Words and photos by Bryan Irons @bryanirons
If you have wheeled your rig, even in moderate settings, you know that traction is everything. All the power and driving skill in the world is for not if you can’t get it to the ground. There are MANY different differential upgrades that can be made to improve the ability of power getting to dirt. Most base level 4x4’s come with what is commonly known as an “open differential” and they work beautifully for vehicles with equal traction on both the left- and right-hand side. While cornering, they allow the outside tire to travel a different distance/speed than the inside tire in a seamless, mechanical action. Our problems occur when traction on either side of the vehicle is different, like climbing over loose surfaces or undulating trails. We see it plenty of times on the trail as it is easy to spot with one tire turning, and the other just sitting there not helping at all. If you have been in this situation, this is normally when you start smelling the torches and see the reflected light from the freshly sharpened scythes of the “go buy a locker” mob. Don’t worry; we’ll see if we can help out.
Bryan Irons
If you can guess what this carrier is from, get in touch with us for a chance to win a General Tire Edition Portable Jump Starter. The pop can and chip bags can be used for sizing, or maybe we just needed to add some colour to this picture!
“What are the alternatives?” you ask? If you find yourself contemplating the need for added traction, you’re in the right place. We’ll go over a few options here with our personal experiences and let you decide. Our advice is always to have a chat with some wheeling guru’s and watch how their rigs behave on the trail and in the streets, and remember that “compromise” is the word to the wise.
Starting off with “selectable lockers” such as those factory options in some Toyotas, Hummers, Dodge/Ram Power Wagons and the belly button ubiquitous Jeep Rubicon to name a few. The selectable locker allows the driver to manually select when the right and left axles shafts will be “locked” together in unison and when they can act like that of an open differential. Availability in the aftermarket is abundant, but the price is high along with a more complicated installation. Not to mention that you now have switches and gadgets to operate on the trail as well.
Next in out list are the “Auto Lockers” and as the name implies, the mechanical springs and gears perform a ratcheting action to keep the left- and right-hand sides of the axle turning the same speed when power is applied, but do allow some tire speed discrepancies while not on the gas. They work well, are simple, but can have some odd handling characteristics especially with high power, manual transmissions and short wheelbases. “Lunchbox lockers” also fall into this category with a cheap buy-in and easy installation. Longevity on the Lunchbox style is suspect, as the components do wear, and they rely on the strength of the original carrier design.
“Limited Slip” differentials come in many factory vehicles in numerous styles and designs with the same goal, which is to limit the speed difference between the left and right hand axle shafts by the use of friction. Typically, clutch materials and spring pressure is used to actuate the limited slip and they go though life mostly unnoticed. The added traction is mediocre and most clutch style Limited Slip differentials are toast before 60,000 kms and act as an open differential. Not our fave, but they have their place and are GREAT in snow and loose sandy materials when they are new. Gear driven limit slips negate the wearing issue but they still are not a true “locker”.
This leaves us with methods to permanently lock the axle shaft together, FOREVER. “Spools” are a by-product of too much power, not enough traction and a very low budget. Ultimately, a full case spool is a single chunk of steel that replaces the center carrier of your differential. No external components or special oils are required and they provide predictable traction. For those on an even tighter budget, you can look at “Mini spools” which simply replace the standard differential gear cluster with solid pieces of metal. Spools offer the ultimate in traction and simplicity, but chew tires on the street, make turning radiuses larger and can place huge strains on your vehicle’s driveline components. If there is a weakness to be had, a spool is sure to find, and exploit it. If placed in the front axle of a vehicle, plan on the above symptom to be even worse, and kiss the notion of street driving goodbye unless you have locking hubs.
All the above mentioned require some kind of cash outlay and possibly some professional installation of some sort. As per our previous ramblings, we hardly make enough dineros at this job to buy two-ply toilet paper. So, in the spirit of uber-cheapness, we’re going to show you how to spend next to nothing to get yourself the ultimate in traction. At this point, you may be thinking “Lincoln locker”, which is a term used when you simply weld the living begesus out of the spider gears in your differential. Apply named by the Lincoln brand welder, it creates a “poor mans spool”. We’re not going to do that, we’re going to make a “Miller Spool” (AKA Fozzy locker) where by the differential spider gears are removed, welded on a bench and placed back into the carrier…. With a Miller welder in our case! The end result is a basic spool that can be easily removed once we come to our senses and grow up, if ever.
The advantages of using the age old DIY traction adder such as out Miller spool are plentiful, the first of which is the simplicity and basic outlay of cash, plus, if you have an extra set of carrier gears like we have, you can have amazing traction on the weekend and swap the original spider gears in for highway driving with no added tire wear or component stress. We really need to lay down the law at this point and let you know that this is a dirt cheap, booty fab, last kick at the can traction adder for a vehicle that should see little or no time on the street, especially in a front application unless you have locking hubs and a lucky rabbits foot.
Follow along down into the dark corner of wheeling shenanigans and tomfoolery as we attempt to get something for nothing in a last-ditch effort for off road supremacy. For those of you with a keen eye, hit us up on Facebook and let is know what differential you think we are working on, what type of differential we are starting with (open or limited slip), and what gear ratios fit this carrier for chance to win some dusty relic that editor Mack has managed to squirrel away from us in his office.
Miller Welders www.millerwelds.com
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Bryan Irons
With the open carrier assembled and somewhat cleaned, start by marking the gear tooth openings that are not in mesh with other cluster gears. This can be done with the carrier still in the vehicle, but we find the extra time to get it on the bench worth it. We also removed the ring gear in this instance but it is not always necessary.
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Bryan Irons
This particular carrier uses a roll pin to retain the cross bar. Some use a shoulder bolt or other retaining methods.
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Bryan Irons
A pin punch and hammer were used to drive the pin out. They can only go one direction, so pay attention.
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Bryan Irons
With the roll pin out, you can drive the cross bar out.
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Bryan Irons
Turn the entire cluster 90 degrees to remove all the pieces. Watch for thrust washers and not where they came from.
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Bryan Irons
With he cluster gears out, make sure your markings are legible. If you weld in the wrong spot, you’ve got yourself a nice set of paperweights to go with that ashtray you made when you were 6.
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Bryan Irons
We used our Ingersoll-Rand die grinder to clean up the welding surfaces. We also wiped them down in acetone to make sure the welds stick.
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With out Miller MultiMatic 200 set to “core of the earth” for heat and our side gear splines covered to keep welding boogers out, it was time to make the big leap.
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Bryan Irons
It may take a few passes to fill in the gear root, but take your time and get a strong weld in there. An ugly booger weld could break loose in the future and make a mess of the bearings in the differential.
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Bryan Irons
You may be convinced to try and quench the gears and cool them down super fast. Unless you know that you can get the hardness of the gears back to factory specs, we would advise against this. We just let them cool at a normal pace.
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Bryan Irons
Once cool, you can grind away any extra metal that may inhibit getting the gears back in the carrier. We use an old belt sander, but an angle grinder will work just fine.
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Once cool and clean, assemble the carrier and install it back in your rig. It’s time to go have some ghetto wheelin fun!