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May 2013 Techline

Posted in How To: Tech Qa on May 1, 2013
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Dual Purpose
I have a '68 Chevy K10 longbed that I have had since I was 16. Over the past several years I have been gathering new parts. My plan is to use the truck mostly as a farming, fishing, hunting, and work truck, so drivability is very important. It currently has 327ci V-8, SM465, Rockwell transfer case, 52-inch front springs, 63-inch rear springs, dualie Dana 60 front (needs rebuild), 14-bolt rear (needs brakes), and 37x12.50 tires on 16.5-inch H1 rims. I plan to do some mudding and trail riding, but no hardcore off-roading by any means.

I read the specs on Cappa's FSJ truck and want to get close to that setup. I'm currently in Afghanistan (I don't have a lot of access to a computer and my wife is slowly sending out all my off-road magazines). I am on a budget (like everyone), and only able to afford one locker during this build-up round. I have two questions. Will the factory stub shaft and U-joints be okay, or should I upgrade to factory-spec alloy replacements? I don't think I need the 35-spline upgrades on this build.

My second question is: Which axle should I put the locker in first, and should I go with a selectable up front and automatic Detroit Locker in the back? I got a Dana 60 for $600 with missing spider gears, so I was thinking about the Eaton E-Locker this time around since I have to get it re-geared and build it anyways. I will eventually make this truck into an off-road only vehicle. I spent many years in Twentynine Palms fixing my truck and other peoples play toys, so I understand that I cannot push this truck too far, and what a dedicated off-road truck needs. I've never built a dual-purpose truck before and would like some advice. I need to get this truck up and running so I can take down my son's CJ-7, rebuild it together, and start driving it in a couple of years.
David Wright
Via email

Your first and second questions are definitely interrelated. If you put a locker in the front axle, you will be more likely to break an axleshaft over having an open differential. Upgrading the axleshafts isn't a bad idea, but don't feel as though it is an absolute must. If you are on a limited budget I would toss in a new set of spider gears in the front and call it a day for now. The performance advantages of a rear locker almost always outweigh those of one in the front.

With that being said, I suggest using an automatic locker, like the Detroit Locker or Grizzly Locker, into the rear of your truck. An automatic locker is a more budget-friendly option and will not require any extra plumbing or switches to operate. The downside is that they will have a few handling quirks that you'll have to get used to on-road, but nothing that would keep you from daily-driving your rig.

Will Work Four Wheel
I was wondering how I could work for Four Wheeler magazine? I am 16 years old and it's my favorite magazine.
Dilyon Burgoyne
Via email

To land a job at Four Wheeler you'll need to be proficient in writing, photography, and time management. Beyond that basic skill set, you have to be a genuine off-road enthusiast, as your life will revolve around everything 4x4 and off-road related. I grew up in and around automotive and fabrication shops, earned a writing degree in college, and have been an off-road enthusiast for as long as I can remember. Even with all of the aforementioned, it was a stroke of luck and great timing that allowed me to get my start as an automotive journalist in 2007.

As a monthly magazine, we work within tight deadlines. And while it may seem like we are living the high life and wheeling every weekend, it simply isn't the case. The pay is marginal, the hours are long, and the expectations are always high. I'm just a lone worker bee, so you'll have to look at the job openings on our corporate website at to see what spots are available. There you will find the precise requirements needed to land a job at one of the many truck magazines. Best of luck!

Hummer Bumpers
Can you help me locate a company that offers steel front bumpers for an '08 Hummer H3 Alpha? I'm doing some upgrades (mild 2-inch lift, 35-inch Yokohama tires, Bilstein shocks), but can't find anyone who makes a winch-ready steel bumper for my truck.
George Her
Via email

Tough Country ( and ARB ( both make steel bumpers for the H3.

Rubi Trans
In the Feb. '13 Four Wheeler article about the 10th Anniversary Wrangler Rubicon you mention that the manual transmission versions were finely tuned with the electronic-throttle pedal. Do you mean that Jeep has upgraded the manual gearbox for the '13 Rubicon model, or did you just mention an already existing feature of the manual Wrangler Rubicon with the 3.6L engine?
Dimitri Papad
Via email

The statement was based on the current model year's pedal reaction and consistency, which felt better off-road than the previous Rubicon model years. The manual transmission gearbox in the JK has been unchanged for 2013.

Death Wobble
My '08 Jeep Wrangler Unlimited has over 100,000 very reliable miles on it, but has developed death wobble to the point where it's no longer safe at highway speeds. A visit to the dealership suggested that I needed tires. After spending $1,200 on new tires, the Jeep still wobbles over highway expansion joints, manhole covers, and bumps in the road. Reading up on the topic has proven that a lot of people have this problem with the '07-'10 Jeep Wranglers.

Because this is such a huge mystery to those who look at it, I would like to ask that you consider a JK death wobble tech article. I will even go so far as to bring you my Jeep- a real world example of a Jeep that is driven every day, as the test mule for the story. Detroit, New York or anywhere along the east coast can be done by me. I drive a lot.
Ted Grevers
Via email

We have written about the possible causes for death wobble a few times. Many of the past articles can be found online at Whenever I experience death wobble, I perform the following trouble-shooting method first. With the vehicle running and in park, lay a couple of feet in front of the front axle. Next, have a friend sit inside of the rig and saw the steering wheel back and forth repeatedly. You are looking for movement or play in an end-link or joint. A loose bolt, nut, or worn suspension bushing can all cause death wobble as well. In my experience, a worn track bar bushing or damaged track bar bracket is commonly the culprit.

Once you have made sure that everything is tight and replaced any worn joints, paint mark the hardware so you can easily see if anything works loose. If you now move the wheel back and forth and nothing appears to be loose or worn, but still experience the wobble, move on to step two which is as follows. Using a floor jack and jack stands, raise and set the front axle off of the ground. You'll want enough space to get a pry bar under the bottom of the tire.

You can sometimes use your hands to test this, but the pry bar will give you a bit of leverage. What you are testing is if there is play at the wheel end, to the point where there is a major camber shift or movement top and bottom. If the camber is changing drastically you'll need to examine the ball joints and the unit bearings. The factory JK ball joints are not the best, and with 100,000 miles on them, I would not be at all surprised if they were smoked. Lastly, be sure your alignment is set correctly and that a shop experienced with oversized tires (assuming your Jeep is lifted) has set it appropriately.

The dealership sometimes misses the mark when it comes to problem-solving modified Wranglers. It's a sad, but common complaint I hear. There is a fair amount of worthy off-road specific shops along the east coast that should be able to help you with your problem if the aforementioned tips do not work for you. Death wobble is not some incurable Jeep disease, but more like a cold that needs the right remedy.

Tread Flippers
I was looking through the November '12 issue and saw that a few of rigs had the tires mounted backwards. I grew up on a farm and know about tractors, even had an '82 Toyota with 31-inch terra tires on it. I did a stint with the Seabees and found out that they put directional tires on the front axle of road graders on backwards because it's not a drive axle. So what's the reasoning on these rigs? Do they think the course is too easy and they will be doing it in reverse?
Brian Daugherty
Via email

Some guys reverse their tires simply to be different, while others swear by the performance advantages of flipping the tread on directional tires such as the Mickey Thompson Baja Claw or Interco Super Swamper Bogger. If you've spent a fair amount of time with a tire groover or modifying a tire, you may be able to create a unique pattern that works better. For the most part, I haven't seen big advantages for running a directional tire in the reverse direction. Some of the Top Truck Challenge competitors swap their directional treads for a given event to actually reduce the amount of traction and bite, in an effort to allow the tire to slip (i.e., Tow Test).

Case Swap
I have a '97 Jeep Grand Cherokee equipped with the stock V-8 and NP249 transfer case. I would like to swap out the stock T-case with a NP242 Selec-Trac T-case. My two questions are as follows. Why were the V-8 Grand Cherokees not offered with the Selec-Trac T-case originally, and what do I need to do to swap one into my Jeep?
Jacob Simmel
Via mail

I actually had a '98 Jeep Grand Cherokee with the 5.2L V-8 and NP249 T-case. While the NP249 is plenty strong, I completely understand wanting to get away from the full-time 4x4 case. I ended up swapping in an NP231 T-case in my Grand as I didn't need the 4-Hi all-wheel-drive feature of the NP242. As for why the V-8 Grand's were not equipped with the Selec-Trac, we surmise that it partially had to do with what Jeep viewed as it's initial-purchase audience and more importantly, for safety reasons. Another important point was that some of the early V-8 Grand's were equipped with a Dana 35 rear axle, so splitting the power helped keep the light-duty differential alive.

As for swapping the NP242 into your Jeep, it isn't a terribly difficult conversion. I suggest finding one with a 23-spline input, which is common on the '87-'01 Jeep Cherokee XJs. There are some variations in the input length, so you may have to swap out the input, which isn't hard, but a service manual will be very helpful to walk you through the process. You may get lucky and find that the input is just a touch long and you can machine some material off of the front for it to mate up.

The six-bolt mounting pattern will bolt up to your transmission, no problem. Your stock T-case shift handle can be re-used and you can likely find the shifter indicator plate from a Grand in a junkyard or online. You'll need to modify the shift-linkage (most likely shorten it), and a new rear driveline is warranted. It may be possible to re-use your front driveshaft. These are the major hurtles of the swap, but there are some smaller ones that will vary from year to year. Overall, it's a worthwhile swap that won't cost you too much dough.

Where To Write
Address your correspondence to: Four Wheeler, 831 S. Douglas St., El Segundo, CA 90245. All letters become the property of Four Wheeler, and we reserve the right to edit them for length, accuracy, and clarity. The editorial department can also be reached through the website at Due to the volume of mail, electronic and otherwise, we cannot respond to every reader, but we do read everything.

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