4.56 or 4.88s?

[ngirondo]

Hey guys I’m at a point where I need to upgrade gears in my 2017 Willy’s JKU. I currently have 3.73s and 35s. The addition of a overland trailer I just built is what’s pushing the gears but my question is do I go with 4.56 or 4.88s I’m leaning towards the 4.88 since we tow the trailer all over the place. Any inputs would be great thanks!

 

[MuckSavage]

I'm going with 4.88.

 

[hemi_meat]

How much of a MPG loss is 4.88 vs 4.56 on the highway? Would 1-2 MPG @ 60 MPH be accurate?

Sent from my SM-N910V using Tapatalk

 

[Hristo34]

4.56 for manual, 4.88 for auto, with 35s. That's the rule of thumb for the TJ and I believe they share the same 6 speed.

 

[Buliwyf]

4.88
Don't fear the gear.

 

[GB_Willys_2014]

I have read on a number of occasion that the D30 is not compatible with gears larger than 4.56 due to pinion size.

But, I have no direct experience with this.

Anyhow, I really like my 4.56 gears. I have a manual transmission.

 

[PhulesAU]

D30 it TJs have NO problem with 4.88 gear sets. If there's a lot of hwy travel I'd be happy with 4.88

 

[ngirondo]

4.88 it is thanks guys

 

[SoDakSooner]

4.88's are ok in the D30 fit wise. I have 4.56's and wish I had gone to 4.88's in retrospect. No issues with the 4.56's but would like a bit more low end. I typically don't drive much over 65 anyway.

 

[CaptainChaos]

I just put 4.88s in a few weeks ago. I had 4.10s and and they did alright, but 4.88 works so much better. I have an auto and 35s. I mostly regeared to pull the trailer better.

 

[Jwood]

I put 4.56 in my JK, 35’s, 6spd. I started to go 4.88 but was talked out of it by my tech and have no complaints. 4.56 provide great power and I’m still able to cruise down the highway comfortably.

 

[WU7X]

I have 4.56 in my 5th gen 4Runner. Used to also run 33" Coopers. Now running 32" BFJ TAKO2's and still like my gearing. BUT, if I was going to run anything bigger like 35s, I would seriously look at the 4.88 gears.

 

[john02tj]

I have 4.88s in my 2015 JKUR, When I Had 35s The RPMs on the highway were up there but I always planned on moving to 37s and now its a great match. I pulled my 2017 Triumph explorer XCA (650lbs) bike from Tucson to Ogden Utah with no issues even having the Jeep loaded head to toe with my crap. If you go to 37s look into a big break kit. I have the power stop and I love the upgrade.

 

[FordGuy1]

I think you are always better off with a little to much gear than not enough. The only negative is that you really start to loose pinion strength, especially above a 4.56. 4.88 dana 30 has a pretty small pinion.

 

[Justincredible]

Up until towing the trailer you were happy with 3.73, so the 4.56 should make a big difference and be a bit stronger than 4.88 in the D30 front.