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

    Techline

    Technically
    I'm 42 and all I've ever been into is cars. I moved to Pennsylvania about 12 years ago, 30 minutes from Paragon before they closed it. I never ever heard of a front axle being called a "front rear" before moving here. Have you ever heard of such a thing? Also, isn't it true that although we all use the term LJ for the TJ Wrangler Unlimited, that term was made up and it's still a TJ?
    Sean Higgz
    Via facebook.com/JohnCappa4x4

    Interesting, I have never heard of a front axle being called a "front rear." However, I have heard of axle components being called very strange things, such as the centersection of an axle being called a "hog's head." It's understandable, because the assembly looks like the head of a hog if you imagine the pinion and yoke as the hog snout. Anyway, there are likely many other colloquialisms from the area that are different than what you are used to. Good luck with your new second language.

    As for the '04-'06 Jeep Wrangler Unlimited, technically speaking it's a derivative of the TJ Wrangler. Sort of in the same way the Sport, Sahara and Rubicon don't have their own designations. The Jeep engineers who developed the '04-'06 Wrangler Unlimited and worked on the '97 TJ will indeed tell you that the LJ designation is made up and that it was never used during development or production. At least that was the story many years ago. In mid-2004 when I got my hands on a short-term test Wrangler Unlimited from Jeep, I noticed a build tag on the front crossmember. This metal tag had LJ stamped in the model box. It also had 4WOR stamped on the tag. The Jeep was special-ordered and slated to enter into 4-Wheel & Off-Road's 4x4 of the Year competition. I followed up by checking the build tag in the same location on the Jp Magazine Wrangler Sport project Jeep and found it had the TJ designation stamped in the same box. Of course, the Jeep engineers I spoke to could not explain my findings at the time, so the LJ designation stuck, despite their chiding about being wrong about the new designation. Today, it doesn't really matter; the TJ Unlimited is forever known as an LJ, regardless of if it's incorrect or not.

    Explorer Traction
    I have more of an opinion question than a tech question. Given the choice of any traction aid on the market, what would you choose for a front TTB Dana 35 under a Ford Explorer? You can't say ARB Air Locker!
    Kyle Edwards
    Via facebook.com/JohnCappa4x4

    Selecting a traction-adding device for the front or rear of your 4x4 requires a lot of thought and evaluation of several factors. These factors should include tire size, engine output, automatic or manual transmission, how you plan to use the vehicle off-road, and even driving style.

    The '90-'97 Ford Explorer Dana 35 TTB axle enjoys more traction-adding differential options than many less popular axle assemblies, but not all of these devices will be a viable option for your specific application. Given that the TTB Dana 35 front axle isn't exactly known for being bulletproof, I would recommend treading lightly into the traction-adding device waters. The steering U-joints and axleshafts could easily become collateral damage during your 4x4 fun with the increased traction offered by a locking differential. With that said, if you need a full locker, I would recommend a selectable locker that you can turn off when it's not needed. This will decrease the wear and tear on the entire axle assembly. Given that parameter, the only selectable locker options I know of for the TTB Dana 35 are the ARB (arbusa.com) Air Locker, Auburn (auburngear.com) ECTED, and the Eaton (eaton.com) ELocker. If you don't like the air-operated ARB, you can go with either the Auburn ECTED or the Eaton ELocker. Both are operated via a 12V switch and wiring. The Eaton ELocker functions as an open differential when unlocked and a full spool when the 12V switch is flipped. The Auburn ECTED has the advantage of performing as a limited-slip differential when unlocked and a full spool when engaged. The limited-slip feature is nice to have on-road in snow and ice. This is especially true in a front axle application.

    Regardless of which traction-adding device you chose, you may want to consider other TTB Dana 35 axle upgrades. For example, if your Explorer features automatic locking hubs, you should seriously consider swapping them out for some manual locking hubs. The manual locking hubs from companies such as Warn (warn.com) are considerably more reliable than the auto locking hubs, even more so when backed up with a locking differential and bigger tires.

    Balance Me
    What is the best method for balancing larger wheel and tire combos aside from hammer-on and/or stick-on weights? I've seen a lot of things from airsoft BBs installed in the tires to the powder you throw in baggies. I'm in need of rebalancing my wheels and tires since I believe one of mine has been unbalanced since it was mounted.
    Matt Houck
    Via facebook.com/JohnCappa4x4

    Balancing large tires and wheels can be a tricky endeavor, and unfortunately nearly impossible with some used tires. The biggest offenders are bias-ply tires and radial tires that feature more durable sidewalls. These tires can develop flat spots when the vehicle is parked for any length of time. That time shortens as temperatures cool off. So, let's say you roll into your local tire store after driving 30 minutes or so to warm the tires up, park, wait in line, fill out the required paperwork, and wait, all while your tires cool and develop flat spots. The tech removes the tires from the vehicle, tosses them on the balancer with flat spots, balances for the flat spots, and then reinstalls the tires. You drive on down the road and quickly notice the tires are still imbalanced once the tires warm up again and the flat spots work themselves out. This was a mind-numbing issue that occurred regularly when I was mounting and balancing large-diameter tires at an off-road shop. Also, regular off-road use often causes luggy tires to shed their tread unevenly, exacerbating the big-tire balancing dilemma. The best way to combat this is to utilize a constantly adjusting tire balance solution like those that you have mentioned. Personally, I prefer tire balance aids that don't bounce around inside the tire and wheel, which could cause damage to both the wheel and tire air chamber. Plus, your tire guy will absolutely hate you if he breaks down one of your tires and blows balancing powder or Airsoft BBs all over his shop.

    You might take a look at hub-mounted tire balancing products, such as those from Centramatic (centramatic.com). They are designed to constantly maintain proper wheel and tire balance, regardless of tire wear or chunking, and are available for many popular lug patterns. They also can't be torn off in the mud and rocks like stick-on and pound-on wheel weights.

    TH350 Trouble
    I have a TH350 automatic transmission. On my last wheeling trip it all of a sudden stopped taking off in drive. I can pull it down in to First gear and run through the gears and it runs fine. It was not a manual valve body before the trip, but it sure acts like one now. What are your thoughts?
    @curryheath
    Via Instagram @cappaworks

    There are a few things that could be causing your shifting issue. You should start with the simple stuff on the exterior of the transmission and then work your way inside. Make sure the transmission is filled with clean fluid and check the kickdown cable and shift linkage for proper adjustment. If you're driving it hard, sometimes the burnt clutch bits can get into the governor and gum up shifting operation, causing a similar problem to what you are experiencing. Remove the governor cap on the side of the transmission, pull the governor out, and clean it and the pocket well. Get all the burnt clutch bits out of the mechanism. Reinstall the governor and see if that fixes it. If not, the next step is to remove the pan and make sure the valvebody bolts are snug and the valvebody gasket is in good condition. If all of this fails to remedy your shifting issue, it's likely time to remove the transmission and perform a teardown and rebuild—because you have a bigger problem somewhere inside.

    Ford 60 Front Matchup
    I'm trying to find a matching rear axle for my '04 Ford Dana 60 front axle. I prefer a Sterling 10.50-inch. Is there any preferred year for the 10.50, and what's the best way to spot one compared to a 10.25?
    @loganlikesjeeps
    Via Instagram @cappaworks

    The Sterling 10.50-inch was used in '99-up Ford Super Duty trucks; the 10.25-inch was used prior to that. If you are building an extreme off-road rig, the Sterling rear axles have never been a solid swap. Under heavy use with big tires, a lot of weight, and plenty of traction and power, the axletubes can spin in the cast centersection, breaking the plug welds or cast portion of the axlehousing. For a daily driven 4x4, the Sterling 10.50 is fine, but I think it will be worth the effort to use something like a GM 14-bolt rear axle if you are working on a trail rig. Of course, you'll need to alter the lug pattern on either your front axle or rear axle so that they match. Your Ford Dana 60 will have the 8-on-170mm lug pattern and the GM 14-bolt will have the more common 8-on-6.5-inch lug pattern. You can convert the front axle to 8-on-6.5 with unit bearing replacements or a fixed-spindle conversion from companies like Currie Enterprises (currieenterprises.com), Dynatrac (dynatrac.com), and Spidertrax (spidertrax.com). You'll then have to have the rotors redrilled to match the new front lug pattern. The other option is to add wheel adapters to the 14-bolt from a company such as Wheel Adapters USA (wheeladaptersusa.com). These will convert the 14-bolt to the same 8-on-170 metric lug pattern as the front axle. The adapters will also increase the width of the 14-bolt by a total of 3 inches, which typically will better match the width of the wide Ford front axle.

    Undesirable Axles
    Let's talk about less desirable front axles. I swapped a 10-bolt GM front axle and a 14-bolt rear axle under my CJ-7. What are the weak points of the 10-bolt? Mind you, the Jeep has lockers front and rear and rolls on 37-inch tires. The Jeep is running the 258ci inline-six, a T-4 manual transmission, and a Dana 300 transfer case. I will eventually be swapping the gas engine out for a Mercedes OM617 diesel. I'm kind of an abusive driver. So far, I've only lost a driveshaft U-joint at a relatively high speed.
    @ryan_f_veitch
    Via Instagram @cappaworks

    Axle survivability depends on many factors. Some drivers could make a combo like this last an eternity, while others could turn it into a metallic gear-oil mist in mere seconds. Behind the hands of a moderately abusive driver, it would be my guess that the axleshaft U-joint caps will wallow out the bores in the axleshaft ears. Once the bores open up, the assembly is not long for this world. Slightly more aggressive driving will either break an axleshaft U-joint cross or cause an axleshaft to fail near the splines. Ultimately, it's hard to predict if the U-joint will fail before the short-side inner axleshaft. This will depend on the specific situation, the traction available, how far the steering is turned, and weight distribution at each wheel. The reason the short-side inner axleshaft typically fails before the longer inner axleshaft is because the longer axleshaft can flex and twist more before the point of failure. Lucky drivers will sometimes only shatter the outer stub axle or destroy a locking hub. The good news is that all of these parts can be upgraded to survive behind 37-inch and even bigger tires.

    There are several companies that offer heavy-duty chromoly axleshafts and stronger aftermarket steering U-joints. However, traditional steering U-joints and axleshafts will still be plagued with the problem of being weaker when the steering is turned one way or the other than they are when the wheels are pointed straight ahead. For even more axleshaft strength and durability you can upgrade to CV-style axleshafts from RCV (rcvperformance.com). The RCV axleshafts are said to be twice as strong as OEM axle shafts, and unlike U-jointed axleshafts, they're designed to be just as strong with the steering pointed straight as they are when the steering is turned to extreme angles. The RCV axleshafts will also eliminate U-joint binding to allow smoother power transfer to the ground when the steering is turned. This is especially noticeable on harder surfaces like Moab slickrock and granite slabs. RCV also offers 300M locking hub upgrades as well as drive flanges for the ultimate in power transfer to the wheels.