I've read various opinions on going to 5:13 vs 4:88's but does anyone have an opinion or "hands on experience" on whether to go 5:13 or 5:38 on a '07 Rubicon 2 Dr. w/AutoTrans. on 35" KM-2's? To say this is gutless with the stock 4.10's is a gross understatement. I'm hoping to score a SuperChip Programmer at the time of gear change.

 

I am happy with my 5.13s and 35s. BUT if I could snap my fingers and have 5.38s I would in a heartbeat. I love the lower ratios.

 

Thanks! I was kind of thinking that also. I've been reading various threads on what brand to buy. Is Dana the only US made gears?

 

5.38 pinion gears are pushing the limits on durability. There's been little written about 5.13 failing, but I'm not sure a whole lot of off-roaders are running 5:38's yet.

I vote you put in 5:38 gears and run them for a year. If you don't have any issues, then great!

I'm just saying it's pushing the limits.....

 

I think that is what we are all about...pushing the limits.

 

I have 5:38's with 37's. My speedo is exact but no power in the mountains for some reason. Would not climb high elevation mountains in New Mexico and Arizona. Live in Virginia. Could that be a reason maybe flip a switch????????

 

I just ordered 5.13s but have been debating returning them to get 5.38s to squeeze out a little more power. It seems most everyone uses 5.13s for 37s due to those being the lowest ratio available for along time. As far as the 5.38s durability, I guess we'll have to wait to see, but it seems its not much more than the 5.13s.

 

Do you think that was do to the gearing being too low? (or numerically high)

 

I believe there were some threads here on this. From what I understand the 5.38 have much fewer teeth and they are smaller/thinner and therefore more prone to break, and when they do there aren't many left to compensate. The weak spot moves from the drive shafts, where broken things are easier to access, to within the axle. A local shop that works only on Jeeps doesn't recommend it.

I am curious myself between 5.13 and 5.38, as eventually I may re-gear.

 

So are you running 5:13's now? How many miles on them?