Im looking to get a 2015 JKU, then add a 2.5 lift and 35's. Most seem to come with 3:21 gears, not a preferred 3.73. This used to be an issue with the old engine, how is it with the new engine. Should I definitely hold out and find one with 3:73 or would a jku with 3:21 be ok. No rock crawling, but will be on trails, etc...I don't care ab out gas mileage... Anyone with 3:21 think their jeep feels underpowered?

 

I've got a 2012 with 3.21 gears running 35" trail grapplers and a 3.5" lift. It's not going to outrun anyone, but I do just fine in the trails/rocks/highways.

 

Agreed...

 

Mild trail running is probably not a problem but if you get into any rocks, it will be. While the 3.6 is light years better than the 3.8, it still has next to zero bottom end torque. I have a 12 with the 4.10's and the rock trac and, IMO, that still leaves something to be desired in rocks even with 33's.

 

I have 3.73s with 35s and can barely stand it on flat roads. Hills, forget about it. My plan is to go 4.56s. Oh yeah, and it's an auto.

 

Just switched to 35s a week ago running 3.21 auto. Got my regear to 4.56 booked for next week. Its not the worst thing possible but it's pretty annoying, gas mileage sucks, and mostly I know there's a lot of unused oomph that I'm missing out on.

On the flip side, if you go straight to 35s you might not know what you're missing though?

 

Running this setup, gas mileage does suck 14.5 why, 12-13 in town, but I'm running the 93 octane superchips so it's not unbearable to me, but the. Again, I've never been in one with any other gear combo, so I might be blind.

 

Thanks everyone. looks like i will look for a jku with 3:73's, or will just go for a rubi with 4:10. I currently have a 2007 jk auto with 4:10 ( saharas had them stock back then) on 35's and have no issues with the 3.8. I would like to try to keep it as similar a setup. Also I will run km2's that run small...

 

have a 2014 JKU which had 3.21's and 35's got great gas mileage but had no balls. have a 6 speed manual changed the gears to 4.56 now I can use 6th gear and have plenty of power but went from 18mpg to 14mpg but I didn't buy the jeep for mileage. just saying

 

I have 3.73's, a 6-speed manual, and 33's.

It's not enough. Not for highways, not for crawling, none of it. I can't imagine running even bigger tires on a heavier rig with higher gearing.

I'd get the Jeep with 3.21's, skip the cost of 3.73's and immediately regear to 4.56 or 4.88++ depending on the application.