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October 2007 4x4 Tech Questions - Nuts & Bolts

Posted in How To on October 1, 2007
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Confused? E-mail your questions about trucks, 4x4's, and off-roading tech using "Nuts, I'm confused" as the subject and include a picture (if it's applicable). Digital photos must measure no less than 1600 x 1200 pixels (or two megapixels) and be saved as a TIFF, an EPS, or a maximum-quality JPEG file.

Also, I'll be checking the forums on our Web site (, and if I see a question that I think more of you might want to have answered, I'll print that as well. Otherwise drop it old-school style with the envelope addressed to the address below. Letters published in this magazine reflect the opinions of the writers, and we reserve the right to edit letters for clarity, brevity, or other purposes.

Write to:
Nuts & Bolts
4-Wheel & Off-Road
6420 Wilshire Blvd.
Los Angeles, CA 90048-5515
fax 323.782.2704

E-mail to:

Question: Why is a U-Joint called a U-Joint?
Dave H.
Missoula, MT

Answer: Good question. U-joint is an abbreviation for universal joint, an age-old concept for transmitting power through a shaft with an angle. Every few hundred years somebody reinvents it and it is then named after them such that it has been known as a Cardan joint or Cardan shaft after Gerolamo Cardano in the 1500s. Then it was a Polhem knot after Christopher Polhem, or a Hooke's joint after Robert Hooke in the late 1600s. It wasn't until Henry Ford began making cars that it was christened the universal joint. Most of the people I talked to assume Ford named it a universal joint because it can be used in many different angles and applications in an automobile such as in a steering column, front steering axleshafts, or driveshafts. The universal joint is a strong way to transfer power from one shaft to another at an angle, but often the greater that angle the weaker the joint. This is why it isn't a good idea to force your axles to do excessive climbing or crawling when the front wheels are turned unless you are outfitted with strong U-joints.

Question: Why is a tire called a tire?
Tom Boyd

Answer: A tire is called a tire because if you drive for a long trip on a set of tires, such as the long drive home from a great week of wheeling in Moab, you are bound to become tired. That's not really true, but it sounds good. Actually I think the truth is that tire is a derivative of attire such as clothing or accessories. Thus if you want to dress up your truck you need to find some better attire or better tires. I prefer my trucks to be dressed in something taller than smaller and usually in a dark blackish color with some sort of aggressive treadlike pattern.

Question: Why is a portal axle called a portal axle?
Dylan E
Corona, CA

Answer: Another great question! A portal axle is an axle that has gearing within drop boxes at the end of the axlehousings. These offer increased ground clearance but they also transmit the rotation force of the axle from one level at the axleshafts down to and out the stub shafts at the centerline of the lower gears in the portal drop box as can be seen in these photos of some prototype military axles. In researching the term "portal" I came up with a few definitions. First is one in the construction and architecture industry where a portal bridge or roof of a building has a top crossbeam supported by two legs at either end of the beam, similar to how the axletube is supported by the drop boxes.

Another definition comes from the science-fiction or fantasy literature where a portal is a magical or technologically advanced doorway between distant locations. This could be applied to the driving force being transported from the upper axleshaft down to the lower stub shaft through the portal gearbox. Though I doubt whoever named the portal axle was referring to some space odyssey/magic cave type thing when he was describing these axles.

By the way, I also found a heavy metal band in Canada named Portal, and many portal axles are heavy and made of metal, but the band only formed in the summer of 2000 and portal axles have been around at least since the '40s, if not earlier.

Finally I began thinking about how the power is transmitted into the axle at one level and comes out at another lower level and I realized that it is similar to a periscope in a submarine where you look in at one level and through a series of mirrors you can see out at a higher level. In fact, I think the proper term for portal axles could be periscopal axles, but I'm pretty sure no one would know what the heck I was talking about if I said that.

Question: I have a '77 Jimmy with a 12-bolt rear end, a Dana 44 front end, and an NP203 I think. I am not sure about what gears I have, but was thinking about changing them. Should I put the same gear ratio in both front and rear, or keep them different? If it is better to keep them different, then how far should I keep them apart?

Answer: You definitely want the same gear ratio front and rear, or as close to the same as possible, say within 0.03 points. So if you have 4.10s up front you would want between 4.07 and 4.13 in the rear. The only time you want different ratios front and rear is if you are running different size tires front and rear, but for the majority of folks, or other specified applications running the same ratio front and rear will work best so that the transfer case will not bind when locked in four-wheel drive.

Question: I have an '81 Toyota longbed 4x4. I've really enjoyed your articles on winches over the past months, so I have been shopping for one. However, it seems like all the sales people want to sell you the biggest, baddest winch they have in the showroom! What is the general rule when it comes to matching up a winch for your truck?

Answer: The rule of thumb is the winch rating should be 1 1/2 times the gross weight of your truck. So if your truck weighs 4,000 pounds, you need a winch no smaller than a 6,000-pound rating. To determine the gross weight of your truck, fill it with all the gear you think you'll have with you when you might get stuck-including a full tank of gas, tools, cooler, and so on-and go weigh it at a truck stop or the local dump. Then add a few hundred pounds for whatever winch bumper you might run and then multiply that number by 1 1/2. If you want to be sure add an extra 2,000 pounds to the number you end up with for any future weight gains or upgrades. Just make sure you have enough winch and that it has a good brake because you never know when you might need to winch your truck up a tree to get the tires off the ground so you can reseat the bead which came off while four-wheeling in some mudhole after dark, deep in a rainforest in Australia.

Question: A few years ago my granddad died. He was a champion among men and loved the outdoors, tinkering with trucks, and going on long drives in the woods. He had a two-year subscription to this magazine when he died and I "inherited" the issues as they continued to come in. I was never into anything automotive growing up but when I started reading this magazine I began to really look forward to getting it. Also, it gave me a good reason to go see Ma. Long story, short: I got the bug and went out and bought a '79 International Scout II. I think Granddad would've loved it. I don't have a lot of money (wife, son, and baby on the way). I was hoping you could help me produce a plan to get my rig trail-ready. It runs good. I bought tires and wheels at Les Schwab on credit. Dick Cepek 31-inch Mountain Cat Radials. I'm thinking rollbar/cage for safety is the next step. A winch would be cool. What do I really need? How do I do that cheap? How much should I expect to spend? Can you help me so I can start convincing the wife? Also, I would love a 4-Wheel & Off-Road license plate or sticker. Can you hook me up? I know Granddad loved this magazine and now I know why. Thanks so much for giving me a monthly reminder of someone I cared about and admired so much.
Dan S.

Answer: I know how you feel. My grandfather and father were both the type of guy who could do amazing things with his hands and loved to go exploring backroads of the world. However, somehow I ended up playing with trucks while both of them thought vehicles were more for getting from point A to B. Nonetheless I think you'll make Granddad proud with your Scout, especially if you take it to show your kids and grandkids the great outdoors.

I think you are on the right track with your buildup. There are a few things I would recommend for your Scout and you already have, or are planning to get, three of them. Mud tires are important because they give that traction you need for mountain roads, and a rollbar or cage is very important especially if you are taking family with you. However, let me suggest a rear locking differential such as a Detroit ( or ARB Air Locker ( I run both styles in my trucks and would be hard pressed to pick a favorite between the two as both have offered me excellent performance off road. ARBs cost a little more but offer the ability to turn them off when you don't want a locker such as in icy conditions. Whereas Detroits are usually priced better and are quite reliable. Just be sure both rear tires have exactly the same air pressure when driving on the street so as to not get the locker's harsh street manners. By installing locking differentials you will get power to both rear tires no matter what the traction and often this is the difference between getting stuck and getting through. Along with the locker I would look into lower gearing if you have anything higher than 4.10s in the diffs (by higher, I mean numerically lower; for example, 3.73 is a higher gear than 4.10 or 4.56). With 31s you'll be fine with 4.10s if you ask me, maybe 4.56. I definitely agree that a winch is next on the list. Every single time I have walked home from my stuck vehicle, a winch would have saved the day, so that is definitely on the list of upgrades I would want. As for which winch, I think the Warn 8274 is probably the best you can get for your Scout, though any 8,000- or 9,000-pound capacity winch will be fine.

So what will this all cost? That depends on where you find the parts, how much work you can do yourself, and how long you take to do everything. If you went to a shop and bought a winch, 31-inch tires, a rear locker, and a rollcage and had it all installed I bet it would cost around $3,000 or $4,000, but then you wouldn't know how it all went together. If I were you I would watch the classifieds, spread the work out over time, do it yourself, and take the truck wheeling between each upgrade so you'll learn some off-road driving skills and see what your Scout can do. As for the license plate, I'll see what I can do about sending you one. Good luck and thanks for reading our magazine.

Question: I'm what you call a "noob" to off-roading. I have been with my friends multiple times and enjoyed it. Now I am in position to purchase a 4x4 of my own. I am a college student living at home with my parents, thus allowing me to do as I please with my money. I want to reward myself for completing two years of college and finishing an EMT program.

My problem is I don't know what to get. I would like a nice daily driver that can handle the trails when I go with my friends and go camping/road-tripping from Texas to Colorado regardless of weather. I am also going into the local volunteer fire department. I'd like something that isn't so extreme to prevent me from responding to a scene carrying any rescue/emergency equipment. But I'm also commuting to school from suburbia to inside the loop of the city, so it's a challenge for me to figure out what I can find that is comfortable for me.

I can set aside about $12,000 for a used 4x4 and I could possibly even use a bit of my student loans to write it off as a transportation expense. I need something that is at least a '98 or newer (my Acura is a '97 and my parents won't let me get something older than my current vehicle). I have been looking at three vehicles in particular: the Xterra, late-model 4Runner, or Liberty.

I know this is not a typical question, but I was just hoping for some suggestions and opinions from more educated gentlemen such as yourself. I mean, once I get the vehicle how should I go about modifying it? I'll be holding onto this vehicle for at least like the next 10 years until I'm done with school and hopefully my med school stuff. I don't want to tax you too much from people who may have more serious concerns. But any help or opinions would be greatly appreciated.

My final concern isn't vehicle related at all, but I wonder how to deal with other people on trails. I'm an Asian kid whose well-Americanized, but sometimes on trails with my friends other folks give me a hard time for my race and ask if I should be at some dragstrip or something. It has never gotten physical but almost did. Any suggestions with this as well?

Thank you again for your time, and thanks in advance for any response.
Jimmy Nguyen

Answer: I read your letter like I read all of them and that last paragraph about people giving you a hard time because of your race really bummed me out. But first let's answer your question about what to get for off-road use. Of the three vehicles you have chosen, I would lean towards the Toyota 4Runner first because it offers more upgrades such as suspension kits and bumpers. However the Xterra trucks have a growing group of followers and enthusiasts and since they could be had with a locking rear differential, I would have absolutely no problem recommending one of them as well. The Jeep Liberty is a hard one. I am not as big a fan of the Liberty unless it's a diesel. I really really like the diesel Libertys and if you could find one, not only could you build it into an OK off-roader, but you could also get some great mileage out of the diesel. Another one that I would recommend is an '04-'06 Jeep Wrangler TJ Unlimited, especially if you can afford one with the Rubicon package. The TJ Unlimited Rubicon is an awesome out-of-the-box truck ready to wheel. I like the 104-inch wheelbase for a comfortable ride and hillclimb ability, plus the longer wheelbase offers more interior room, the 4.0 engine is as reliable as anything, and the Rubicon package is hard to beat off road since it has front and rear locking differentials and lower gearing in the transfer case...all things you want for off-road use. And being a Jeep Wrangler you can take the top off for great visibility off road and excellent summer driving unlike the other trucks your mentioned. Unfortunately, I think you'll have a hard time finding a Rubicon Unlimited in your price range, but a basic Unlimited Wrangler without all the lockers would be a great Jeep to start with and you could install gears and lockers down the road as time permits. Plus since the Wrangler Unlimited TJ was only built for three years I would think it will hold its value.

Now about people giving you a hard time for being Asian, I really think that's lame. I'm a white country boy, and I love this country, and I must admit that I get a little frustrated when people aren't willing to speak English while in this country, but that's mostly because I like to communicate and it makes it more difficult. I also realize that this country is so great because it's made up of people from all different races, religions, and ethnic backgrounds. I think it's dumb when people want to fight over race or stuff like being into different types of cars or trucks. Hey, I'm a car guy. I don't drive an import tuner, but I think it's great that guys are into it even if it's not my thing. I don't understand why people would be upset about you driving a 4x4 or being on a trail if you're not a white guy? It seems to me that they are just being childish.

From reading your letter you seem smart, accomplished, and interested in the sport of four-wheeling, and as such you're much further ahead of the goons giving you a hard time about being Asian. I must admit that four-wheelers often give each other a good ribbing every now and then and as such it's always good to have a relatively thick skin. But at the same time just explain to them that you're there to run the trails and play with your truck and if they continue to hassle you just try to ignore them, or get your friends together and go find a different trail. With the latest technology the world is quickly becoming a smaller and smaller place, and as such it means people need to learn to get along. I know there is a fine line between standing up for yourself and turning and walking away from the situation. I have found that sometimes when someone feels they are being tough and giving me a hard time that it works best to flat out ask them what they are trying to do. It's amazing how it confuses the bully.

I hope that helps and I hope that a few bad apples don't turn you away from this sport. I'm going to make your letter the Tech Letter of the Month though it's more of the moral letter of the month. I think it's a good thing to discuss. Our trails are constantly being closed down, and having more people out there enjoying them together and respectful of each other is important to keeping them open. In-fighting amongst our ranks is a surefire way to help the anti-off-roaders win. I'd like to send you one of the new ARB snatch straps. ARB ( offers a full line of recovery gear in addition to its many bumpers, off-road lights, suspensions, and locking differentials (all items you might want to look into for your new 4x4). The snatch strap I'll be sending you is part of ARB's new line of gear with different colors to coordinate tree protectors, snatch straps, and winch-cable extension straps. The snatch strap ARB will be supplying is rated at 24,000 pounds and has some great features such as reinforced seam sleaves and redesigned eyes for ease of attachment, plus there is an internal bright red safety flag that is revealed over time as the strap wears to let you know when it's time to be replaced.

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