ry2dsrt

My JK is my daily commuter (80%) and weekend warrior off-road vehicle. After a upgrade to 4" lift and 35" tires, I am considering either a 4.88 or 5.13 Sierra gearing change to the Dana 44s. I don't think I will ever go to larger diameter tires.

What has been your experience with these gearing changes?

My goal is improved throttle response and acceleration around town, highway, and climbing mountains on the highway.

Second goal is improved off-road performance without too much concession to on-road performance.

Thanks

nthinuf

You have an Auto Rubicon

5.38's ...

Millerman999

AUTO... I'm runnin 40's 5.38's man all the way.

mjm

If you have an Auto Trans I would look into 5.13 or 5.38.

This thread that I started might help: https://www.jk-forum.com/forums/show...(High-Altitude)

jessmcquaid

I have an auto with 35"s and went with 5.13's. It feels stock again to me. All the local shops talked me out of 5.38's but I kind of wish I had anyway. If you don't mind the stock drive with the smaller tires you will be happy with 5.13's. I was hoping it would have been more peppy gearing wise.

nthinuf

I know what you mean. Unfortunately, gears can't overcome a weak engine/transmission combination. They just bring you back to a stock or slightly better than stock ratio. In the case of auto JK's, gearing for 'better than stock' is definitely the way to go...

mjm

Why is this?? I have run into the same thing when calling around, most shops advise to go with 5.13's and not 5.38's. The shops I'm calling are very reputable and deal with JK's all the time.

Millerman999

5.38's are at super high RPMs when you start runnin bigger and bigger tires. I run 3000 RPMs goin' 70 in 3rd gear.

Tuto

5.38 w/ Auto transmission at 70 MPH what are the rpm

Maybe that is way shops recomend the 5.13 -

mjm

According to the chart on FAQ 2495 rpm at 70 MPH running 35inch tires, Auto Trans. 2380 if running 5.13 with same setup. Not too much of a difference. Maybe the shops use a different chart.