5.13 gears

[JKChris]

Is there anyone on here that has a 07-11 JK with the 3.8 V6 and a manual transmission that is running 5.13 gears?

I am getting ready to re-gear and was leaning toward 4.88 gears. As I talk to different 4x4 and gear shops around Tucson, many of them are recommending 5.13 gears. I am just wondering if that would be too low? It seems like it would judging by the charts, but I am interested to hear from someone running this set up.[

 

[O_M_Jeep]

also helps to know what tire size you run / plan to run

 

[JKChris]

Sorry! I forgot to mention I am running 35" tires.

 

[Jester32]

With the six speed 5.13 would be fun. The difference in rpm between 4.88 and 5.13 would be about 200-300 rpm. Which is nothin.

 

[Bounty__Hunter]

You want to go slightly lower than the charts recommend, especially with such a gutless motor.

 

[69jeepcj]

I am running a sbc, 4sp trans, 35" tires, 4.88. I dont like them on the highway, but with the v-6 and 6spd they probably would be a good match for your jeep.

 

[Utah_jeepster]

another question is how much city driving to off roading do you really do? Are you playing on hard trails? 4-5 or just doing the easier trail? Is this a Rubicon model? 4:88's and a 4-1 will good enough for lighter wheeling here in AZ but stepping up to the harder trails I would go for the deeper gears.

 

[JKChris]

another question is how much city driving to off roading do you really do? Are you playing on hard trails? 4-5 or just doing the easier trail? Is this a Rubicon model? 4:88's and a 4-1 will good enough for lighter wheeling here in AZ but stepping up to the harder trails I would go for the deeper gears.

Honestly, I am just starting to get into the sport. I definitely haven't done any of the real serious trails yet. I would like to work my way up to that eventually, but for right now my jeep is on the street mostly. It is not a Rubicon, so I don't have the 4:1. Long term, I see myself using it off road only. It really depends on how much I really end up enjoying the sport.

 

[Utah_jeepster]

Honestly, I am just starting to get into the sport. I definitely haven't done any of the real serious trails yet. I would like to work my way up to that eventually, but for right now my jeep is on the street mostly. It is not a Rubicon, so I don't have the 4:1. Long term, I see myself using it off road only. It really depends on how much I really end up enjoying the sport.

There are a lot of arguments about what should come first, second that sort of thing. But if you consider a progression, lift for bigger tires and better clearance on the trails, bigger tires because a lift, jeeps look funny with 31inch tires on a 2.5+ lift, then gears and lockers should be next to fix the diffrence in tires.
This and 4:1 reduction are the two biggest off-road performance add ons for rock crawlers/desert crawlers, and the most expesive, so you shouldnt rush into this.

You need to think this over, since your in Tucson your off roading goes pretty much from easy ((Back way to Mt. Lemmon) to down right extream (Charouleau Gap) that calls for lockers, winch, and rock sliders. Most good trails here in Az require 35+ tires, lockers, TF 4:1, and sliders. The rocks are down right huge and unforgiving.

So once you decide to make this change I would go for the deepest gears and make sure you lock it at the same time since your paying someone to be in there already. No need to cover this road twice.

 

[JKChris]

There are a lot of arguments about what should come first, second that sort of thing. But if you consider a progression, lift for bigger tires and better clearance on the trails, bigger tires because a lift, jeeps look funny with 31inch tires on a 2.5+ lift, then gears and lockers should be next to fix the diffrence in tires.
This and 4:1 reduction are the two biggest off-road performance add ons for rock crawlers/desert crawlers, and the most expesive, so you shouldnt rush into this.

You need to think this over, since your in Tucson your off roading goes pretty much from easy ((Back way to Mt. Lemmon) to down right extream (Charouleau Gap) that calls for lockers, winch, and rock sliders. Most good trails here in Az require 35+ tires, lockers, TF 4:1, and sliders. The rocks are down right huge and unforgiving.

So once you decide to make this change I would go for the deepest gears and make sure you lock it at the same time since your paying someone to be in there already. No need to cover this road twice.

Ok, thanks man. I definitely want to do lockers as well. Do you think I should shoot for the 5.13s then? The 4x4 shops around here definitely think I should if I intend to add bumpers, armor, and such. Others on the forum seem to think that since I have the D30 up front that 5.13s would be a 'weak point' in my set up unless I upgrade my front axle. So, they say stick to the 4.88s unless I intend to get like a PR44 or something. Does this seem reasonable?

 

[Utah_jeepster]

Ok, thanks man. I definitely want to do lockers as well. Do you think I should shoot for the 5.13s then? The 4x4 shops around here definitely think I should if I intend to add bumpers, armor, and such. Others on the forum seem to think that since I have the D30 up front that 5.13s would be a 'weak point' in my set up unless I upgrade my front axle. So, they say stick to the 4.88s unless I intend to get like a PR44 or something. Does this seem reasonable?

That is something to think about, with 5:13's the pinion gear is a weak link, but then again the only real fix is dropping in a Dana 60. A pro-rock 44 would be a wasted step, like I said most dedicated buggies/jeeps in my other group run 60/14 bolt set-ups. Thepeoplee who have this set-up know the risks and take there rigs to the extreme. the question here is are you ready to go that far in one shot?

The problem with 5:13's is the pinion head size compared to the pinion shaft. The larger head puts a lot of radial force against the the shaft, and increase the force by the larger diameter. It is a weak link, one that you wont run into till you start doing the hard obstacles on every trail, but by then you will be trailering your jeep to these trails. But you will have also have broken a stub shaft or two. And at that point you will know that the Dana 30 just wont hold up to extreme wheeling no matter what you throw at it.

If your like me we are going to have to cross this bridge several times I don't just have 5K to drop into axles. I have a dana 30 up front running chromoly shafts and ARB locker. I went with Yukon gears knowing they are the best(going to start an argument with that statement). This set up has been in my jeep for over 5 years and I havn't had any problems. I know that eventually that this axle has to go if I am going to make my jeep into my 'perfect' rock crawler I want.

At this point, go with 5:13's and add a locker to the axle. Like Bounty had said your V-6 isnt a torque monster like a V-8. But it's a strong motor with a verifiable history of longevity. You will be breaking other parts long before you will be shearing pinion gears with 5:13's.

You said you want to start slowly and see if you 'like' wheeling. Out of the box your jeep will take you places you never though possible. Yes youextremeake those extream lines, but with careful wheel placement and practice use of the skinny pedal your jeep can follow the big boys. If you have the extra cash I can send you a whole laundry list of things to change all at once, or go slow and do one thing at a time.

Jeep.
Just Empty Every Pocket.

 

[69jeepcj]

I would listen to the above post. I have alway stuck with the stock dana 30 axle and not had any problem except for replacing the ujoints. I ran pretty tough trail too, but I have a light foot off road most of the time. I guys I went wheeling with had the D60 front and 14bolt rear as well and I followed them where ever they went, except for the most EXTREME. There were even places them or myself couldn't get through, but I went just as far as them. So, as what I think utah jeepster was also saying is you dont need huge axles to do some good wheeling. I agree with him that 5.13 would be a weak link because of the pinion size, the taller(numericly) the gear the smaller the gear head(pinion). I knew a guy that had 4.56 in his yj and sheared the pinion driving down the highway to his wheeling spot for the weekend, I don't know if any other problem contributed to this but thought I'd bring it up.

 

[Bounty__Hunter]

That is something to think about, with 5:13's the pinion gear is a weak link

Not as much of a weak link as it's predecessor axles, the JK has added a lot of beef to the pinions over previous years.

Go 5.13, I don't think you'll regret it. The charts compensate for the increase in tire height, but not the huge increase in mass you have to get moving, so best to go a bit deeper than recommended.

I rock 5.38 in my YJ and it loves it on road and off, cruises 70mph with no problem on 35" tires.

 

[JKChris]

Thanks guys. I really appreciate the input. As it stands now, my biggest problem is getting any of the local shops to even call me back. Doesn't seem like they want my business at all. I have been over thinking the hell out of this stuff... Haha

Thanks again