I have a 2011 JK Automatic with the 3.8l . I have 5.13 gears adj. Front and rear track bar. Adjustable front lower control arms. A new upgraded front drive shaft. And grease able ujoints in the front.....
So the question is what else do I need?

 

I'm sure others who have this set up will chime in, I dont, but from what I understand.....

Sounds like you have gearing taken care of. Would assume you have a programmer already to adjust for the gears, you will need it for new tires size too.

With 37s I would think bare minimum on the front stock D30 or 44 C gussets ....and axle sleeves

Assume you have a tall enough lift, fender flares ect you allow full wheel stuff

Good luck with the buikd! I myself have a 3.8l and auto....33s and stock 3:73s.....for now

 

The 3.8 is underpowered, you will wish that you had 5.38's. And a supercharger. And a v-8. (it's not as bad as all that, but I do wish I had more power...)

Start looking for threads talking about strengthening the front housing (gussets, sleeves, truss, etc) to see what fits your budget and needs. There are a bunch of different opinions on it, so read as much as you can. For any other components, like shafts and hubs and whatever, leave it alone until there is a reason to replace. (my opinion, anyway)

Other than that, 37's are just about clearance. You want more backspace to move the tires out and enough trimming and/or lift to keep them off the body. Hard to say what you will want/need to do, since all builds can be different.

 

This is my jk. I had to replace the front drive shaft because stock sucked and that boot ripped off and the shaft seized . So I upgraded. Also I don't do highway driving really. Maybe 60 mile drive to my parents and trails. I have a charger hemi for daily. Also my front is a d30. Which I'm looking for a d44 from a junk yard

Is there upgraded steering? Like pump? Or pitman arm?

 

I have a programmer from superchips.

 

It's bearable if you live where it's flat.
My 07 auto with 5:38s and 37s was terrible out here in the mtns.
Even with a extra tranny cooler with a fan on it I was on the verge of overheating it on long grades.
Add a additional tranny cooler if you haven't already.

 

im on an auto 3.8l with 41.5 and cant complain.. in hilly areas it would struggle and i may hate it a tad but as long as your not towing im not concerned. Has plenty of power for me especially in this flat area im in now. i dont even have an extra tranny cooler... I personally wouldn't get a turbo, id just do a motor swap myself, but not many will do that. id say power steering cooler also as even with hydro my box got very got...

 

I've run 37s for the last six years on my '09 JKUR with the setup in my profile, no issues whatsoever that would lead me to not recommend them. At the risk of stating the obvious, you need enough lift, bump stop, wheel well clearance and wheel offset to prevent rubbing, and deep enough gears to permit the engine to run in its power band. You can pull it off with around 3" lift, flat flares like MCEs, Bushwackers, etc., and at least 4.5" of wheel offset via wheels themselves or spacers. With 5.13s you should be ok, but you'd be better off with 5.38s. The 3.8L is a notorious dog, but mine has cheerfully taken me on long journeys, conqueed tough trails and returned me home. The only problem being a cracked exhaust manifold.

 

I had 35s before the 37s. Had rubbing in the rear as you can see from the picture. But cut that area and seems fine. But rubs in the front on hard turns. Have 1.5in wheel spacers.

 

Question then for you....steering issuses?