Jeep JK Unlimited vs TJ Unlimited

[TRD270]

With the 4runner possibly being sold it’s time to start figuring out which Jeep to buy. I was pretty dead set on a JK Unlimited, but then I started thinking about the small run of TJ unlimiteds.

What are the pros and cons of both.

Two door vs 4 door
Cargo capacity
Wheel base pros and cons to each
Suspension differences
Drivetrain differences
4.0 vs 3.8 since I can’t afford a 3.6 year
Axle differences
Parts available

So I can’t afford a Rubicon JK, but I have found a few Rubicon TJ Unlimited that are in my price range.

On a TJ I feel the Rubicon is worth it, they are getting “older” and the prices are getting closer to their non Rubicon counter parts. Non rubicon TJ’s have the horrid Dana 35 at least I think they do.

On a JK I can’t justify as much nor afford one. From what I’ve been able to gather the 2008+ JK’s come with a Dana 44 rear end Dana 30 front end, really leaving only one axle that needs to be upgraded (at least for my needs) selectable lockers would be great front and rear, but I would rather save the price difference on the rubicon and throw a Detroit in the rear and eventually an ARB up front.

What I don’t know much about, is the difference on T-cases between the Rubicon/non rubicon. I know the rubicon’s have the 4:1 aside from that I don’t know the difference.

Wheelbase from what I gather a TJ unlimited is just over 103 inches and the JK’s are at 116. Not sure how much this will affect my wheeling, mostly just would be concerned with break over.

So basically here is what it comes down to, I jumped on Carl’s rig because Toyota’s are what I know. It was a killer rig and it would go anywhere I pointed it. My problem is I’m just not into the “hardcore” wheeling anymore. The trails I enjoy where just way to easy and no challenge for that rig. I would like to continue to do more mild trails, and be a little more challenged on them.

#1 priority I want something that I don’t feel needs to be trailered. I want something that feels very drivable. I want enough power that I’m not going 35 up Spanish fork and a trip to hole in the rock doesn’t feel like I’ve been on the road for a week.

I want something I can fit four people in with enough gear for a day. I want to be confident enough to drive to the Rubicon since I was really bummed on missing the trip this year. I don’t need crazy build. Rubicon, hole in the rock poison spider, heck even just bull canyon are more my cup of tea these days.


I feel the JK with the 4 doors would be more comfortable and easier to access stuff. That being said TJ’s are a lot cheaper and a lot more cash could be thrown at gas and upgrades

Please discuss pros and cons to each, I feel they are pretty close aside from the two doors. I’ve never seen in the back of an unlimited so I can’t compare the cargo room to a JK. I feel the JK cargo area would be sufficient for my needs.

Thanks for the help!


Edit forgot to add, will only be buying an Auto, so if there are major differences and concerns for either please note

 

[Greg]

Just one aspect to consider... the JK has longer 'stock' control arms versus the TJ, so it will ride better on and off the road, especially with a bit of a lift. It doesn't sound like you will be adding any long arm suspension to either vehicle, so IMO that is a pretty important consideration.

I think a 3.8 JK geared like a Toyota will be OK....

 

[TRD270]

Just one aspect to consider... the JK has longer 'stock' control arms versus the TJ, so it will ride better on and off the road, especially with a bit of a lift. It doesn't sound like you will be adding any long arm suspension to either vehicle, so IMO that is a pretty important consideration.

I think a 3.8 JK geared like a Toyota will be OK....

Did not know that, thanks for the input Greg

I'm out of the loop on Jeep stuff, I haven't had a Jeep for about 15 years, and back then all I could afford was a Cherokee even though I really wanted a wrangler.

 

[TJDukit]

I could be wrong but I'm pretty sure the LJ(TJ unlimited) is going to have a Dana 44 in the rear with the 30 up front. If you got a JK the JK front 44 isn't much better than the 30, same knuckles, same tubes just larger R&P. The inner c's on the JK are pretty weak and need to be upgraded which isn't a huge deal with the gusset and sleeve kits that are on the market.

One thing to look out for on the JK is a few of the early '07s slipped out of the factory with the 35 in the rear, very rare but they did happen.

I'll second what Greg said about the longer arms, the JK is neither a short arm or long arm they are more of a Mid arm as people call them. Highway ride is far better than my TJ ever was.

Like you have seen with mine you need minimal lift to fit 35's. TJ's need to have quite a bit of lift to clear even 33's compared to the JK. My TJ had maybe 3" of lift I'm guessing and I still rubbed sheet metal against tires quite a bit. 3" on a JK will clear 37's easily with minor trimming.

Even with stock gears with the manual I still get 16mpg average for the most part. I got 20 on the way back from HITR.

The regular TJ t-case NP231 is a solid t-case. A lot of people doing V8 swaps don't swap them because they can handle some serious abuse as long as they are taken care of. I don't know much about the Rubi cases other than the 4.1 gears which is very nice.

The LJ wheelbase is probably the perfect wheelbase. Sometimes mine is just too long, I do end up getting hung up quite a bit on silly stuff. I wouldn't give up the extra storage space though.

On the trail if I didn't have the Rubi I would seriously miss my 4.0L with the auto. Low end torque is seriously lacking with the V6, with an auto though and the correct axle gears I would say that the stock non t-case in either rig will be just fine.

Ok I'm sure I'll think of some more later and there are probably people more qualified than I but that pretty much sums up my experience going from a TJ straight to a JK.

 

[Cascadia]

Tj's come with the rear 35. Lj's come with the 44 rear just like the jk's. I loved my LJ and would buy another if I could. It had more than sufficient cargo space and I had 4 people most of the time. I thought the short arm ride was fine but it was so much better with long arms.

I had 37's on my LJ with a 2" lift with long arms and hi fenders. I loved the setup. Lots of flex, big tires, with a low belly. I got about 15 mpg with 4.56 gears around town and 20 on the road. And that's with 37's. I was mad at the time with my mileage and that is mainly why I sold it. Only to realize 2 months later that I never calculated in the larger tires for my mileage. Big difference!

 

[Cascadia]

You be me to it.

 

[DerekM]

All the TJ unlimiteds have a Dana 44 rear and it was an option on the shorter wheelbase Tj's. I'm in the same boat as you though, I want a JKU badly, but I can't afford one with the 3.6L. My uncle has a 4 door rubicon with the 3.8L and 35's. It struggles going up the point of the mountain with stock gearing.

 

[jeepin4x4james]

Before I bought my LJ I test drove an '09 JKUR (had 107k miles so was in my price range) ---it was so slow and gutless that the only vehicle I can compare it to was my '77 VW Bus. The bus was fun to drive slow (1st gear up Big Cottonwood), the JK just felt embarrassing (I hear the manuals are faster than the autos). It's no wonder so many people are doing Hemi swaps or adding Ripp superchargers and the like. That being said, my LJ doesn't have the 4.0 so no direct comparison, but I've driven many TJ's with the 4.0 and never felt under powered.

It sounds like your needs go more towards the 4-person and cargo area--- so in your shoes I would go with the JKU, the back of my LJ really doesn't feel much bigger than a TJ... Slightly more cargo room, no more leg room. And like Greg said, gear it obnoxiously low and be prepared for less than awesome gas mileage.

 

[DAA]

You've already covered the pros and cons pretty darn well I think.

I've got a TJ Unlimited Rubi, mildly built. It will fit four people with gear for one day, pretty easily. But it sure isn't easy getting the people in and out of the back seat! My next door neighbor has a four dour JK Rubi and we wheeled together a few times this summer with both our families. Every time we stopped I was getting four door envy worse and worse. Where his kids could jump out and jump back in at will, with ease, my kids had to wait for the adults up front to get out and fold/tumble the front seats. And then of course when it's time to roll again, we have to wait for the kids to get in before we can fold our seats back down and get in ourselves. Not really a huge deal, but when you have a four door right next to you and see how much easier it can be, it starts to seem kind of old. And for kids it isn't too bad gettting in and out, but for adults, it's a genuine PITA getting in and out of that back seat.

I guess what I'm saying, is I think having four doors would be pretty sweet .

I'm married to my Jeep though. Just too deep into it. Not any chance of me getting a new JK (and I personally wouldn't get one without the Pentastar at this point, making it even less likely to happen...). So, I'm happy with my TJ Unlimited and plan on keeping it basically forever.

Don't know if you would even want to, but if you want to check mine out, take it for a spin or whatever, you are welcome to. I'll be driving it to work in SLC (off of Bangerter and 2100 S.) on Thur. to get it inspected, if that's easier for you to get to.

- DAA

 

[gertsch]

I'm 6' 7" tall and fit in the back of lj's rather nicely for long rides. My but has 35's on 3" lift in his rubi Lj and its amazing how well that thing climbs.

 

[TRD270]

One thing to look out for on the JK is a few of the early '07s slipped out of the factory with the 35 in the rear, very rare but they did happen.

I'll second what Greg said about the longer arms, the JK is neither a short arm or long arm they are more of a Mid arm as people call them. Highway ride is far better than my TJ ever was.

Good to know, I was under the impression all 07's had the 35

Tj's come with the rear 35. Lj's come with the 44 rear just like the jk's. I loved my LJ and would buy another if I could. It had more than sufficient cargo space and I had 4 people most of the time. I thought the short arm ride was fine but it was so much better with long arms.

All the TJ unlimiteds have a Dana 44 rear and it was an option on the shorter wheelbase Tj's. I'm in the same boat as you though, I want a JKU badly, but I can't afford one with the 3.6L. My uncle has a 4 door rubicon with the 3.8L and 35's. It struggles going up the point of the mountain with stock gearing.

Also good to know, this opens my options up a little on finding a TJ Unlimited

Before I bought my LJ I test drove an '09 JKUR (had 107k miles so was in my price range) ---it was so slow and gutless that the only vehicle I can compare it to was my '77 VW Bus. The bus was fun to drive slow (1st gear up Big Cottonwood), the JK just felt embarrassing (I hear the manuals are faster than the autos). It's no wonder so many people are doing Hemi swaps or adding Ripp superchargers and the like. That being said, my LJ doesn't have the 4.0 so no direct comparison, but I've driven many TJ's with the 4.0 and never felt under powered.

It sounds like your needs go more towards the 4-person and cargo area--- so in your shoes I would go with the JKU, the back of my LJ really doesn't feel much bigger than a TJ... Slightly more cargo room, no more leg room. And like Greg said, gear it obnoxiously low and be prepared for less than awesome gas mileage.

The power on a JK pre 2012 is concerning for me, the 4 seat access isn't a HUGE deal, as one of the reasons I want a jeep is because my favorite part of having one is topless wheeling. That being said the back seat will mostly be used for gear storage and on those topped trips it is a heck of a lot easier to access through 4 doors

I'm married to my Jeep though. Just too deep into it. Not any chance of me getting a new JK (and I personally wouldn't get one without the Pentastar at this point, making it even less likely to happen...). So, I'm happy with my TJ Unlimited and plan on keeping it basically forever.

Don't know if you would even want to, but if you want to check mine out, take it for a spin or whatever, you are welcome to. I'll be driving it to work in SLC (off of Bangerter and 2100 S.) on Thur. to get it inspected, if that's easier for you to get to.

- DAA

Thanks for the offer! I may take you up on it when the 4runner is actually gone not pending. Knowing the "LJ" has a 44 in the rear makes that option a whole lot more interesting.

 

[TRD270]

One other thing I just thought of.

Do either have steering, frame, death wobble, electrical issues that would sway you one way or the other?

 

[TJDukit]

I would say that death wobble is about the same with either of them as with any coil suspension solid axle rig, one easy fix for the JK is replacing the track bar bolts with SAE bolts because the holes are slightly larger than 14mm, a lot of people including me have replace all suspension bolts with SAE. I've never heard of any frame issues with either. Steering linkages are pathetic at best for both but there are plenty of options for about the same price.

Over 40K on mine and no known electrical issues for the JK, over 70K on both TJ's I had and no electrical problems for either.

 

[I Lean]

The JK will make you happier, I predict.

I actually wouldn't worry too much about the 3.8L power. It's no speed demon, but coming from slow Toyotas, it feels just fine. I spend a long weekend in one driving to Colorado, running trails, driving home. It will hold whatever speed you set the cruise control at, and you just have to ignore the tachometer moving up into the 6K range every so often. Just gear it to the sky and call it good.

The difference between the normal JK T-case and the Rubicon is basically the 4:1 low range. There are a couple internal differences that don't matter, but prevent you from swapping parts from one to the other. The Rubi T-case is a direct bolt-in if you think you need the gearing in a non-rubi JK.

 

[TRD270]

The JK will make you happier, I predict.

I actually wouldn't worry too much about the 3.8L power. It's no speed demon, but coming from slow Toyotas, it feels just fine. I spend a long weekend in one driving to Colorado, running trails, driving home. It will hold whatever speed you set the cruise control at, and you just have to ignore the tachometer moving up into the 6K range every so often. Just gear it to the sky and call it good.

The difference between the normal JK T-case and the Rubicon is basically the 4:1 low range. There are a couple internal differences that don't matter, but prevent you from swapping parts from one to the other. The Rubi T-case is a direct bolt-in if you think you need the gearing in a non-rubi JK.

Always the man with the technical info, I appreciate all the info guys

 

[N-Smooth]

If I was to go to the dark side and get a framed jeep, it would be an LJ. They're the best framed jeep ever made IMO. Perfect wheelbase and sort of rare vs JK's that are freaking everywhere

 

[TRD270]

If I was to go to the dark side and get a framed jeep, it would be an LJ. They're the best framed jeep ever made IMO. Perfect wheelbase and sort of rare vs JK's that are freaking everywhere

Exactly one of the reasons I want an LJ, DAA and TJDukit's rigs are probably some of my favorites...... making this choice very difficult. I lean toward the JKU simply for the 4 doors but I also like the 4.0/two door look

 

[TJDukit]

If I could have my four doors and the 4.0l(for the low end torque) that would be awesome. My V6 is great on the highway though. Even with all the complaints I have against the lack of power I could never go back, but I do have a kid and eventually want to have another so a two door will not be an option for me.

Carl is right though I think at least with a manual you would be surprised at the power difference between your current rig and a JK, going to HITR when I had to stop and try to catch up I kinda got stuck behind Brandon for a while and his little four banger was killing me on the hills.

 

[mesha]

Don't stress the 3.8 liter. They are slow, but like has been said, better than the toyota you were driving. I did lower gears and 37s and mine runs just great around town and on the freeway. The outers on the JK 30 are going to be 32 spline(27 on the tj). The inners on the JK are 27 spline same as the TJ, but the JK is bigger in diameter. They are going to have the same size ujoint as the TJ although the TJ stock is going to have 297s and the JK will have the better 760, the size is the same. The housing on the JK has more problems.

My JKU with stock arms rode about the same as my TJ with long arms as far as smoothness.

The rubicon JK is even stronger than the TJ rubicon front axle, with 30 spline inner and 32 spline outers. The outers on the dana 30 and dana 44 JK are not interchangeable even though they are the same spline. The U-joints on the rubicon are bigger(1350/760 hybrid size). The housings on the rubicon JK 44 are weak just like the dana 30 jk axle. They will need some love if you plan to wheel them hard.

I LOVE TJ unlimited rubicons. love.

I ended up going with the JK unlimited. I loved the 4 doors. I then got rid of it cause I didn't really need 4 doors. Then I bought another one with 4 doors cause I really missed the 4 doors.

Having 4 doors and a removable top is so nice. I have kids and it makes it much more convenient. There is plenty of room for cargo and the JK rides very nice. I ended up with a JKU rubicon because the deal was right and I didn't want to mess with t-case gears and lockers. If I didn't have kids the TJ unlimited rubicon would be the rig of choice for me. since I have kids the JKU rubicon won. If I had to choose between a regular TJ unlimited and a regular JKU I would do the JKU.

 

[jeep-N-montero]

If I were to replace my ZJ with any vehicle right now it would be a TJ Rubicon Unlimited, I have always loved them.