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Techline: Your Top 4x4 And Off-Road Tech Questions Answered Here

Posted in How To: Tech Qa on August 2, 2018
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Bump Out

I have a ’18 Ford F-350 diesel with a 2-inch front coil lift. It has Fox 2.0 shocks. The suspension company supplied bumpstop blocks. I’m confused as to why a modest 2-inch lift with all coil and no coil spacers would even need bumpstop blocks. My wrench dutifully installed them, and they are getting kissed every day in normal driving. Do I need them or can I yank them?
Reno Ceferino Lamb
Via facebook.com/JohnCappa4x4

Bumpstops are an important and integral part of the suspension on a 4x4. Modifying or removing them without proper testing, inspection, and suspension cycling can cause tire damage and potentially allow steering, suspension, and drivetrain components to collide, which can lead to an expensive repair bill. Suspension companies typically supply extended bumpstops with a lift kit for several reasons. Generally, a lift kit is designed to fit a specific tire size. In this case, the bumpstop spacers are included to keep the tires out of the fenders when the suspension is fully compressed. Keep in mind that the tires will stuff farther into the fenders during articulation off-road than they will under normal street use when the suspension bottoms out, such as when hitting a dip at speed. In other cases, the extended bumpstops are utilized to keep the longer aftermarket shocks from fully compressing. Typically, a 2-inch lift will use the stock-length shocks in most applications. If this is the case, the spacers would not be needed for anything more than to keep the tires out of the fenders. However, if longer-than-stock shocks are utilized to increase suspension droop (downtravel), bumpstop spacers will likely be needed to preserve the shocks and shock mounts. If you remove the bumpstop spacers, you could bottom out the shock bodies, which could destroy the shock seals or other internals. Continued shock bottoming can cause the shock mounts to tear off of the axle or frame as well.

Before removing the bumpstop extensions, inspect the shock shafts to see how much of the shock travel is being used during compression when the bumpstops make contact. There should be a dust or light oil ring around the shock shaft. This is a good telltale sign of how far the shock compresses. You can measure the length of the dirty shock shaft and compare it to the height of the bumpstop extensions. If it looks as though there is plenty of shock shaft showing when the bumpstop makes contact, you might be able to remove the extensions.

You can also figure out how much shock shaft is being used with a few plastic zip ties. Install a zip tie around each shock shaft and push it toward the shock body near the seal. Take the truck for a spin where you think it’s bottoming out and then inspect the location of the zip tie on each shock shaft. As the suspension compresses, the zip tie will be pushed along the shock shaft by the shock body. If there is enough shock shaft available to remove the bumpstop extensions, you should be good to go. If a zip tie gets crushed or is missing after your testdrive, the shocks are likely bottoming and you’ll need longer bumpstops. In most cases, you don’t want the shocks to fully compress before the bumpstops make contact.

JK Dilemma

I’m looking at a ’08 Jeep JK Wrangler Unlimited with 100,000 miles on it. It has a salvage title and is selling for $11,000. If I go this route, I intend to swap in an LQ4 GM V-8 and a 4L60E automatic transmission. I’d likely upgrade the axleshafts and make it a mild, daily driver-ish weekend trail cruiser. The other option would be to finance $30,000-$35,000 and buy a nice newer JK Unlimited Rubicon. I’m torn, so which route would you take?
Sean Yeo
Via facebook.com/JohnCappa4x4

Choosing one particular 4x4 over another is never an easy task, and it’s certainly up for argument based on personal preference. Power output appears to be at least somewhat important to you. Given that you would swap the anemic 3.8L V-6 out of the ’08 JK Wrangler, I assume you would prefer to have the 3.6L V-6 found in the ’12-and-up JK. The 85 more horsepower makes an engine swap less necessary. Unfortunately, I’m not a big fan of either of your choices here. I’d have a really hard time choosing the JK over the ’18 JL. The cost of the salvaged ’11 JK along with all of the modifications you have planned will put you well into a significant down payment on a new JL, if not pay it off completely. The JL really is a much better Wrangler. The 3.6L V-6 coupled with eight-speed automatic transmission is a real game changer. You should be able to easily retain the stock axle gears with up to 35-inch tires. The 3.6L and eight-speed automatic is just a much better combination than any engine and transmission combination ever available in the JK from the factory. If you want the lockers and other Rubicon accouterments, you can get into a new base-model ’18 JL Unlimited Rubicon for around $41,000. Of course this is about $6,000 more than you wanted to spend on a newer JK, but what if you could get into a lightly used JL Unlimited Rubicon? That should put you very close to the $35,000 max that you wanted to spend. So my advice would be to keep an eye out for a used ’18 Jeep JL Unlimited Rubicon. You’ll end up with a much better and more powerful drivetrain combination, plus you’ll get all of the improvements that the ’18 JL has over the JK.

Rover Hemi Swap

I hope that you can help point me in the right direction. I am swapping a 6.4L Hemi into a Range Rover Classic and I’m struggling to find a wiring diagram of any sort. There isn't much aftermarket support here in Australia for the third-generation Hemi V-8.
Adrian Connor
Via facebook.com/JohnCappa4x4

Unfortunately, I don't know of any easy-to-follow wiring diagrams that could help you with your swap. However, there are several companies that specialize in Hemi V-8 swaps that offer stand-alone plug-and-play wiring harnesses and computers. Companies such as Hotwire Auto (hotwireauto.com), Red Rock Offroad and Performance (redrockwiring.com), and TeraFlex (teraflex.com) offer the wiring harnesses and computers you need to get your project running right.

F-150 Joint Eater

I have a ’03 Ford F-150 that I wheel and love. It has 3-inch-lift spindles and 2-inch-lift coils. This combo eats through the upper and lower ball joints at a fast rate. I’m tired of replacing them every other month. Are there high-angle ball joints I could swap in or does anyone offer affordable high-angle upper and lower control arms? I wanted to install a long-travel suspension kit but I’m a broke college kid that can’t afford that right now. Thanks for any info you have.
Wesley Richards
Via facebook.com/JohnCappa4x4

The ball joints on an A-arm suspension should last quite a bit longer than two months, even on lifted applications. Stacking lift kits is usually not recommended because problems like this can arise. However, in your case, the lift spindles should not alter the geometry of the ball joints, which leads me to believe that the problem is with the lift coils, bumpstop locations, or you have excessively large or wide tires and wheels with very little wheel backspacing.

I suspect that the premature wear is being caused by the ball joints binding or you are using low-quality parts. Have you tried high-quality Moog (moogparts.com) replacement parts? If you have modified the factory bumpstops for more wheel travel or any of the bumpstops are bent or missing, the ball joints may be binding at full suspension compression or droop. Longer-than-stock shocks could also be the culprit in letting the suspension cycle past the available angularity of the ball joints. An upper high-angle arm is usually required for proper suspension cycling in an application such as yours. Companies such as Camburg Engineering (camburg.com), Tuff Country E-Z Ride Suspension (tuffcountry.com), and others offer upper control arms with high-angle joints. New lower control arms with high-angle joints are generally not needed until you install a long-travel suspension kit.

Divorced Drive

I need an intermediate shaft between my transmission and divorced NP200, right? I just pulled the 351M out of my Kaiser M725 to make room for the 454, and whoever hacked that Ford stuff in there U-jointed the slip-yoke right to the NP200 input.
John Crandall
Via facebook.com/JohnCappa4x4

Working with a divorced transfer case introduces a few problems that are not an issue with a married transfer case. Just like with the driveshafts between the transfer case and axles of a traditional 4x4, the U-joint angles of the driveshaft between the transmission and transfer case need to be spot on or there will be significant driveline vibration. Many people have fabricated transmission and transfer case mounts that only utilize one U-joint between the transmission and divorced transfer case. I’ve even seen no slip joint at all with a single U-joint bolted to the two yokes. There are some right and wrong ways to do this if longevity is a concern. To make a single U-joint work successfully and reliably in this application, the transmission output shaft and the divorced transfer case input need to be lined up perfectly. Any misalignment will cause premature wear of the transmission output bearing, slip joint, U-joint, and transfer case input bearing. This is incredibly difficult to do in the tight confines under a 4x4. It would seem simple enough in a controlled environment, but the transmission and transfer case are constantly moving because they are attached to the flexible frame of a 4x4 on rubber or urethane mounts. The only real way to keep them from moving independently is to fabricate brackets that physically attach the two components. You’ll likely be better off fitting a driveshaft with two U-joints between your transmission and divorced transfer case. Ultimately, a proper traditional driveshaft in a divorced application will give you more flexibility for mounting methods and location of the engine, transmission, and transfer case.

Special Steering

I have a ’07 Chevy Silverado with a Fabtech 6-inch lift. I bought the truck in 2009 with the lift already installed. I recently rebuilt the frontend including upper and lower ball joints, control arms, and tie rods. The truck had different outer tie rods from Fabtech due to the lift. When I took off the outer tie rods I noticed that the inners had been cut. I downloaded the instructions for the lift and did not see anywhere in the instructions to cut them. I don’t have the greatest turning radius and I’m thinking that’s why. Would you have any idea why someone cut the inner tie rods and would that affect the turning radius? They seem to have around 1.5 inches cut off of the threads. The truck drives great and I’ve put over 130,000 miles on it since I’ve owned it. The truck was brought in from out of state and I don’t know who did the lift to ask them. Thanks in advance for any information and help on this.
Andy Troisi
Via email

The Fabtech (fabtechmotorsports.com) 6-inch lift kit for many GM trucks requires the installation of shorter Fabtech tie-rod ends. These ends are necessary to accommodate the replacement spindles. I can’t imagine why the tie rods were trimmed, although it’s possible that the previous owner may have at some point tried to replace a worn set of shorter Fabtech tie-rod ends with longer stock parts, which of course would not work. The cut-down tie rods shouldn’t be an issue as long as you still have plenty of thread engagement and enough adjustability to set the toe-in properly.

As for the reduced turning circle, this can be attributed to many different things on a lifted truck including the lift kit design, tire and wheel selection, scrub radius, and so on. Rest assured that the cut tie-rod ends will have nothing to do with the decreased turning circle unless the truck cannot be properly aligned. If the truck has the proper toe-in setting, you should be good to go.

4x4 Van Life

I have been wheeling all my life, even since before I had a driver’s license. I need some help. I recently picked up a ’79 Dodge van with a Pathfinder 4x4 conversion. I would love any information or some place to get help with my van. The best part is that the van has a propane conversion. It will run on both gas and propane.
Rich ’N PJ Maughan
Via facebook.com/fourwheelermag

Most 4x4 van conversions made use of existing 4x4 drivetrain and suspension parts, which were readily available. I suspect what you will find is that the front axle is a Dana 44 or Dana 60 from a Dodge truck of that same era. A quick look at the axlehousing, wheel lug bolt pattern, and the brakes should help identify the axle. The transfer case, regardless of if it is married or divorced, is likely an NP205 if the 4x4 conversion was performed in the late ’70s or early ’80s. Replacement parts for the front axle and transfer case are still readily available. Aside from the 4x4 system and the propane conversion, your van should use all the same parts as a two-wheel-drive van and should be easy to work on. Late-’70s vans are not all that complicated. If you have trouble doing the work yourself, there are several 4x4 van conversion companies still around today that can help you. Both U-Joint Off Road (ujointoffroad.com) and Quigley (quigley4x4.com) specialize in 4x4 van conversions and should be able to help you with any repairs or modifications you want to make.

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