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

Posted in How To: Tech Qa on July 7, 2017
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Ratio Right

I have a ring-and-pinion gearset for a Dana 44 from a ’70s Jeep FSJ. How can I tell if it’s a 3.73:1 or 3.07:1 ratio?

Harris Wells
Via email

Fullsize Jeeps were available with a variety of axle ratios throughout the years. These ratios varied from 3.07:1 all the way down to 5.89:1 depending on the year and model of the Jeep. Fortunately, there are several ways to tell what the ratio of an uninstalled ring-and-pinion gearset is. The easiest and most accurate method is to simply count the teeth on each gear and then divide the ring gear tooth count by the pinion gear tooth count. Let’s say you counted 43 teeth on the ring gear and 14 teeth on the pinion gear, 43 divided by 14 equals 3.0714. The number is then rounded to 3.07. So in this case, you would have a 3.07:1 ratio gearset.

Another method is to check the circumference of the outer edge of the ring gear. You’ll find many different numbers stamped into it. The numbers you are looking for will be something like 46/13, 43/14, 41/11, or something similar. The first number is the tooth count on the ring gear; the second number is the tooth count on the pinion. Just as before, you divide the ring gear tooth count by the pinion gear tooth count. A 46/13 is a 3.54:1 ratio, a 43/14 is a 3.07 ratio, and a 41/11 is a 3.73:1 ratio.

As an aside, it’s generally believed that lower ratio gears are weaker because of a decreased pinion tooth count and overall smaller pinion gear diameter. However, this is not always the case in every application. There are some low-ratio gears that have more pinion teeth than the next ratio up. Using the Dana 44 as an example, let’s take a look at the 4.89:1, 5.38:1, and the 5.89:1 ratios. The 4.89:1 ratio gear has 44 ring gear teeth and 9 pinion gear teeth, the 5.38:1 ratio gear has 43 ring gear teeth and 8 pinion teeth, and the 5.89:1 ratio gear has 53 ring gear teeth and 9 pinion teeth. It could very easily be argued that the 5.89:1 ratio Dana 44 gearset is every bit as durable as the 4.89:1 ratio gearset, and both could be considered stronger than the 5.38:1 ratio gear set.

Night Lighting

My wife and I own a ’15 GMC Sierra double cab. One big problem is the projection headlights. They are not bright enough and only project a short distance. Can you suggest affordable options? Should I change the bulbs or add a bull bar with aftermarket LED lights?

John Bednar
Via email

It’s not at all unusual for the factory headlights of a 4x4 to be inadequate on-road, and there is usually a lot of potential for lighting improvement off-road, especially at higher speeds. You have several options. Your truck utilizes a 9012-style headlight bulb. There are aftermarket bulb replacement upgrades available for this application. I would recommend trying the Sylvania Silverstar replacement bulbs (sylvania.com). They offer a brighter light that provides more clarity and reaches out farther into the darkness than the factory headlight bulbs. They simply plug into the existing wiring harness and headlight assembly. LED conversions are available for the 9012 bulb style, but some will require a wiring pigtail to be purchased as well. The 6,000-degree Kelvin light temperature created by many LED lights is preferred over other light temperatures. This is because the sun produces a similar light temperature. The human eyes see best and are less likely to fatigue in this type of light.

Add-on aftermarket lights are another option. However, many of these are not legal for street use. You’ll have to check with the manufacturers. If on-road use isn’t an issue, the sky is the limit. Many different companies such as Baja Designs (bajadesigns.com), KC HiLites (kchilites.com), and Rigid Industries (rigidindustries.com) offer many different sizes and shapes of aftermarket add-on lights that can be fitted to the front of your truck. For best all-around lighting performance you can add two flood beams for improved up-close lighting and two spot beams for long-range lighting. Some LED lightbars have both flood and spot beams built in so all of your lighting needs are covered in one unit.

Manual Shift 1356

I have a ’96 Ford Bronco. I am restoring the Bronco since it has 248,000 miles on it. I plan to rebuild or replace the transmission and transfer case. I don’t do heavy-duty off-road driving, but I do a combination of highway and off-road running. I would prefer the manual-shift over the electronic-shift transfer case. What is the best way to convert from electronic-shift to manual? Would I be better off getting a rebuilt manual-shift transfer case or can the electronic-shift transfer case be changed out to shift manually?

Al Biernesser
Covina, CA

It’s not uncommon or unfounded for people to distrust the electric-shift BorgWarner 1356 transfer case. Many of the early electric- and vacuum-shifted transfer cases are problematic, especially now that they have 20-plus years under their belts. Unfortunately, there isn’t a simple over-the-counter bolt-on manual-shift in-cab conversion for the BW1356. However, you can still occasionally find a Shiftster conversion on eBay (ebay.com). The Shiftster is a manually operated replacement for the electric transfer case shift motor found on the BW1356. It fits many different Ford 4x4s. The bummer is that it requires that you crawl under the vehicle to manually shift the transfer case each time. This could be problematic if you forget to shift into 4x4 prior to getting stuck door-deep in mud.

The other option is to completely replace your electric-shift BW1356 transfer case with a manually shifted version of the BW1356, which can be found in ’87-’96 fullsize Ford Broncos and F-series pickup trucks.

IH Oddball Disc Swap

I have been unsuccessfully looking for years for a way to convert my ’56 S120 International Harvester Travelall to disc brakes. The vendors who have disc brake conversion kits laughed and told me to upgrade the entire axle when I said I had a closed-knuckle frontend. However, the difference between a $500 parts investment with sweat equity and a $3,000-plus axle swap, with likely a near equal amount of sweat-equity, leaves only one answer for me. I have run across a vendor who was sympathetic and said he could get me discs that were un-drilled to solve the 6-lug configuration issue, but in-depth articles on the conversion were scarce.

Yesterday I sat down at the computer and on a whim did another Google search for “closed-knuckle drum to disc conversions.” Now, maybe I haven't worded the search exactly this way before, but for the first time ever, an article you wrote in May 2011 popped up on fourwheeler.com.

After reading the article and looking at the good number of photos, I was nearly in tears. Here, finally was an article with detail and tricks that I'd never found in any similar article before. I am a good shade tree mechanic and professional welder. I can build engines, transfer cases, transmissions, and differentials. I converted my first S120 to a Chevy 292 and built my own adapters to keep the International T-98 transmission, so there is not much I can't tackle.

To keep a long story short (too late?), finding a bolt-on mounting plate for the calipers seems very unlikely. The drum backing plate measures in at approximately 5/32-inch-thick. It looks, to me, that a little modification with machining and welding would do the job. Any reservations on that idea or suggestions of another route to take?

Bruce A. Frank
San Jose, CA

As you can imagine, a disc brake conversion kit for the front of a ’56 S120 International Harvester Travelall would not be a hot-selling part number. Of course there are still factory brake parts available from companies like Travelall Parts (travelallparts.com), and the company does have disc brake swaps available for other International Harvester vehicles. If you have the tools and skills to fabricate your own caliper mounts, there should be no reason that you can’t create your own disc brake conversion kit. Your idea sounds like a solid plan.

Grand to Moab!

I recently installed Old Man Emu suspension components on my ’97 Jeep Grand Cherokee with a V-8 and it’s a night and day difference. The new springs are a little stiffer, but they are the same height as the stock springs, plus the 2-inch spacers I added. The new Bilstein shocks absorb the bumps and the Jeep doesn't feel like it’s going to roll over anymore. I love the Jeep so much more now. There's still a clunking sound that happens when I turn the wheel all the way at low speeds. I need to figure that out.

Anyway, I found a factory front skidplate at the local junkyard. Since Mopar discontinued the nutserts used to secure the skidplates, do you know what the size specs are or if there’s an alternative part number for them? I would love to get my frontend and transfer case skidplates installed.

I'm definitely heading to Moab Easter Jeep Safari next year!

Tuan Huynh
Via email

A lot of the unibody Jeeps with solid front axles (XJ, MJ, ZJ, and WJ) have a tendency to clunk in the front end. The clunking typically comes from one of three different areas. Check the front track bar on both ends. The joints may be worn, the hardware could be loose, or the mounting holes could be wallowed out. Also check the drag link tie-rod ends for slop. The final place to check will be the front control arm bushings. Have a friend saw the wheel back and forth with the vehicle parked while you look for the location of the clunking. Sometimes the noise can be attributed to the tie rod or drag link twisting while the steering is being used. Replace any worn parts and tighten any loose hardware.

The factory skidplate can be attached with universal steel blind rivet nuts and the appropriate matching hardware. Companies such as McMaster Carr (mcmaster.com) offer blind rivet nuts in many different sizes. You should be able to find some that match up with the holes that are likely already in the unibody.

F-Series Disc Swap

I have a technical question about a disc brake axle swap. Does your project F-350 use an electronic speedometer with a sensor in the rear axle or a mechanical speedometer driven off of the transfer case? I have a ’95 F-250 and I was looking at doing the same conversion, but I need to know if it will work with my electronic speedometer. I may use a GM 14-bolt rear axle from around the same year. I’m looking for a disc brake rear axle to swap in that would be relatively easy without having to change the bolt pattern or run adapters. Any information is appreciated.

Coty Miller
Via email

We aren’t entirely sure what F-350 project vehicle you are referring to. However, the good news is that there are rear disc brake kits available for your factory rear axle. TSM (tsmmfg.com) offers rear disc brakes kits for the Dana 60, Dana 61, or the Sterling rear axle that could be found in the back of your truck. RuffStuff Specialties (ruffstuffspecialties.com) also offers rear disc brake kits that should work on your truck. Adding disc brakes to your axle will be far easier and less expensive than swapping in a new rear axle.

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