I am going to be putting 35's on my JKU w/auto trans and am going to regear at that time. Are there any downsides to running 5.38's vs 5.13's ? It is primarily a DD.

 

You are probably going to hear a lot of the oppisite, but I have 37's that measure 35.5 and an auto with 5.38s. I wish I could go lower, even cruzing on the freeway.

 

you cant do 538s with a dana 30 in the front

 

Most people with Auto's are running the 5.38's. Thats what I'll be going with when I have the change to drop.

 

negative.

 

With a Sahara, you're limited to 5:13's


I have KM2 35's, I just got 5:38's last week.

With less than 150 miles on 5:38's, I already feel like I could use lower gearing just driving down the interstate (freeway) @ 65-75mph

I am flashed with 87 \ tow tune and I have CAI.

Maybe I need an S\C or hemi swap?

 

I run 5.38s and love them. Wish I could go lower even.

Flash

 

Pluke the 2 are more people with autos running the 5.13's? I thought 5.38's were more the norm? If thats the case I need to rethink my current strategy haha.

 

Majority of autos are gonna be at 5.13. Unless its a rubi, which will more than likely have 5.38 depending on tires

 

As noted above, you can't run 5.38's in that front d30. You are stuck with 5.13's unless you choose to swap in a front d44. Open the drivetrain faqs and plug some numbers into the chart to see what rpm's to expect. ( divide by .69 if you want to see your OD Off rpms)

The downside to lower gearing (higher numerically), is that the pinion gets progressively smaller and weaker. If you have a heavy foot or like to bounce through the rocks, you may be better off choosing the next higher ratio (lower numerically). On the plus side, auto's are a lot more forgiving than manuals with the shock to the gears/drivetrain.



For my onroad/offroad needs, it's 5.38's all the way. (or 5.13's if you have a front 30)