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August 2012 Your Jeep Tech Questions

Posted in How To on August 1, 2012
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Rubicon vs. Cherokee
I have been looking at ’04 to ’06 Jeep Rubicon and Rubicon Unlimited vs. ’91 to ’96 Jeep Cherokee modified to around the same specs as the Rubicon. Either that I get will eventually have 32- or 33-inch tires with a 4-inch lift. The Jeep will be used as a commuter about 26 miles a day to work and occasional off-roading on the weekend. I have a wife and two teenage kids that will sometimes off-road with me. What would you recommend?
David Porter
Mission Viejo, CA

Man, I am a huge fan of both Cherokees and TJs. Since responding to this question, prices for Rubicons in our area float between $17,000 and $24,000. Cherokees are gonna be much cheaper at between $2,000 for a high-mileage XJ and $9,000 for a rare late-model with low mileage, or maybe an already built-up rig. It’s pretty easy to buy and build an XJ that will be every bit as capable as a Rubicon TJ or LJ (’03-’06 Unlimited) and only spend $10,000 to $16,000 total. I’d look for a ’95 or newer XJ (including the ’97-’01 newer body style XJs) with a high-pinion Dana 30 front and a Chrysler 8.25 rear axle (look for a flat bottom edge on the Chrysler axle), low mileage, and no rust. The XJ axles are going to be almost as strong, if not just as strong, as a Rubicon’s Dana 44s. The XJ is probably going to get better gas mileage on-road, but a TJ or LJ may be more durable if used hard off-road for several years. This is because the XJ has a lighter, yet weaker integrated Unitbody chassis, while the TJ/LJ has a true rectangular-boxed frame. Also the top is easy to remove and or replace on a TJ/LJ while a bit more difficult on an XJ. An XJ or a ’03-’06 Unlimited are going to have the extra space that you may want with two teenage kids bopping around. An XJ is the only one with the option of four doors, but if you want a manual transmission you may have to spend some time looking as the later year-model XJs with five-speeds are relatively rare and many with the manual seem to be two-door models.

Gator Aid Tech Tip
I have a tech tip I want to share. If you have an early model NP231 with the factory slip-yoke (like in a YJ or early XJ) and break a rear U-joint and don’t have a spare or don’t have the know-how to change it on the trail it, you’ll have to pull the rear shaft and limp out in front-wheel-drive. This leads to yet another problem, namely that of your T-case fluid running out where your yoke provides the sealing surface. A simple and cheap fix is to use the lid of a 32oz. Gatorade bottle. The output shaft fits right into the inside of the lid so it can spin freely without rubbing the lid; the lid puts just enough pressure on the seal to hold your fluid in without damaging the boot or seal. I hope this helps someone as it has helped me before.
Jeremy Ward
Summersville, WV

Jeremy, cool tip. We’re happy to share this tip, and heck, we may just keep a 32oz Gatorade cap in our tool bag from here on out. This may also work with NP242s, NP249s or NP247s with the similar tail cone. Wait, do you work for Gatorade?

Disconnected
I’ve got a question I need answered. On my ’95 YJ, I installed the JKS Quick Disconnects and it was great. Now, I have the JK and when I installed my Rancho 5000s, I noticed that if I installed them on the JK the springs could unseat and pop out. Is this possible? I enjoyed the extra travel on the ’95 and want it on the JK. Thanks for your input!
Ron Peterson
Via email

Ron, you won’t be able to reuse the YJ disco’s on your JK, but the company does make disconnects for your newer Jeep, and you don’t have to worry about a spring falling out. The JKS Quick Disconnects for JK Wranglers are 0-2-inch-lift (PN 2030) and 2½-6-inch-lift (PN 2034). I’ve had good results with all of the products I have used from JKS, and I feel that their Quick Disconnect sway bar links are some of the easiest to use.

Manuel or Otto?
I’m in the process of restoring a ’94 XJ Country. While not a diehard off-roader, I do plan on some easy-to-medium ventures off the beaten path, and maybe some mild rockcrawling. My question is which is better for off-roading, an automatic transmission or a manual? I’ve never come across any sort of definitive answer. In case it helps, I’ve driven a stick since I was 14 and have a stick for a daily driver, so no worries about suggesting a manual (if that’s the proper answer).
Nate
Marlborough, MA

Nate, this is probably gonna be like poking a hornet’s nest with a stick. Here we go! There are lots of opinions on both sides of this argument and several valid points for both. I guess the only correct answer is to drive and build your Jeep with what you find most comfortable when you are behind the wheel. Since you asked, here is my opinion: I generally prefer manuals off-road. A manual is more resistant to trail damage. A manual can still get you off the trail if you hit a rock and all the gear oil drains out. In auto-tranny-land, being a quart low on tranny fluid can leave you stranded on-road or off. I also like the clutch pedal. You can clutch out of a wheelstand on a steep climbs, while in auto-tranny-land you may roll over backwards while fussing with the brake pedal and reverse lockout switch of a stock shifter. You can also rev up the engine and dump the clutch at high RPMs in a manual, which can be useful in some situations (although this can also blow up parts—ask us how we know). Compression braking in a manual is also a wonderful tool to maintain traction when driving carefully or backing down steep hills. Okay, so some autos with modified shifters can be easily shifted into Neutral or even Reverse on steep climbs. That’s cool—stock shifters are designed to prevent this so you don’t accidentally shift into Reverse on the highway. That’s still a danger with a modified shifter.

Now, having said all that, an auto is generally much easier on axleshafts and T-cases, and the torque converter-slip allows for easier out-of-the-box rockcrawling with less gearing. Also, autos will up shift or down shift when necessary, when the same might be difficult if not impossible in a manual. That can be important in mud, in certain slick climbing situations, and in sand. Desert race off-road trucks run pretty much exclusively auto trannies. That says something for anyone building a Jeep as a prerunner.

Some would argue that an auto is easier to drive with less footwork. I think the footwork is about the same in technical off-road driving after spending lots of time in both. With an auto you use both feet, right on the gas and left on the brake. With a manual you use both, too—right foot on the gas, left on the brake or occasionally the clutch. Hell, honestly, I’ll still drive both off-road, but hey, I am a manual tranny guy and I may never change. It’s hard to beat the torquey feel of a granny-geared Jeep in 4-Lo four-wheel drive.

Does This Winch Make My YJ Look Saggy?
First of all, great job in all you do at Jp magazine. I own a stock ’91 YJ Wrangler with the 2.5L four-banger and five-speed. It has the original leaf spring suspension. I am running 215/75R15 M&S tires. I use the Jeep as a daily-driver here in Big Bear, California, with very little four wheeling.

I have a Warn M8000 winch that I want to add to the vehicle. My question is whether the stock suspension will handle the extra weight of the winch? Also, I wonder if a simple add-a-leaf would be sufficient or should I go with new springs? I do not need to lift the vehicle. I am more concerned about weight carrying capacity. Any suggestions or advice is appreciated.
Skip Stein
Via email

Skip, the front springs will sag about 1-inch with the new winch. They shouldn’t be in any danger of bending, but you will lower your ride height. The 215/75R15 tires you’re running will still clear. You could search craigslist and other on-line sites and find a set of factory rear Wrangler leaf packs (that are same length as the front and have a centered spring bolt). The rear packs have five leafs and the fronts have four leafs. That should give you a little weight carrying capacity.

Or, you could pull apart a Wrangler spring pack and create your own. Take the used main leaf and put it in a chop saw to cut off the spring eye ends, then place it under your factory main leaf.

Or, you can check crownautomotive.net for some stock replacement five-leaf rear springs that you can install on the front of your Jeep. Crown doesn’t sell direct, but it’ll have a list of distributors on its website that do.

WJ Axle Up-grading
I would like to swap out the Dana 35 rear axle in my WJ. I was hoping someone could tell me the width of my current axle, widths of some good prospects, and where I could buy the mounting brackets. I would prefer a Dana 44 but not the Dana 44A.
AKRobert
Via jpmagazine.com forums

The Dana 44A under our ’01 WJ is just under 64 inches WMS-WMS, and we’d guess your Dana 35 is pretty close to that. This means that you can pretty easily swap in a full-width half-ton truck rear axle without having a much wider rear axle. A ’78-’79 full-size Bronco or pre-’82 F-150 should have a Ford 9-inch that would be pretty close to the correct width at 65 inches. Look for a Camper Special model or a 4x4 to ensure the better 31-spline axleshafts. A Ford 9-inch is super strong and infinitely upgradable, but won’t have provisions for the ABS/speed sensors out of the junkyard. The same is true for the very strong rear Dana 60 out of a truck, or the nearly bulletproof, yet huge (read low ground clearance) GM 14-bolts. Both of these axles will have eight-lug bolt patterns and may be wider than a Ford 9-inch. A JK Dana 44 would be a pretty good upgrade, too; it’s a little wider, and has the same bolt pattern as the WJ and should have provisions for the ABS/wheel sensors so that your CPU does not freak out and your gauge cluster won’t light up like a menorah at Chanukah.

The rear upper wishbone will be the toughest part to deal with during the swap with any of the above axles. You will need some sort of truss or bridge to get the upper wishbone mount centered on the top of the axle if you use an axle with a cast centersection. If you use a Ford 9-inch you can weld a bracket right on the stamped steel housing. You should be able to find upper and lower brackets to work with your WJ’s suspension via a Google search. Iron Rock Off Road (ironrockoffroad.com) also sells JK axles ready to swap in your WJ. I am sure Currie Enterprises (currieenterprises.com), and Dynatrac (dynatrac.com) as well as other custom axle builders would be willing to sell you axles that will work in your WJ, too!

Mo’ Mopar Power Fo’ a TJ
I am currently reading an older article called “Taking a Four Cylinder TJ to V-8 Power” by Verne Simons. I am planning on doing this very swap, with either a Chrysler 318 or 360. Hopefully a 360, but really whichever I can find cheaper. My question is that I’m not finding very much info on this swap and I want to do something different than just the normal 350 Chevy swap. Do you guys know where I can find some more info on doing this swap? Also I was looking at hotwire.com for a harness but they are asking $1,400 for one, which seems a little high to me. Maybe this is because this is not that popular of a swap? Is it worth spending the money or should I just match up the harnesses myself? My last question is what would you recommend for a manual tranny? I’m thinking an NV4500 is overkill for me, so maybe a NP435 would be better? Will the NV3500 handle around 300-350hp? This will no longer be a daily driver just plain old weekend warrior. It won’t see much rockcrawling around here, just mud.
Nate
Via email

Wow man that was a while back! If I remember correctly Rob Hall, then working for Advance Adapters, did the swap in his ’97 SE TJ. He basically bought both the factory service manual for his Jeep and the year make and model matching factory service manual for the truck he pulled the 318, NV3500, CPU, and engine wiring harness out of. He then used both books to swap pins, trim wires, splice, and graft both factory wiring harnesses together and basically mate the SEs stock harness to the truck’s engine harness and CPU. Read: lots of work and time requiring good wiring skills and the ability to read wiring diagrams. Since then, Ali Mansour has done a similar swap putting a 5.9L and auto from a Durango in a TJ (“Jeep Wrangler TJ 5.9L Magnum V-8 Swap” Part I, July ’11, Part II, Aug. ’11). Mansour used a harness from Hotwire Auto and honestly that would be the easier yet more expensive method. It really depends on what your time is worth to you. Also be ready to spend $60 to $100 each for factory service manual needed. If you are keeping this thing as a trail rig you probably won’t need an overdrive, so spare yourself the weight and expense of a NV4500. The NP435 would be a good option if you could find one with the low first gear ratio. The NV3500 may hold up to the power, but again, you don’t need the Overdrive, so why bother with a weaker tranny without the granny gear.

Tired Dana 35 Question
OK, I’m not asking the 33-inch tires on Dana 35 question. What I am hoping for is your opinion on what I should do with my TJ. It’s a 4.0L with a five-speed and 3.07 gears. It’s set up with a 2-inch budget boost, winch bumper, winch, and steel tube fenders riding on worn-out 31-inch mud tires. The front end is starting to sag and I have a remedy for that, but my question is, once it’s level, are the 31s gonna look way too little? It really needs 33-inch tires to finish the look. Here’s the problem, I’ve got four kids with two brand new twins. This next set of tires has to last awhile, so 31s or 33s? I won’t have the cash for a re-gear but I don’t get to wheel that often anyway, so I think I can handle the 3.07s and 33s (I think). What would you do?
Jason
Via email

Jason, I am currently putting lots of miles on-road and off- on a ’97 TJ with a budget boost and 32s. This combo is just about perfect in terms of height/tire size in my opinion. Honestly the 3.07s would be too tall of an axle gear for much of the wheeling I do on the 32-inch tires even with the Jeep in low range, but my TJ is a four-cylinder. The torque of your six-cylinder may help counter this, but I can’t make any guarantees and unfortunately an axle regear generally goes hand in hand with bigger tires. I would keep my eyes peeled for some stock TJ axles from a four-cylinder with 4.10 gears or 3.73-geared axles from a TJ with an auto and the 30-inch tire package to stay budget friendly. Sure you’ll still have a turd of a rear axle in the Dana 35 (you may find a 3.73 geared Dana 44 rear), but the lower gearing will make a big difference for your Jeep off-road even with an open differential and you can sell your old axles or keep them for parts.

Murderous Spring-Over-Kill
Hi, this is my first post, but I’ve enjoyed reading a bunch of everyone else’s on jpmagazine.com forums. My son and I are starting work on a ‘49 Willys pick-up. The body’s in pretty good shape. We found a Dana 44 for the front and an Eaton with a Detroit Locker for the rear. We need to know what would be good springs to set it up with. We were thinking a spring-over with enough lift for 35’s. It will end up being a daily driver for him in a couple of years when he’s 16. Anyone out there have any ideas?
Lloyd Rutherford
El Dorado, CA

Lloyd, check out “Project Murderous Overkill” (Feb. ’09). Christian used some Rancho 2.5-inch lift Wagoneer springs (PN 44044) and it should be very similar to what you are building. Also, in my experience spring-over is great in the front offering tons of flex, but can have undesirable side effects in the rear. You may look into having higher arch springs out back with a spring under suspension set-up. This will help reduce the chances of problems with axlewrap during heavy acceleration and hill climbing. Otherwise you may have to figure out how to build a traction bar. Building a traction bar that stops axlewrap but does not limit flex is difficult. By the way, that’s gonna be one helluva daily driver for a 16-year-old.

Write Us!
Got a tech question you’re just itching to get answered? Send it on in to Jp magazine, Your Jeep, 831 S. Douglas St., El Segundo, CA 90245, or e-mail it to verne.simons@jpmagazine.com.

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