Notices
Modified JK Tech Tech related bulletin board forum regarding subjects such as suspension, tires & wheels, steering, bumpers, skid plates, drive train, cages, on-board air and other useful modifications that will help improve the performance and protection of your Jeep JK Wrangler (Rubicon, Sahara, Unlimited and X) on the trail.

PLEASE DO NOT START SHOW & TELL TYPE THREADS IN THIS FORUM
Sponsored by:
Sponsored by:

2008 JKU Regearing help: 5.38v5.86 on 37"s

Thread Tools
 
Old 11-19-2021, 08:07 PM
  #1  
JK Newbie
Thread Starter
 
otigrao13's Avatar
 
Join Date: Nov 2021
Location: Lander, WY
Posts: 8
Received 0 Likes on 0 Posts
Lightbulb 2008 JKU Regearing help: 5.38v5.86 on 37"s

I'm new to owning a Wrangler and know nothing about axles or gearing. I have a 4D Rubicon with auto transmission, stock axles (Dana 44 I believe), and stock 4.10 gearing. I am currently running 37" tires (no plans of ever going larger, but could possibly drop to a 35" in the future). Based on countless searches through the forums it seems I'd benefit from regarding down to either a 5.38 or 5.86.

Can the Dana 44 handle 5.38 or 5.86? Are there benefits or downsides to either of these? Which would you recommend and why? I really appreciate any help the community can offer. I'm hoping your experience can point me in the right direction.



Old 11-20-2021, 03:43 AM
  #2  
Super Moderator

 
Jay2013jk's Avatar
 
Join Date: Jan 2014
Location: SE Pa. W. Chester County
Posts: 1,711
Received 358 Likes on 334 Posts
Default

Welcome to JKF.. Nice Ride.. Curious; what is your intended or planned use for your Rubi? 4.10s w/35s is what I run with a 6spd .. upgraded from 3.73s when went to 35s. 70 mph is at the 2200 rpm level on the highway.. IMHO- Unless you are climbing mountains you won't need the 5's and you will suffer a loss in MPG. If you plan on 40s then 5's would be feasible.
Old 11-20-2021, 06:33 AM
  #3  
JK Jedi
FJOTM Winner
 
TheDirtman's Avatar
 
Join Date: Oct 2010
Location: Southwest Reno, NV
Posts: 6,222
Received 363 Likes on 289 Posts
Default

I have never seen a set of 5.86 gears for a jk dana 44. 5.13 is typically the sweet spot for 37's
The following users liked this post:
otigrao13 (11-20-2021)
Old 11-20-2021, 03:05 PM
  #4  
Super Moderator
 
Sixty4x4's Avatar
 
Join Date: Dec 2018
Location: Calgary, AB, Canada
Posts: 2,559
Received 468 Likes on 420 Posts
Default

Yeah I would go with the 5.13's but you may find them a little slow on the highway if you drop back to 35's. Sweet spot (IMO) for 35's is 4.88's
The following users liked this post:
otigrao13 (11-20-2021)
Old 11-20-2021, 04:40 PM
  #5  
JK Jedi Master
FJOTM Winner
 
nthinuf's Avatar
 
Join Date: Jan 2008
Location: Austin <--> Colorado Springs
Posts: 11,465
Likes: 0
Received 162 Likes on 154 Posts
Default

With my 3.8 Auto, I am running 5.38's and 37's (with a 'measured' height of 36"), which has it just over 2400 rpm's at 70mph. Maybe a bit higher than some other folks would prefer, but works just fine for me.
Old 11-20-2021, 08:20 PM
  #6  
JK Newbie
Thread Starter
 
otigrao13's Avatar
 
Join Date: Nov 2021
Location: Lander, WY
Posts: 8
Received 0 Likes on 0 Posts
Default

Originally Posted by Jay2013jk
Welcome to JKF.. Nice Ride.. Curious; what is your intended or planned use for your Rubi? 4.10s w/35s is what I run with a 6spd .. upgraded from 3.73s when went to 35s. 70 mph is at the 2200 rpm level on the highway.. IMHO- Unless you are climbing mountains you won't need the 5's and you will suffer a loss in MPG. If you plan on 40s then 5's would be feasible.
It is my daily driver, but I also live at the base of the mountains and spend a fair amount of time in the back country, but definitely not rock crawling. I also, spend quite a bit of time on the highway/freeway.
Old 11-20-2021, 08:47 PM
  #7  
JK Newbie
Thread Starter
 
otigrao13's Avatar
 
Join Date: Nov 2021
Location: Lander, WY
Posts: 8
Received 0 Likes on 0 Posts
Default

Originally Posted by nthinuf
With my 3.8 Auto, I am running 5.38's and 37's (with a 'measured' height of 36"), which has it just over 2400 rpm's at 70mph. Maybe a bit higher than some other folks would prefer, but works just fine for me.
When you went to 5.38s did you notice a significant change in the feel? Mine is pretty sluggish currently. Seems quite a few are recommending 5.13's. Is there a reason you went with 5.38's? Based on your response above, I'm leaning towards 5.38. Thanks
Old 11-20-2021, 11:15 PM
  #8  
JK Jedi Master
FJOTM Winner
 
nthinuf's Avatar
 
Join Date: Jan 2008
Location: Austin <--> Colorado Springs
Posts: 11,465
Likes: 0
Received 162 Likes on 154 Posts
Default

Originally Posted by otigrao13
When you went to 5.38s did you notice a significant change in the feel? Mine is pretty sluggish currently. Seems quite a few are recommending 5.13's. Is there a reason you went with 5.38's? Based on your response above, I'm leaning towards 5.38. Thanks
Nope, 5.38's weren't that big a change at all...

I was already running 5.13's and 35's, the bump to 5.38 and 37's came as part of an axle swap. But as far as a 'significant change in feel' goes, I think a lot of it depends on your own personal opinion/perception. Some folks go into a gear change believing it will be instant V-8 power - instead of just bringing the rpm's back up to a more usable level. But just looking at the numbers, there's only like a 110 rpm difference between the two ratios at freeway speeds, you'll be good either way you go.
The following users liked this post:
otigrao13 (11-21-2021)



Quick Reply: 2008 JKU Regearing help: 5.38v5.86 on 37"s



All times are GMT -8. The time now is 04:07 PM.