I drive a 2008 2DR automatic JK with 33'' Duratracs. Last week I had 5.13 Yukon gears put in. The difference is incredible! I can't believe I didn't do this sooner. It feels like my Jeep went from a gutless slug, to a vehicle with a proper engine. Last night I pulled a 350 mile drive in some very hilly terrain, with about half state highways and half interstate. At 70, I'm turning about 2500-2600 RPM's, which is a huge improvement over the 3k RPM's I would turn with OD locked out with my 3.73's. In all the hilly terrain, it didn't downshift once, and I was going up some fairly steep hills at 65-70 MPH!

My MPG so far is about 15 city and 17-18 highway (With a strong 2.5'' lift), which is about +1 MPG over what my old gears got. On the state highways where the limit was 55, my dash gauge was reading 20 MPG, which is usually about 1 MPG higher then real life. My average interstate cruise speed was 72 MPH with a MPG reading of 18.5. Considering they are still breaking in and in woeful need of an oil change now, I'm very pleased.

I'll post more MPG results over the next few days as I refuel. Right now though, I LOVE the 33''/5.13 combo for the Auto JK. It does not feel overgeared as long as I'm not driving over 80, which I never do anyway. Maybe they would be the wrong choice if I lived in Texas, but for the hilly regions I live in they are perfect!

 

If you gonna spend the money to regear, might as well go deep!

 

Yep. I figured that if I REALLY hated it, I could get 35's when my 33's die and just eat the MPG drop until then. Thankfully, my MPG went up, rather then down.

 

your mpg's will actually hover around that area depending on how you drive, I was convinced mine would be near the 12/13 mark but nope keeping it under 70 and not mashing the pedal gets me 16mpg with the 37's. My gears have kept me happy for a long time and were one of the best mods I did.