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Building an LJ for cross country


60cyclehum

New Member
Joined
Jul 2, 2020
Messages
11
Location
Ky
Hello all,
Just got my first Jeep, 04 LJ.

In the process of going through it, to fix anything that needs it.
Front suspension/steering needs attention, it’s tight, but have split boots on most joints, so failure is just a matter of time.

The big question- is lift. Which could change some of the parts I would need to replace, so I need to figure that out.

Here’s what I’m shooting for: reliability, best high speed handling I can get, and the ability to handle upper medium difficulty trails.

I’ll be using this as a daily driver. Some of the trips I’ll take will log 5000 miles at once, so the ability to be able to drive 80 safely and confidently on the highway is very important.

I’d like to keep my center of gravity as low as possible to help with high speed handling.
Right now I’m thinking I might be able to get away with tube front fenders, minimal lift (maybe only 1” if possible) and 33” tires, probably duratracs, which I like. Maybe 17” wheels to help with highway manners, and larger brake possibility. It has the stock wheels and 31” currently.

No experience with jeeps, and this forum has a wealth of knowledge , been reading it constantly. I’m sure someone on here has set up a TJ similar.
 

Goatman

TJ Expert
Supporting Member
Joined
Apr 23, 2019
Messages
4,115
Location
Upstate NY
2 1/2" OME springs and either their Nitro Sport or Rancho 5000x (0-2" lift) and run 265/75R16 or equivalent (32 inch) tires is a very solid setup for 'overlanding' or long camping/roadtrip. If you want 33s just add a 1 1/4" body lift. Otherwise you can have a lot of rubbing and loss of articulation. Spring rate depends on how much weight you are planning on adding. Armor, winches, bumpers, camp kitchen, they all add weight. Please keep us updated on your build and adventures. Remember to add pics.👍
 

Hopper

TJ Enthusiast
Joined
Dec 28, 2018
Messages
269
Location
Georgia
You could keep your suspension the same and with 1.5 or 2 inch coil spacers, rancho shocks as advised above with 32s 265/75r16. This will keep your jeep driving pretty much like it does stock and add a little hight on the trail. To add 33s you could do the body lift and check your bump stop. May want to add some traction control aswell locker or no-slip. No slip in the rear and locker up front is good for street and highway and will only be noticeably different when you put it in 4x4.
Or just go all out and do the OME as above.
 

AjRagno

TJ Enthusiast
Joined
Dec 27, 2019
Messages
197
Location
MN
The OME Ultimate Kit with OME shocks would be the best handling kit, particularly if you are carrying extra weight.

Forget about 17” wheels on a TJ, 15” are perfect.

The Duratrac is great tire (I ran a set for about 85,000 miles), but they do not handle well in mud and the sidewall is vulnerable to rocks and sticks. The K02 is better in mud, has improved sidewall protection, and also runs slightly better on the highway (smooth and quiet).

If you are going to run a 33” tire, you will absolutely have to re-gear the axles as well, ideally to 5.13.

33x10.5 tires will stress the axles less than 33x12 and you can continue to run stock wheels.

If you are going to leave pavement, you’ll want a transmission cooler and temp gauge to ensure the transmission does not get too hot.

Don’t have $5,000? Get some H&R 52107 springs and stick with 31” tires. Any time you’re traveling far from home, reliability needs to be top priority.

 
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60cyclehum

New Member
Joined
Jul 2, 2020
Messages
11
Location
Ky
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It’s not much to look at- yet. Stock, so I’ve got a blank canvas. Bumper plastic corners were removed immediately the next morning!
Was looking for black, dark blue, dark green...but finding an LJ was tough and I was in a hurry. The red is ok, pretty classic looking.
I was wrong on the tires being 31”, they are the stock 30/9.5 (which actually measure 29”, I checked).

I don’t like adding weight to vehicles when it can be avoided. I will however, add a front winch. I’ll go as lightweight there as I can, without compromising strength. I’d like to remove as much weight as I can! Backseat will be out most of the time, and doors off as much as possible.
 
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60cyclehum

New Member
Joined
Jul 2, 2020
Messages
11
Location
Ky
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Gotta love this 2 door Jeep! Camping box, 2 chairs, 2 tarps, cooking box, 2 coolers, tent, comforter, blanket & 2 pillows, axe, shovel, backpack, air mattress & pump.
Room to spare!
 
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60cyclehum

New Member
Joined
Jul 2, 2020
Messages
11
Location
Ky
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I already have 4 17” duratracs. 285/70/17. Looks like the Jeep would definitely need a little bit of lift to get these on. They sure would be awesome though!
Believe it or not, I had these stuffed onto a Lexus gx470 with zero lift! Found FJ cruiser wheels with more negative offset, and got them on. A little rub at full lock occasionally, but no problem- put 50,000 miles on them that way, with lots of trails in moab too. Did great on the highway at 80/90 (fairly straight road of course) .
The Lexus had 3.73 gears, but also 263hp/323tq. That torque rocked too. But it also weighed 4800 lbs- over a 1000lbs more than the 04 LJ
 

Steel City 06

TJ Addict
Supporting Member
Joined
Mar 12, 2019
Messages
2,829
Location
Pittsburgh, PA
Definitely budget for a regear. Highway driving is much less frustrating when you have the appropriate torque. Forced induction also vastly improves highway performance, but costs major $$$.
 
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60cyclehum

New Member
Joined
Jul 2, 2020
Messages
11
Location
Ky
You guys think 33”s / 3.73 would be that anemic on the highway hills even in 3rd gear with the OD off?
Really not wanting to re-gear, this thing is gonna cost enough just to get up to snuff, and I probably will add a locker.
So these re-gears- what rpms are they hitting at say 80mph?

On the trans getting hot, I’ve read that these autos are lucky to get to 150k or so before needing a rebuild. I’m at 131k, trans shifts fine, and I was planning on doing fluid and filter. Any coolers recommended? A thermostatically controlled one would be nice, as long as it’s reliable.
What about spare tire/rear door weight? Manual says 50lbs max, but I’ll bet the stock is more than that. A 285 duratrac is 54lb with no wheel, wheel should average around 25lb or so. Are the rear door/gate up to this?
Thanks for the ideas guys! This is a tricky one for me! Loving this Jeep- these are problems I like solving!
 

DoOver

Member
Supporting Member
Joined
Jun 2, 2020
Messages
81
Location
So Cal
Depends on your definition of medium to hard trails. The set ups listed will be fine for moderate wheeling but, hard trails as you mentioned will not work.
If I were building from scratch with the goal of medium to hard trails (my definition of hard is Hammers or Fordyce)
high line tube fenders (cutting or replacing the front hood)
1 1/2 body lift
tummy tuck
moderate suspension lift from should accomplish your goal.
 

Steel City 06

TJ Addict
Supporting Member
Joined
Mar 12, 2019
Messages
2,829
Location
Pittsburgh, PA
This calculator is the best resource to calculate RPMs based on tire size and gear ratio for just about any passenger vehicle.


Plug in your tire size and gear ratio. If you subtract about an inch of tire size, it will give you more accurate results due to the rolling radius being different than the unloaded radius.

The 42RLE has a very tall overdrive (0.69) compared to the other Jeep transmissions, and the RPMs run much lower. A stock TJ Rubicon with NSG370 does about 2700 RPM at 70 mph from the factory. That is generally considered a good target. (Many people prefer to target about 3000 RPM at 75 mph with the manual transmissions.)

5.13 gears are the generally recommended ratio for 33s and the 42RLE, and also happen to be the deepest ratio you can get for the Dana 30. 5.13 gears will make driving much more satisfying, easier to pass cars, and easier to hold speed with cruise control.

Deeper gearing will also help the transmission run cooler, as the torque converter remains locked much longer, and the fluid is sent through the cooler more often. An auxiliary cooler is a good idea, especially if you live in a hot area or frequently tow.

If you want to add lockers (or just a single locker), the best time to do so is during a regear. Doing both together saves a lot of labor over doing them separately.
 

AjRagno

TJ Enthusiast
Joined
Dec 27, 2019
Messages
197
Location
MN
On the trans getting hot, I’ve read that these autos are lucky to get to 150k or so before needing a rebuild. I’m at 131k, trans shifts fine, and I was planning on doing fluid and filter. Any coolers recommended?
I’m 245,000+ on my 42RLE. I got here in part by not running large tires with 3.73 gears. The 42RLE is entirely electronically controlled. Beyond the clutch packs, there are no parts to wear out. Keep it cool and don’t stress it with improper gearing.

Derale makes a really good cooler with a fan but anything helps. In day to day driving you’re fine. It’s when you can’t maintain TCC lockup that things really start to heat up.
 

MountaineerTom

LJ Enthusiast, Retired USAF Weapons Loader
Supporting Member
Joined
Sep 25, 2018
Messages
2,431
Location
South Carolina
I used a simple B&M stacked plate cooler mounted behind the grill. Temp gauge in the center console and temp sensor in the pan.

 

Jeffreybomb

Póg mo thóin!
Supporting Member
Joined
Jul 1, 2017
Messages
784
Location
Chicago, IL
I'm surprised it hasn't been asked (or maybe it was and I missed it): do you have cruise control? These things aren't aerodynamic at all. Driving 80 miles an hour with any kind of crosswind will range from "annoying" to "holy shit I'm arm-wrestling a mechanical bull".
 
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JPHikr

New Member
Joined
Jun 27, 2020
Messages
5
Location
East of Nowhere
I too just got a TJ after looking for two years for exactly the one I wanted. A rust-free unmolested Rubicon Hardtop top Unlimited in white with auto trans.

It was a 600 drive to go pick it up from the 72 yo second,who ten years ago spent 6 months looking for it to purchase.

He had driven it 50000 miles in the ten years he had owned it, the total mileage on it was 111,000 when I picked it up. He swapped the which on to his LR four door as part of the deal.

My drive back from Nevada to Arizona was down the 395. With all of the mountain pass I realized the 265-85/16 BFG were to tall even with the 4.11 gears and I was taking it out of OD when climbing the passes.

As soon as I got back I replaced the BFG's with Duratrac's in 265-75/16 this is the same size that I have on my 1980 FSJ and my C-20, what a difference no more constant down shifting climbing long hills.

My plan is to install a heat sink trans cooler on the front bumper in place of the winch and also put a spin on Baldwin B7 filter on the trans lines so I can change 20% of the Royal Purple ATF every time I do an oil change.

As for driving at 80 mph good luck with the aerodynamics of a brick any side gusts of winds you will be more than likely rolled over in the ditch. I have drive it in side winds of over 50 mph at 55 and it is a wee bit scary.

Good luck with your build. I have read nearly 500 pages of post on this forum and there is a lot of good info here.

Jeep 1.JPG
 

en480c4

New Member
Supporting Member
Joined
May 30, 2020
Messages
21
Location
York, ME
I’m running OME ZJ V8 934 coils in front and LJ HD 949 coils in the rear of my LJ with 285/70R17s. Netted exactly 3” F & R and my KO2s measure exactly 32”. Very pleased with how it turned out... I know a lot of people think the OME shocks are too firm, but I like the ride. And I’ve been fine with the auto with OD turned off, though I recognize terrain makes a big difference.

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60cyclehum

New Member
Joined
Jul 2, 2020
Messages
11
Location
Ky
This thing sure has been keeping me busy......
Changed oil/filter and cleaned oil pressure sending unit (low pressure light went off and scared the hell out of me!) all good now, been 800 miles without that happening again. Not fond of the pressure gauge. Would like a real one.

Had a coolant leak, I determined was the water pump, so rebuilt cooling system- new radiator, water pump , thermostat, pressure cap, rad and heater hoses. Went with mopar rad and pump, gates hoses and stant thermostat and cap. No more leaks. Threw a new belt and idler pulley on also.

Bought a set of 17” wheels to mount the duratrac 285/70/17 tires I already had. Went with 3.75 backspace, -24mm offset.
Worked beautifully- I honestly thought I would mount them and then have to take them off due to clearance issues, but to my amazement- they are totally fine with no rubbing even at full lock. Off-road obviously will be different, but I’ll test that out soon and see how much extra clearance I’ll need. Flares are gonna be an issue for sure.

Also replaced broken sway bar links, iac and removed and cleaned throttle body, changed front diff fluid, and got 4 new bilstein 5100 shocks. Put the fronts on and they make a huge improvement. I added about 30lbs of unsprung weight at each corner (which I hated doing!) and these shocks control the rebound of the heavier tires/wheels much much better.

Not to mention much underbody and engine cleaning, all ground connections I could find, and tons of electrical connectors.
Much more work to be done, but it’s definitely improving!
 
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60cyclehum

New Member
Joined
Jul 2, 2020
Messages
11
Location
Ky
And jphkr, good luck with your LJ! I love the hwy 395 through the Owens valley. I’ll have this LJ in Death Valley , some winter soon, maybe this one.