Just curious bc i havent found anyone with this set up......with a 3.8 Automatic. I have a 2011 jku rubi auto with a 4.5 lift and 37 km2s(35.75)actual and 70lbs each. Im a dd will occasionally ride these muddy farm roads, no rocks here. the 410s are alright but if you get on the highway it searches alot and efficiency goes down..but to me..it seems like i dont need much lower to be close to stock again..yes ive read hundreds of threads and its always 5.38s or 5.13s..I have a set of Yukon 5.38s unopened in my garage bc i was 'talked into' buying them, they are probly going back to northridge today in exchange for 5.13s, but i wanted to see if anyone ever ran 4.88s with this set up. im more interested in gas mileage and less gear shearching at higher speeds, the 410s seem fine around town but get above 45/50 and its fickle about which gear it wants. set the cruise at 65mph and you look down and youre in the 2300 rpm range and look back down a minute later its in the 3000rmp range bc it kicks outa od.I know this is old hat knowledge but maybe someone else is less privy to it or is about to make some mods and will end up in this boat. Should i even consider 4.88s? or is 5.13s IDEAL for how i just describe my driving intentions bc everyone asks or says..it depends on how ur gonna drive it. thanks for some input.

 

Sure, it's doable... I'm running same tires with 5:13's and a 6 speed and rpm's still run a little high for my taste.

 

I am running the 5.38s and my RPM isn't bad at all. I would say run the ones you have. At about 70, I am running around 2700 rpms or so. Good luck with your decision!!!

 

Depending on the roads I am on, I will usually just turn the overdrive off. This keeps the tranny from searching as much, I actually get better mpg's on hilly roads and my tranny temps stay cooler.

 

With a Manual trans the 4.88 would be totally livable. But with an Auto Rubi, I would go with the 5.38. The Automatic just robs so much power away you will want the extra. And the difference in RPM from 4.88 to 5.38 is only like 300 rpm difference at highway speeds.

 

..is there anyone on this forum who runs 37s with 4.88s and an AUTO on a 2007-2011

 

No... Everyone runs 5.13s or lower and then complains about broken gears. I like you question as I have the same plans to go to 4.88s but have not found any feedback on this setup.

 

I'm running 5.13's with 37's and an automatic transmission. It doesn't actually feel that bad under normal usage except when I'm trying to maintain speed up some of the 75MPH highway climbs in Colorado. I'll be honest, I can't help but wish I had gone with the 5.38's from time to time. If I were to do it again with a similar setup, I wouldn't consider 4.88's at all. I'd run 35's on 5.13's and 37's on 5.38's if I were to build another rig right now.

 

i live in the delta flat lands and i dont mind doing the 5.13s its just that the 410s arent horrible until around 55mph, i run with the od off and in 2nd gear around town up til 2800rpm. the reason im curious bout the 4.88s is that its lower than 4.10s and i dont need much lower (i dont think), no elevation and no hard wheeling, just want to battle and win a headwind at 55mph, dont tow anything, its gonna cost me the same regarless i just want the right set up and was hoping there was at least one person on here running 37s and 4.88s and auto, if i go with it ill definitely give some feedback and it could very well be DONT DO THIS SETUP. either way its tempting to just keep these yukon 5.38s i have boxed up to go back to northridge. just dont want a ton of rmps going 70 and 70 is plenty fast for me 72 tops. thanks