37s and Gears

B

BobbyJits

New member
Hi First Post here - I have a 2009 4 door automatic JK - I am getting 37s next week (currently have 35s that were temporary)….I am re gearing and would love to hear peoples thoughts on 4.88s or 5.13s….the shop is recommending 5.13s….and I know a lot of people have those gears and are happy….i have read other people's comments who say that its rough on the highway with the RPMs that high….Anybody ever get 4.88s and wish they got 5.13s or vice versa.

As far as jeep use - its mainly an around town driver (I work from my home office and don't have a commute to work everyday)…..I do light off roading but look to do more in the future (if time permits - have a newborn on my hands now)

Thanks!

Bobby
 
1BAMFR

1BAMFR

New member
I run 4.88s with 37s.

Mine is a 6spd. Though

You might be better with 5.13s with your automatic
 
JKFlyer

JKFlyer

New member
5.13 with auto 3.8. Look at sticky threads. Eddie posted a chart

Sent from my DROID RAZR HD using WAYALIFE mobile app
 
Atch

Atch

New member
I have 3.8 auto 37's with 5.13's. I'd recommend 5.13's but be easy on the skinny pedal when wheeling since you have a D30.
 
jeeeep

jeeeep

Hooked
I have a 2010, 4.88's and currently 35's. I chose 4.88's because my future plans beside the 37's is a v-8 swap and 4.88 are better suited with a v-8 versus 5.13
After doing the math, 4.88's and 37's are closer to stock on the 2010 auto. If you have a D30 and want more of a DD, I'd chose 4.88's - you'll notice the difference, your mileage won't take too big a hit and when wheeling you lower the risk of breakage versus the smaller pinion of the 5.13's
 
wayoflife

wayoflife

Administrator
Staff member
BobbyJits said:
Hi First Post here - I have a 2009 4 door automatic JK - I am getting 37s next week (currently have 35s that were temporary)….I am re gearing and would love to hear peoples thoughts on 4.88s or 5.13s….the shop is recommending 5.13s….and I know a lot of people have those gears and are happy….i have read other people's comments who say that its rough on the highway with the RPMs that high….Anybody ever get 4.88s and wish they got 5.13s or vice versa.

As far as jeep use - its mainly an around town driver (I work from my home office and don't have a commute to work everyday)…..I do light off roading but look to do more in the future (if time permits - have a newborn on my hands now)

Thanks!

Bobby
Click to expand...

Honestly, if you're going to run 37's, 5.13 would be the exact ratio you would want to be running. If anything, 5.38's would give you a bit more power but, I don't typically recommend that ratio in a Dana 44 as it will leave you with a pinion that is very small. 4.88's will still feel sluggish. You just need to make sure to get a Superchips Flashcal or AEV ProCal to properly calibrate your speedo afterwards or else your shift points will be off.
 
B

BobbyJits

New member
wayoflife said:
Honestly, if you're going to run 37's, 5.13 would be the exact ratio you would want to be running. If anything, 5.38's would give you a bit more power but, I don't typically recommend that ratio in a Dana 44 as it will leave you with a pinion that is very small. 4.88's will still feel sluggish. You just need to make sure to get a Superchips Flashcal or AEV ProCal to properly calibrate your speedo afterwards or else your shift points will be off.
Click to expand...

Thanks - I should of mentioned that the pro cal is also going in next week with the regear.
 
You must log in or register to reply here.
Top Bottom