Click for Coverage
Due to the EU’s Global Data Protection Regulation, our website is currently unavailable to visitors from most European countries. We apologize for this inconvenience and encourage you to visit for the latest on new cars, car reviews and news, concept cars and auto show coverage, awards and much more.MOTORTREND.COM
  • JP Magazine
  • Dirt Sports + Off-Road
  • 4-Wheel & Off-Road
  • Four Wheeler

January 2006 4x4 Tech Questions - Nuts & Bolts

Posted in How To on January 1, 2006
Share this

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. Always check state regulations before modifying a vehicle with pollution controls or one that will be driven on the street. We will answer as many letters as possible each month, but due to the large volume of mail we receive, we regret that we cannot reply to unpublished letters or return photos. 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.

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

E-mail to:

Detroit Locker (800.328.3850, has just released the only locking differential for the Ford 9 3/4-inch axle. In fact, it's the only aftermarket differential for this axle at all. The new carrier should be available for your '97-and-newer Ford F-150 or Expedition by the time you read this-so any of you who were thinking of swapping a Dana 60 or Ford 9-inch axle into your late-model truck can put those plans on hold. The 9 3/4-inch locker (model number 225C-194A, PN 72147), will retail for $645. Unfortunately there's not enough left of our Ford to install one and test it out.

Question: I have an '01 Ford Ranger with a 3.0L V-6 and I was wondering if I could put a V-8 in it. If I can, what kind of rear axle do I need to handle the new power? I want to put a five-speed in it at the same time. What kind would work? And what about the wiring? What kind of stuff would I need for that?
Mike Walker
Camp Pendleton, CA

Answer: Sure, you can put a V-8 in your Ranger. The most popular donor engine is the '87-'93 Mustang 5.0L that people typically bolt in with engine mounts, headers, and radiators from Advance Adapters (800.350.2223,, James Duff (360.683.2160,, or L&L Products (972.475.5202, Even though we've seen V-8 Rangers with the 7.5-inch rear axle your truck has, we'd rather see you swap in an 8.8-inch axle from a 4.0L Ranger for reliability. If you want a five-speed transmission, your best options are to either run the Mustang's T-5 transmission or swap the entire 5.0L engine, transmission, and transfer case out of a fullsize F-150 into your Ranger. If you go the Mustang route, Advance Adapters has two kits that allow you to adapt the T-5 transmission to your stock transfer-case kit (PN 50-1802 or PN 50-1803). As far as wiring goes, there are a number of aftermarket harnesses available from Painless Wiring (800.423.9696,, Ford Racing (586.468.1356,, and Windsor-Fox (760.946.FUEL, to make swapping in the Mustang engine easier. If you choose to use a 5.0L from a fullsize truck you're going to have to salvage the factory wiring harness from the donor vehicle and adapt it to work with your Ranger's wiring. In other words, you're on your own, and you better have factory wiring diagrams for both vehicles!

Question: I have a '71 El Camino that we installed the drivetrain from a '78 Blazer into. I'm running a 327 V-8, with double hump (turbo heads), a 750 Edelbrock carb, a factory cast high-rise intake, a geardriven cam, and Hooker headers. Tires are 38x12.50-15 Gumbo Monster Mudders. What axle gear ratio do you suggest running-4.56:1 or 4.88:1? I would like to have it run down the road with ease, but yet still have a little bark when I take off.
Bill Eggers

Answer: Based on how you've built this truck we can't imagine you're going to be driving on the highway that much with it. If it were our toy we'd go with the 4.88s. We don't think you'd notice the roughly 200-rpm difference the engine would see at 65 mph, but you'd feel the difference every time you accelerated from a standstill with the 4.88s. In case you want to play with other gear ratio possibilities you can find out what your theoretical engine speed at 65 mph would be with the following formula: [(65 mph x rear axle ratio x transmission overdrive ratio-if you have overdrive)/tire diameter] x 336

Question: I have an '85 F-250. The problem is the front leaf springs are straight instead of having an arch in them. Should I change these out for new ones because they are straight instead of arched like the back ones? My buddy says change them because they might be dangerous. What do you suggest?
Eric Tidwell
Cross City, FL

Answer: Based on your description we'd say the leaf springs are fine. They don't have much arch because that is the way Ford designed them. The idea was that the flat springs provide a better ride quality than a positively arched spring would at the same ride height.

Question: I have an '03 F-250 Super Duty with the 6.0L diesel hooked to the five-speed Torque Shift transmission. Thus far I have installed the leveling kit to raise the front end, installed a turbo timer, rear airbags, 35-inch tires, and a K&N air-intake system, along with an auxiliary bypass oil filter. My next project is to work on the exhaust system. But I am getting mixed signals as to whether I should get a turbo-back system or an after-cat system. I live in central Utah and have to retain the catalytic converter to be legal. A lot of the aftermarket systems eliminate the cat altogether, but I have found a few after-cat systems. No one I've talked to can give me a horsepower difference between the two types of systems. My local exhaust shop told me that if the cat has to be retained, the factory 3 1/2-inch downpipe is just as good as any aftermarket 3 1/2-inch downpipe with the factory cat. What's the deal?
John Andrews

Answer: Here's the deal: Catalytic converters are more restrictive than a section of straight pipe of the same diameter. Very few states emissions-test diesel vehicles on a yearly basis at this time, so some truck owners remove the factory catalytic converter to improve exhaust flow. It's illegal-but it happens. Diesel trucks used in competitions should remove the cat because the excessive fuel that gets pumped out the exhaust (that makes the black smoke) could cause it to plug up over time.

That said, we think you should keep your cat and add an after-cat exhaust system to your truck. It's up to you whether you replace the factory downpipe you have now with an aftermarket piece. They typically will flow more, but as your exhaust shop said, you probably won't feel the difference with the cat in place.

Question: I have a '90 Jeep Wrangler YJ with a four-cylinder engine and five-speed transmission. I want to run 33x10.50-15 tires with about a 4-inch suspension lift. What I would like to know is what axle gears and locker should I put in the factory axles to handle these tires for general wheeling and daily driving? Do you think I need hydraulic ram-assist steering?
Mike Garland
Conway, AR

Answer: A set of 4.88 gears and a rear Lock-Right (864.843.9231, would be just about perfect for your combination. It would give you a 2,300-rpm cruising speed at 55 mph in Fifth gear, a 50:1 crawl ratio, and enough grunt to cruise around town without killing the clutch. Plus you'd have the added traction of a rear locker-without a huge investment in a rear axle that you'll outgrow if and when you move up to 35-inch tires.

I have a '99 Jeep Cherokee. It has a 4-inch suspension lift and a small set of 30x9.50-15 Dueler AT Revo tires. I have run into a few problems with it when certain parts of the engine get wet when I'm out playing. I have lost two alternators (due to drowning) and one computer for my transmission. The alternators where lost in part due to their location at the bottom of the engine. The transmission computer was lost when the hood was covered by water. I know submerging the Jeep in water isn't good, but it does happen. What can be done to protect vital parts from too much water?
FC Marshall
Milesburg, PA

Answer: If you can't keep your Jeep out of the water, you're going to have to keep water out of your Jeep. First let's think about where the water is coming from. When you splash through a mud hole or water crossing the tires spray a huge amount of H2O (under high pressure) in every direction. Your engine's cooling fan and serpentine-belt system can also pull a ton of water into the engine compartment and throw it all over the place. You can't seal everything in a waterproof bag, but you can help direct and deflect some of the water away from the vital components. We'd try using large rubber mud flaps as shields that cover the space between the bottom of the radiator and your Jeep's oil pan. What you want to do is make it harder for water to come in, but still give it a way to drain out. Our other tactic would be to convert the Jeep to a set of electric cooling fans that you can turn off just before you enter the water.

Your alternator problem is common, but often it's the grit in the water that kills them-not just the moisture. Get in the habit of carrying a can of electrical parts cleaner (available at any auto parts store) and flushing your alternator out after every off-road trip to prevent damage. We'd also think about relocating the alternator to a higher place in the engine compartment. Unfortunately we know of no aftermarket kits to do this.

Question: Can you tell me what size wheels were used on the Ultimate K10 with the new 39x13.5R17 BFGoodrich Krawlers? What is your opinion on running Toyo 38x14.50R16 MTs on 16x8 Weld Racing Stone Crushers? I would be using them on the road as a daily driver along with mild off-road use.
Micah Kelly

Answer: We're running 17x8 1/2-inch-wide Hutchinson (609.394.1010, Rock Monster wheels with our BFGoodrich 39x13.50R17 Krawlers. Generally we'd recommend wheels that are within 4 inches of the tire's listed width on the sidewall. So if you have a 35x12.50-15, we'd run an 8- to 10-inch-wide wheel. Toyo (800.442.8696, recommends you run its 38x14.50R16 tire on a 10- to 12-inch-wide wheel-so it's hard for us to tell you any differently.

Question: I have a small problem. I own a '92 Toyota 4Runner with a 2-inch body lift, Rancho torsion bars with 33-inch Goodyear MT/Rs, 4.56 gears, a Lincoln-locked front, and a Power-Trac in the rear. My problem is I keep bending centerlinks. I have yet to find a vendor that sells a beefed-up link. And even though I have a friend that works at a Toyota parts counter, this is getting to be an expensive habit! Do you have any ideas on how to stop this? Or someone who can help me?
Clayton Campbell

Answer: We don't see many people bending the centerlinks on these 4x4s. It could be the fact that you've basically put a spool in your front axle and you're stressing the centerlink more than it can handle. But typically Toyotas of that generation have tie-rod and idler-arm failures long before the forged centerlink bends. The first thing we'd do is figure out whether the idler arm is still in good shape. If it's letting the centerlink lift and twist in some unusual way, it may be causing your problem. Total Chaos Fabrication (951.737.9682, manufactures a new super-strong idler arm.

If you continue to have this problem, look into having the stock centerlink sleeved with a piece of 0.120-wall DOM tubing. At that point you're also going to want to look into a ram-assist steering system, because right now the only thing protecting your steering box from busting is that bending centerlink.

Question: I'm 15 and will be getting my license soon (I hope). I love the whole sport from rockcrawling to desert racing to mud bogging. But what I'd like to know is what would be a good first 4x4? What should I look for? I don't have a large budget and I have to be able to drive it to school.
Ryan Durrant
Ontario, Canada

Answer: First of all make sure you get something that runs. Pick a mainstream 4x4 so repair and upgrade parts will be available at a fair price. Don't get too hung up on the perfect year, make, and model-because this won't be the last 4x4 you every buy. In most cases the ideal first 4x4 is a Jeep. That used to mean a CJ-5 or CJ-7, but now you might be better off with a Wrangler (YJ) or even a Cherokee (XJ) to avoid rust problems. If Jeeps are too pricey, you might also try a Ford Ranger, Chevy S-10, or even a Toyota pickup truck. As a general rule, small 4x4s always sell for less money than fullsize ones, and parts for American 4x4s will be cheaper than the same thing for a foreign truck. Also keep in mind that upgrades like off-road shocks, wheels, and tires cost the same regardless of what you're putting them on.

Question: I have an '03 Chevrolet Tahoe Z71 and use it for daily driving as well as semifrequent mudding and trail driving. The suspension is all stock, with a grilleguard and MileMarker 9,000-pound winch loaded on the front. Now that it has 30,000 miles on it, the front of the truck has lost a considerable amount of clearance and the suspension sags down significantly. I was wondering if there was any way to correct this without paying too much, as I am currently low on funds.
James McKee

Answer: First, make sure that nothing is bent or broken in your frontend and that both factory jounce bumpers (they're the orange foam bumpstops that contact the lower A-arms) are still intact. If everything looks OK, we'd take the Tahoe to an alignment shop to see if they can increase the torsion-bar preload to raise the frontend back up to stock specs. If they can't, you can order Off Road Unlimited's (818.563.DIRT) new 1/2-ton leveling kit (PN 6006-B2), which typically raises the front of a truck like yours 1 1/2 to 2 inches. Or you can order a set of heavy-duty replacement torsion bars from Sway-A-Way (818.700.9712,, which come with new torsion-bar keys to let you fine-tune your final ride height.

Connect With Us

Newsletter Sign Up

Subscribe to the Magazine

Browse Articles By Vehicle

See Results