusset/trussed, and I have 5.13 gears with a 3.6L manual
 

·
Registered
Joined
·
1,713 Posts
Do a search, the topic is beat to death. The list gets long if you off-road hard.

In addition to what's listed:
hydraulic ram steering, couldn't turn the wheels in the rocks
Forged rear axle shafts after the stock flanges bent
Big brake kit so I could stop again
Cut some of the body away in the rear fender area
4.88 gears (go 5.13)

I ran 37's for 3 years and 30k miles. Moved to Europe so went back down to 35's. Much improved ride on the road, quieter, faster, better mpg. I'll only go back to 37's when I get back to the US, get a different daily driver, and then I can play in the rocks again.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #4 ·
Do a search, the topic is beat to death. The list gets long if you off-road hard.

In addition to what's listed:
hydraulic ram steering, couldn't turn the wheels in the rocks
Forged rear axle shafts after the stock flanges bent
Big brake kit so I could stop again
Cut some of the body away in the rear fender area
4.88 gears (go 5.13)

I ran 37's for 3 years and 30k miles. Moved to Europe so went back down to 35's. Much improved ride on the road, quieter, faster, better mpg. I'll only go back to 37's when I get back to the US, get a different daily driver, and then I can play in the rocks again.
haha yea you are not kidding... Thanks just did a search and will take a look...
 

·
Registered
Joined
·
754 Posts
Reinforce the "C's", new heavy duty ball joints(I went with Rare Parts), big brake kit, flat fenders, new1350 driveshafts, heavy duty axle shafts front and rear, I will be going to 5.13 gears from 3.73, a deeper wallet with arms long enough to reach all the way to the bottom, you'll need the money........
 
  • Like
Reactions: SirCraig

·
Registered
Joined
·
1,902 Posts
Reinforce the "C's", new heavy duty ball joints(I went with Rare Parts), big brake kit, flat fenders, new1350 driveshafts, heavy duty axle shafts front and rear, I will be going to 5.13 gears from 3.73, a deeper wallet with arms long enough to reach all the way to the bottom, you'll need the money........
I also went with adams front and rear shafts..... but forgot about that already, because it was “cheap and easy” compared to the rest!
 

·
Premium Member
Joined
·
9,626 Posts
Manual or an auto? Is this a toy or a driver? With the 3.8 you have an issue, not enough power. If you have an auto and it is a driver you are looking at 5.38 gears minimum in my book. That means upgrading to D60 axles so you have $20K invested right off the bat but it will come with brakes and you can get the axles in the proper width so you have a decent scrub radius. Of course it will require new wheels.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #8 ·
Manual or an auto? Is this a toy or a driver? With the 3.8 you have an issue, not enough power. If you have an auto and it is a driver you are looking at 5.38 gears minimum in my book. That means upgrading to D60 axles so you have $20K invested right off the bat but it will come with brakes and you can get the axles in the proper width so you have a decent scrub radius. Of course it will require new wheels.
it's a manual... It's a driver but I work remote so i don't really put a ton of miles on it. That was really my main question if the 3.8 could even handle 37s.
 

·
Premium Member
Joined
·
9,626 Posts
it's a manual... It's a driver but I work remote so i don't really put a ton of miles on it. That was really my main question if the 3.8 could even handle 37s.
I would still go d60 and 5.38's. I know it is a lot of money but getting the axles the correct width means a better scrub radius. I have a manual with the 3.6 running 4.88's but really wish I was on 5.13's. Running 37's you really want at least 3.5 inches of backspacing, 3 inches even better. But when you go with that much backspacing it really makes the scrub radius bad. I can feel the tires flexing even driving in a straight line. Liveable but I will be glad to upgrade.
 
  • Like
Reactions: SirCraig

·
Registered
Joined
·
1,074 Posts
Yes the 3.8 can turn 37s. I’ve been doing it for 7-8 years. You need at least 5.13s. Some people run 5.38s but I personally would recommend against that. If you want to wheel your Jeep off road and still have it be reliable, you’re looking at around $15k in upgrades. If you’ve done the research you know that already. I did the upgrades piecemeal over time and did all the labor myself, including the regear. It was fun to have the projects and my Jeep is now very capable. That said, even with upgrades, 37s on 44s are still marginal. If you can get over the lump expense, I would just go straight to 60s from the get go. For example, a set of Dana UD60s. That will take care of a number of expensive things you’d otherwise have to upgrade or address, such as gearing, lockers, chromoly axle shafts, upsized brakes, aftermarket or reinforced axle housing, eliminating unit bearings, etc.
 

·
Registered
Joined
·
6,774 Posts
I ran 5.38 Yukon’s with an OX locker and RCV axles on 37” Pitbulls. It was a great combo, around 2100rpm at 60mph on the highway. 5.13 wasn’t quite enough gear for the 3.8 auto and heavy 37s. 5.13 is a great choice 35s.

5.38 gears with the 3.8 auto is about the equivalent of 4.56 gears with the 3.6 auto.


Sent from my iPhone using Tapatalk
 

·
Registered
2017 JKR...
Joined
·
1,902 Posts
You don't need 60's for 37's...replace that 30 with a pr44 or equivalent and put chromoly shafts in the rear axle and you'll be fine...
 
  • Like
Reactions: SirCraig

·
Registered
Joined
·
754 Posts
Oh, and when you go to do your axle upgrades, do the welding and reinforcing of the "C's" first before you do your ball joints. You'll save yourself the headache of having to pull them so you don't melt them when you weld.
 
1 - 15 of 15 Posts
Top