I have an 07 jku 35's, 6spd and 3.21's here in the altitude of Colorado around town isnt bad going up to the mountains kinda sucks but it gets there once in the hills I use 4lo . I am runnin a cat back exhaust,cold air intake,throttle body spacer and a sc flashpaq in tow mode with the speedo corrected. I was only getting bout 12.5 mpg now wit the sc Im getting around 14+ mpg around town. I will be gearing as soon as possible.

 

I ran that way for two years w/ a 6 speed, had no issues with it. Just put in 5.13's and 37's, and still getting used to how fast I need to shift it. The 3.21's would have screemed with my current setup I'd think..

 

Your rig looks sweet!

 

Thanks!! Been working on it for 3 months EVERY Saturday, drove it for the first time last weekend finally.

 

Only choice will be a procal. No tuners available yet for the 11's and 12's

 

I've got a 2011 6 speed 2 door on 3.21s motivated by the 3.8L. I'm planning on running 35's as soon as I can and when I regear, I'm going 4:10, not 4.56. I like my current tires and 3.21 gears, and going to 4.10's with 35's which is a (unnoticeable) 4% increase. No need for 4.56. It will also be safer on the ring and pinion to have a little more room in the smaller D30.

 

I run a 2012 with 3.73's and 35's. 5 spd auto. drives good but wont tow anything! So 3.21's will be running at lower rpm's robbing some torque. look at the rpm chart in the "questions every newbie have" thread and look at the chart for speed and gear ratios and tire sizes. that chart is based on 70mph . I did a real time comparison with my jeep using 30", 32" and 35" tires (measured true size) and found the chart to be accuratte. I also learned that the rpm drop from 70mph is about 200 rpms per 5 mph you slow down on all 3 tire sizes. I find that running about 2500 to 2900 rpm in 5th is a good cruising rpm for me at 60 to 65mph. So when you decide to regear check that chart and consider your use on road/off road.

I am going to 4.88's for my 35"s next week as my 3.73's just dont give me enough power to the road to tow my trailer and wont give me good torque to wheel in 4 hi.

Good luck

 

Have you tried down shifting?

 

... With 285 HP you will be FINE.

 

My 2012 auto has 35" MTR on 3.5" of lift and 3.21 gears with a ProCal...it runs amazing!
After using the ProCal, it feels just like my Jeep when it was stock. I'm still fast off the line and I haul ass. I have had no trouble rock crawling either. I originally planned to regear but I see no need at this point, I'll just wait till I can afford new axles.
A lot of people who haven't driven or been in a lifted 2012 go on with horror stories about how sluggish you will be and how terrible it is...I'll burn all of them!!
Also I average 14.2mpg with 90% city and me driving like an asshole