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May 2008 4x4 Tech Questions - Nuts & Bolts

Posted in How To on May 1, 2008
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Confused? E-mail your questions about trucks, 4x4s, 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.

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


Question: I have a military 1 1/4-ton Chevy pickup, sporting a 6.2L rattler and backed by a 400 turbo. I want a beefy automatic with overdrive but I am not sure what options are available. I know the ol' 700R4 would work with the correct converter, but I am looking to explore the 4L60 and 4L80 candidates. Will they work and how do I go about getting one to work with my non-ECM-controlled truck? I surmise I'll need an adapter from the trans to my original transfer case. I contacted Advance Adapters and they gave me generalities, but couldn't give me an answer on which one would work. I have no problem with changing the crossmember and driveshafts. I would like to slow the rpm down a little so I can achieve 65 mph without having the motor scream. I do want to keep the 4.56 gears, so I think the best option is the overdrive.

Answer: What you want is a 4L80E, the electronic overdrive automatic with strength comparable to the TH400. Advance Adapters (800.350.2223, sells these transmissions and can offer you a Compushift controller from HGM Electronics (877.744.3887, I have one in my Red Sled project truck and it works great, plus it has a stand-alone computer that only requires a throttle position sensor that can be added since your truck doesn't come with one. Tell them you want the torque converter built for a diesel and that you have an NP208 transfer case with a 32-spline input and they will take care of the rest.

Question: I like listening to music when I go wheeling, but half the time I can't get good reception out in the hills. Plus my CDs get all scratched up when I bounce around. Do you have any ideas for better radio reception?
Chett B.

Answer: Though I rarely listen to music when I'm wheeling, I do travel a lot and have found that satellite radio is where it's at. I have a Sirius satellite receiver ( that I can put in any vehicle I drive as long as it has a normal radio, and it picks up the broadcast of the same channels over the whole nation and way out in the boonies. I usually hit channel 28 Faction for my current rock music, Channel 14 Classic Vinyl for my classic rock fix, Channel 63 Outlaw Country for my country tunes, and channel 103 for Blue Collar Comedy. It's not cheap, about $12 per month, but if you're a fan of music, this is the way to go for back-hill travel. Of course do your fellow wheelers a favor and keep the volume to a level that only you and your passengers can hear, cause though I like just about any type of music, I'd rather listen to engines revving than somebody else's favorite song when in the dirt.

Question: I am doing an 8.1L GM big-block swap and read the articles on Project Excursion Killer (May, June, and July '02) and you said you used a "trick new EFI controller." Could you tell me what brand or where to get this?
Chris V

Answer: The Excursion Killer had a controller from Technical Services (574.457.4004,

Question: I'm a second-year college student on a general education program and want to transfer and get my degree in mechanical engineering. I want to apply that degree towards something in the truck/4x4/off-road industry but don't know where to start. I was hoping one day to do R&D for a suspension lift company or something like that, but I am completely lost on how to go about even finding out what kind of training and education is needed for that line of work. I've been reading for years and you guys seem to be the gurus on everything off-road, so I figured you might be able to help a little bit. How do I go about putting me to work in the off-road world?
Kelly Burkholder

Answer: First do some research. Call and talk to engineers at companies that make parts you like, find out how they got there, what they studied, what their background is. Maybe it's your favorite suspension, favorite truck, or favorite widget. Also talk to the company owners or human resources person and ask what they are looking for. And start with part-time jobs or internships at local 4x4 manufacturers, suppliers, or shops to gain practical experience.

Question: I have a Jeep Wrangler, and after reading about your Ultimate Adventure Rubi Wagon Jeep buildup with the Cummins diesel swapped in, I really want to put a diesel in my Jeep. However, since the Cummins is so darn big and heavy, are there any smaller versions available that will give me diesel mileage and torque?
Jim P.

Answer: I understand your dilemma. There are a bunch of great diesels available, but most are heavy as anchors and demand tons of work to stuff in a Jeep. Even the elusive four-cylinder Cummins weighs more than a big-block gas engine and will require a complete drivetrain swap to survive in a 1/4-ton Wrangler. I've seen some awesome smaller diesels in the works for future 1/2-ton trucks (such as the new Dodge Ram 1/2-ton), and great little foreign diesels, but those are all still out of reach due to time, space, and importing regulations. However there may be another option on the horizon. I recently got this photo from a super-secret OEM performance research facility where we see a Jeep chassis from a long-wheelbase military TJ Wrangler with a 2.8L, four-cylinder VM Motori turbo-diesel engine that my research found produces 158 hp and 295 lb-ft of torque. This is nearly identical to the diesel as found in the diesel Liberty, which I felt was a great running powerplant, but if it's military I doubt it's as complicated as the KJ Liberty version. Now this might not sound like much, but when stuffed in a Wrangler I bet it's a hoot to drive and it should work with some of the factory transmissions, at least the later manual transmissions. Hmm, why would a performance accessory division of an OEM be messing around with a diesel engine and why would there be a Rubicon TJ there as well with the hood up? I couldn't get a straight answer when I started asking the hard questions to the marketing reps, but when I learn more I'll let you know.

Next start looking at trucks and 4x4 parts and try to figure out why they are built the way they are built. Ask questions. Whether it's the guys who sell the parts, install the parts, or design and engineer the parts, they can all give you insight on why stuff does or doesn't work. And at the same time, don't stick to the 4x4 world only. Look outside the industry at other neat products-maybe a tractor has a strong axle, or a lawn chair has a comfortable shape, or a tow truck has a special winch-any and all of these will spur on ideas that can someday be applied to an engineering position. I would recommend taking some business classes along with your engineering. It will be very valuable to know how to make a product work, make it within a budget, and sell it. Even if you are never in sales it's good to understand the big picture when working for a business.

Question: I have a '94 4Runner and plan on installing a Marlin or all-Pro solidaxle swap. i see articles about people using '85 Toyota front axles. Will a '69-'89 Land Cruiser front axle work? I would assume the 9.5 front end would be stronger, allowing me to run 37-inch or bigger tires without any mods to the axle. Can you shed some light on this matter?
Jeff s.

Answer: I contacted the folks at all Pro Off Road (951.658.7077, www.allprooffroad. com)and we discussed your idea of using a Land Cruiser axle. They recommended using a mini-truck axle first because of the stronger selectable hubs and the wider variety and lower cost of aftermarket support for everything from gears and bearings to trusses and housings, and because the leaf springs are already on top of the axle whereas the Land Cruiser axles were spring-under from the factory. also the FJ-80 high-pinion drop-out centersection is stronger than the earlier Cruiser low-pinion even though it is only 8-inch versus 91/2, and it can be fitted into the mini-truck housing and will help with driveshaft issues when used in a v-6-equipped 4Runner. if you do decide on the Land Cruiser axle, we recommend a '79-or-newer version since it has knuckles that accept high-steer arms. Make sure you get the fine-spline pinion variant. However, the first choice would be a built mini-truck axle or aftermarket housing with mini-truck internals.

Question: I am building up my first off-road rig. i am 17 and have an '87 Jeep Cherokee with a 4.0L Fi, five-speed manual, an NP231, a Dana 30 front, and a Dana 35 rear. i was planning on getting a Rough Country 6.5-inch X-Series lift and 33-inch tires, but i wanted to get some more advice from experienced wheelers. Will my axles hold up with 33-inch tires during moderate wheeling? Should I forget about that lift and save for some Dana 60s or big axles and then later go for a custom lift? i don't have a lot of money but am willing to take a lifetime to build this rig properly and safely, because it will be my daily vehicle.

If I did get that lift could i install it with the help of my friends? if i paid someone to do it (4x4 shop) i wouldn't learn anything, but i want to be safe and be able to drive it and not worry about my tire falling off. What would you recommend? Will my 4.0 push my Jeep with 33s, bumpers, and a full exocage? i love fixing stuff, especially engines and vehicles. i know anybody can do this stuff if they take their time and get advice and know-how from experienced people. But safety is key and i don't want to bust up trails because my rig was built wrong.
Josh R.

Answer: Your '87 Cherokee is exceptional off road and has tons of accessories available, and you should have no problem installing the Rough Country suspension. Take your time and follow the instructions. your axles will be fine with 33-inch tires for moderate use so don't sweat it. it is easy to wait and wait until you have money for big axles, but you might as well build the truck with what you have and just start wheeling. When you break you will learn what needs to be upgraded. The 4.0L will handle the addition of bumpers and an exo, but remember by adding extra weight you are adding stress onto the lightweight axles.

I'm encouraged that you are looking for advice and so we want to give you this month's Nuts i'm Confused letter award. This month i have an ECTED for your Jeep project. ECTED stands for Electronically Controlled Traction Enhancing Differential. it provides the user with a selectable limited slip or locker mode. When selected "off," the ECTED functions as a performance limited-slip differential for on- and off-road excitement. When selected "on," the ECTED becomes a locker or spool, which is ideal for the nastiest off-road terrain.

Auburn Gear (260.925.3200, www. has the following units available: aMC 20, Dana model 30, 35, 44, and 50 for front axles, Ford 8.8, GM 8.5 10-bolt, and GM 87/8 12-bolt. Thus you could get the locker for your current Dana 35, or learn to wheel with an open diff and get a Dana 44 or Ford 8.8 model for a future rear axle upgrade.

Question: I am not an engineer of any sort, but I have recently been working on two new tire designs that I feel would benefit the current pneumatic tire industry. One concept is geared for passenger vehicles of all shapes and sizes and would, in theory, grant greater traction, stability, longer tread life, and twice the safety of current conventional tires. The second idea is a wheel system designed for heavy industrial and military applications as it would provide the strength and durability of solid rubber tires while retaining the comfortable ride of pneumatic tires. Not to mention this wheel would be literally bulletproof. I have produced technical illustrations of these two tire concepts and have copyrighted my work (via a "common law copyright"). Unfortunately I have tried numerous times to contact virtually every tire manufacturer in the U.S., but none of them seem to have the desire to reply back to me. Any ideas on what I should do next to bring my inventions to life?
Matthew Todd

Answer: In these days of lawsuits galore and patent infringement, there are some thin-ice situations when discussing product ideas. Open discussions are one thing but when it gets to intellectual property, that's a whole new situation. A company has to be very careful about looking at designs outside the company as they don't want to open any doors that would allow for someone outside the company to allege that they "stole" intellectual property. Many engineers don't even want to see anything of this nature unless it has gone through the proper filters. Oftentimes corporations have a lot of active projects. There is a chance that something they are working on could be similar to what an outsider proposed, which can lead to litigation. There is no doubt that companies like Michelin, Goodyear, Firestone, and Toyo pay a lot of people a salary to generate ideas and concepts. You may be having trouble trying to sell your idea because the company is already working on lots of other ideas that have been reviewed. I would recommend your getting a patent lawyer to discuss your idea with first. From there you can shop it around to the head office and the technical center or research center or similar businesses if they exist.

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