I've got some good advice so far; however, I am still not sure how much lift I need for 37" tires. Some say 2.5" works, others say 4", and I just read that I might need 8".
Does anyone know how much lift I need for 37" tires?
I am running 37's with Rock Krawler 2.5" Max Travel lift and flat fenders. BUT
, RK gives more lift than advertised. I gained 2.5" in the rear, and 4.25" in the front. I run 3" bumpstops in the rear, and 2" in the front. I kept my lift low to keep the center of gravity low. Lots of off-camber / hilly trails where I live.
The front axle is sleeved and has C-gussets. Poly Performance ball joints. Factory lockers front and rear (Rubicon). No need for a Dana 60, unless you really intend to pound hard on your Jeep. Upgraded axle shafts (i.e. chromoly or RCV) will only make your ring & pinion the weak point if something breaks. An axle shaft is a lot easier to replace on the trail than a R&P. So, I'd stick with a stock shaft, or chromoly at the most. And you will likely need new gears to handle the taller tires, even with the 3.6L. You will need to trim the rear end of the rock rails about 2-3", and the pinch seam in front of the rear tires about 2-3" (use a Sawz-All). Stubby front bumper will give more clearance for the front tires. And wheels that have about 3.5" or less backspacing to prevent the tires from rubbing the lower control arms.
Follow PlanMan's thread on how to run 37's here: https://www.jkowners.com/forum/showthread.php?t=31183
I'd recommend that you drive your Jeep off-road in stock form with a local Jeep club for a few trails. Then upgrade it to fit how you need it to accomplish the type of trails you intend to run. A stock Jeep is pretty amazing in capability.
BTW, that chart above is for the 3.8L engine. You have the 3.6L engine. Let me try to find the correct gear chart for you.
EDIT: Here you go. Looks like for the 3.6L you would need 4.56 or 4.88 gears for 37's.