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Techline: Answers to all your 4x4 tech questions

Posted in How To: Tech Qa on December 16, 2016
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Offset 60

I have J-truck question for you. I found a rough J3000 with 6-lug axles. I searched the web but found conflicting information. What years had the desirable offset Dana 60 rear axle? It was a semi-float, correct? Will standard Dana 60 gearsets fit? Would it be worth swapping into a lightweight wheeler? I want to eventually put lower axle gears in my Suzuki Samurai. I’m just brainstorming on the cheapest way to keep it 6-lug and get 6.16 or 7.17 axle gears.
@Josh Beall

It’s an uncommon J-truck, but not the one you are looking for. If they are the factory axles, it should have an undesirable closed-knuckle Dana 44 up front with drum brakes. Out back is likely a Dana 60, although a book I have says it could be a Dana 53. Regardless, based on the images you sent, these axles have the traditional 6-on-5.5 lug pattern. Unfortunately, the ’60s Dana 60 axles are questionable for heavy off-roading. I suspect this axle has undesirable 16 or 30 spline axleshafts, not the 35 spline shafts you should look for. Also, the rear axle in this truck is centered because this truck would have a Dana 20 transfer case in it. The axle is pretty much unusable for you anyway. Your Samurai will require a rear axle with the differential offset to the passenger side if you are retaining the factory Suzuki transfer case.

The early ’70s J2000s were available with a somewhat rare and desirable slightly offset 35-spline semi-float Dana 60. This is the J-truck axle you are probably looking for. Unfortunately, they came with a 5-on-5.5 lug pattern, not the 6-lug pattern you need to match your Samurai. You can’t simply redrill the lug pattern in the ’shafts because several holes will overlap. However, it’s not a totally insurmountable problem. You could order new axleshafts with the 6-lug pattern from companies like Currie Enterprises ( and Moser Engineering ( A less expensive option is to go with wheel spacer/adapters. A-Dapt-It ( offers conversion wheel adapters that go from 5-on-5.5 to 6-on-5.5 underPN 55506550.

The newer 6-lug 1/2-ton FSJ axles didn't come out until 1974, and by then, the offset semi-float Dana 60 was discontinued. A full-float Dana 60 was used in the later 3/4-ton J-trucks, but it features an 8-lug wheel pattern, and it has a centered differential. Again, this is not something you can use on a Samurai with a transfer case that has an offset rear output.

All of these J-truck Dana 60 rear axles utilize a traditional Dana 60 ring-and-pinion. There are lots of gear ratios available for this axle. They range from 3.31:1 to 7.17:1. The carrier break is 4.56:1 and up.

If a Dana 44 and 5.89 gears are enough axle for your application, you could consider a ’74-’79 Quadra-Trac Wagoneer rear axle. This axle has the differential offset to the passenger side just like the Suzuki Samurai; will be around 60 inches wide; and comes with the 6-lug wheel bolt pattern you need. It is also much more plentiful than the semi-floating J-truck Dana 60 axle.

8-Lug F-Series

I have a ’78 Ford F-250 with Dana 60 axles front and rear. It came with 1/2-inch wheel studs from the factory. I am running 37-inch tires. Are the studs my weak link? Is it worth changing over to 9/16-inch studs?
Via Instagram @cappaworks

For whatever reason, the early Ford 3/4-ton trucks came with 1/2-inch wheel studs. Other 3/4-ton trucks of the same era typically have larger 9/16-inch wheel studs. It shouldn’t be a concern, even with 37-inch tires. You have eight of them on each wheel. Just make sure they are long enough to work with your wheels of choice. Sometimes longer wheel studs are needed on older trucks that originally came with steel wheels. Aluminum wheels have a thicker mating surface than steel wheels. Torque your 1/2-inch lug nuts to 100 lb-ft. Once they are tight, you should have at least three threads poking through on a traditional acorn-style lug nut.

80-Series Rocker Protection

I have a Toyota 80-series Land Cruiser. It’s not lifted, but I take it off-road regularly. I don’t go on really hard rockcrawling trails. It mostly sees mild adventures with a few boulders and washouts. I recently damaged the factory passenger side step by sliding it over a rock. I’d like to keep the original steps and reinforce them so they don’t get destroyed when I slide over an obstacle. What is the best way to do this? Can I use tubing and attach it to the body and frame? Will I need reinforcement plates on the frame for the legs of my home-built rock sliders?
@Ted Olmstead
Crest, CA

Rockers guards are usually the first modification I recommend for people that plan to take their 4x4s off-road. It doesn’t take much of a mistake to quickly do a lot of damage in the rocker area. Unfortunately, the factory plastic steps on the ’98-’07 80-series Toyota Land Cruisers are not very durable. They also hang down pretty far and suck up valuable off-road ground clearance. If you wanted to replace them with something more durable, Slee Off-Road ( offers both Tube Sliders and SliderSteps. The SliderSteps provide a solid flat surface to help with entering and exiting the vehicle. Both the SliderSteps and Tube Sliders attach to the frame via three legs with heavy-duty 7/16-inch U-bolts. No welding is required for installation. The company also offers the bolt-on SliderSteps for the Lexus LX470, which is essentially the upfitted twin to the 80-series Land Cruiser.

Now, if you wish to retain the original plastic steps and you are a handy fabricator, it should be possible to build an underframe using square or round tubing, or a combination of tubing types. Avoid attaching your slider structure to the frame and body. These two components move independently of each other. Connecting them will lead to body and step damage. I think you will be better off attaching your home-built sliders directly to the outside of the frame. You can bolt them in place with a large foot, use U-bolts similar to the Slee design, or you can weld them directly to the frame. I would recommend at least three legs per side made from something like 1.75-inch, 0.120-wall DOM tubing. If you decide to weld the sliders to the frame, you’ll likely want to weld 3/16-inch-thick reinforcement plates to the sides of the frame where the rocker legs attach. The legs can then be welded to these plates. It will help stiffen the assembly and keep the legs from cracking off of the frame. You may also want to add gussets where the legs meet the frame for additional reinforcement. Try to stuff a fairly robust material under the steps, again something like 1.75-inch, 0.120-wall DOM tubing would be ideal. You could then use 1.25-inch, 0.120-wall DOM for the rest of the structure. You may be able to gut the underside of the step for extra clearance. The step should just sit on top of your rocker structure. Give yourself at least 1/4- to 3/8-inch clearance between the two.

Toyota 22R Repower

I have a ’85 Toyota pickup with a carbureted 22R engine. I’ve put about 15,000 miles on the engine since a rebuild. It has a stock bore, 261 cam, headers, intake, Weber carb, and an MSD ignition. It's on 35-inch tires with 5.29 axle gears. I daily drive it, and I live at 9,000 feet above sea level. The intake and Weber carb have to go for a propane conversion. I've already got an EFI intake that I would use for the conversion if I went that route. I currently don't drive the truck off the mountain due to it being jetted for up here, and it will run too lean off the mountain. In your opinion, would it be better (cost effectiveness, performance, and so on), to just keep on driving it with the current setup and save for a motor swap to an RZ or a GM 4.3L or something of that sort, or to just go propane and purchase enough tanks that I can still daily drive it? The end goal is to be able to drive it at any elevation and not have to re-jet anymore.

Also, an RE conversion is out of the question. I'm not into 30-year-old injection systems. I currently have another vehicle to drive to lower elevations.
Via Instagram @cappaworks

I’ve never really been a big fan of propane power for a daily driver or even a trail rig. It can be difficult to find fuel in some areas, especially at odd hours. Transporting extra fuel for long trips off-road also poses a problem. Engine swaps typically open a Pandora’s Box of issues that need to be solved. This includes things like a transmission swap, motor mounts, driveshafts, cooling, exhaust, wiring, and more. The cost of an engine swap would be prohibitive for your situation. It doesn’t sound like you really want more power, you simply want a powerplant that’s more street-friendly at all elevations. For all these reasons, I’d recommend that you retain the Toyota four-cylinder engine and go with a factory fuel injection conversion, despite your aversion to it. Off Road Solutions ( offers an EFI conversion wiring harness for your application. It utilizes the factory Toyota fuel injection components, which could be sourced from a parts truck or at a wrecking yard. The fuel injection will provide more reliable and consistent performance at all elevations than the carburetor. It will be a much easier swap than an entire engine conversion, and as an added bonus, the EFI will perform better than your carb at the odd angles frequently encountered off-road.

Selectable Locker Lowdown

What's more reliable, an air locker or an electric locker?
Via Instagram @cappaworks

There are several different selectable lockers available today. Some are engaged by air pressure, some electricity, and others by a cable. The engagement reliability is typically more dependent on the quality and meticulousness of the installation than the actual unit itself. Careless routing of air lines or wires can result in both being damaged by heat or chafing. Difficulty in repairing an air line versus a wire is pretty much a wash, as long as you have the correct parts and tools for the job. If you have an ARB ( Air Locker for example, the company offers a convenient and handy air line repair kit under PN ASK001. It includes nearly 7 feet of replacement air line, two splice connectors, and various other handy air line plumbing pieces.

Electrical engagement has the advantage of being a much more simple system. It requires fewer components with the potential to fail. An electric locker utilizes a 12V power wire, a ground wire, and a switch in the dash. An air-actuated locker requires some sort of compressor, which will require a wiring harness and switch, hose, electric air solenoid, and related wiring to direct the air pressure to the locker. However, we have seen these systems simplified and the electric air solenoid replaced by the use of a manual pneumatic switch. These pneumatic switches and the plastic air lines are offered by companies like Mettle Air (

Both the electric lockers and air lockers are designed to function without issues for more than 100,000 miles if properly installed and used appropriately. However, the actuation mechanisms inside the lockers can also be put under some scrutiny. The air seals inside of an air-actuated locker can be damaged if the oil becomes contaminated with dirt or metal chips. Likewise, larger metal bits from broken components can cause havoc in any electric locker that utilizes an electromagnet for engagement. It should go without saying, but you’ll basically want to keep the differential oil clean regardless of if you have an air-actuated or electric-actuated locker.

Now, if you want to talk pure brute strength, the ARB Air Locker is likely the strongest locker offered today. That’s not to say the others are weak, but some other lockers can succumb to collateral damage and fail when an axleshaft breaks.


What is the shortest drivetrain (engine, auto tranny, and transfer case) combo you could put together that would push 37-inch tires at highway speeds but still be geared low enough to crawl? I'm thinking a lightweight vehicle like a Suzuki Samurai, but it would also apply to a CJ-5 or similar.
Via Instagram @cappaworks

I love hypothetical questions like this, but the answers are usually pretty ridiculous and not very practical or inexpensive. So the shortest possible and still useable combo would likely be a Mazda 13B Rotary engine mated to a Ford C4 automatic or a Powerglide if you can get by with only two transmission speeds. You have more choices when it comes to transfer cases. Options include the ’80 Jeep CJ version of the Dana 300 or an NP231 with a Novak ( Ultra-Short Shaft slip-yoke eliminator kit. There are also some heavy-duty compact aftermarket transfer cases available such as the Advance Adapters ( Atlas with the optional short 32-spline tailhousing, Red Winches ( Griffin, and the Trail Worthy Fab ( Hero Two Speed and Three Speed transfer cases.

The Mazda Rotary engine has a different power curve and an rpm redline that’s nearly double what you’ll find in traditional four-, six-, and eight-cylinder engines. For this to all work, you’ll need to be running some seriously deep gears in the axles. You’ll likely want your ring-and-pinion to be in the 6.00:1 to 7.00:1 ratio range.

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