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com and So to begin I'll briefly explain what a differential is and what it does and essentially it's a mechanism found inside the axle of your ve So as power is applied to the axle it needs to allow the wheels to spin at different speeds to prevent the tires from scrubbing or the axle from binding and so most ve So here we have an open differential. T 5 ton military Rockwell axle. It'sitting here on its side. It's normally installed horizontally and there's another carrier half on top of it. But t On each side you have a side gear. You'll notice that inside it'splined because that's the gear where the axle shaft slides into so ultimately these are the gears that are turning your tires. Inside of the differential you'll see four spider gears or differential pinion gears and they're attached to the carrier on t So as the carrier turns it moves those pinion gears with it. So as power is applied to the differential there would be a ring gear on here. The drive shaft would come in and it would turn the axle. So as you'd notice when both tires are spinning at the same speed, the entire unit is moving as one assembly and the ve When the ve It's all slower than the actual movement of the differential so both tires are still moving forward but internally the gears are actually moving opposite each other. So if I hold t So t It wouldn't normally happen there's just much less friction put on the problem with it is as soon as you get a tire up in the air or you get a tire on some ice, the tire that has traction will hold the differential will still turn but what's happening is the other wheel is spinning freely and no power is being transmitted to the wheel that has traction. So that's the problem with an open differential and to solve that you need some form of locking mechanism or somet So the first type of differential that we'll go over that does that is called a limited slip differential. Here we have a limited slip differential often abbreviated as an LSD and called a POSI or a Track Lock. They're quite easy to identify because they'll all have springs on the inside. T Between the side gears and the carrier you'll find a small clutch pack. These are very similar to what you'd find in a manual transmission just on a much smaller scale and as the clutches spin against each other they create friction. And what that friction is trying to do is it's trying to keep the side gears spinning together at the same speed and keep the entire internal assembly spinning as much as it can at the same speed as the carrier case. So what that does is it tries to keep power going to both wheels even if one wheel loses traction, goes up in the air or is on ice. The tighter the clutch pack is put together and most limited slips especially aftermarket versions are tuneable so you can adjust the springs, you can adjust the attraction fluid in the differential and you can adjust the friction of the clutch plates. So most limited slips should be tuned for the application and so the tighter the clutches are, the more it'll want to move the axle in a straight line and the looser they are the more it'll allow the ve So one issue with a limited slip differential is the same that you'd find with a manual transmission is that over time the clutches will wear out. So most limited slips can be serviced. From my experience they'll normally last about 20 to 30,000 miles before they kind of wear out and become an open differential. So they'll never fail. When a limited slip differential fails it basically becomes an open differential and you can live with that for as long as you want. But if you're going to be installing a new differential that reason is why I would not recommend why we don't sell limited slips. If you're going to be putting in the time and the money to install a new differential I just don't Especially since there is a better product that does the job better is an all gear design and doesn't need to be serviced pretty much at all. And that type of differential is called a torsion. A torsion style differential Now it's an absolutely brilliant design. It just happens to be pretty tough to explain so I'll try and do my best with the principle of a torsion is it works on the idea that a worm gear can turn a spur gear but a spur gear cannot turn a worm gear just a little bit more toned down for t So on the torsion carrier to w The worm wheels have spur gears on either end and they lock them together at a one to one ratio just So whenever you're taking a turn one wheel moves one way, one wheel moves the opposite way in relation to the case. So these gears are what cause that one to one ratio. So inside of the differential we have a pair of worm gears. Inside of those worm gears you've got the axle shafts and you can already see it's a little tight but when I move one direction the other one has to move the other direction. So that's that one to one ratio with those axle shafts. So that alone would make you think that this differential works just The difference is with these worm wheels as they push on those worm gears on the inside they're pus If you have two gears at 90 degrees apart from each other when one spins a try and turn the other it takes a lot of force and you've got to overcome that friction. That's the principle of a torsion. So you'll have conventional oil you can use synthetic that's a common question that we get it just kind of takes a little bit more work to lock up but when you've got one tire that'spinning freely and another one that has traction they bind against each other because they're trying to move faster than that one to one ratio. When they lock up these gears have a much harder time turning the internal gears and it basically more or less turns the unit into a spool all by itself. No switches no electronics no clutches not So without going into too much more detail that's pretty much the function of a true track when you've got one tire that's on ice and another tire that's on dry pavement as soon as that tire on ice starts to spin and spin faster than that two to one or one to one ratio it will bind up the true track and force the tire on the pavement to move the ve Now one issue is because it's not exactly a worm gear and you can get them to turn each other when you do get a tire up in the air it will spin freely. So the solution to that is you do what the military does all military H So again you can see why this is such an amazing design and this is by far in our way our best selling differential for applications that don't require a selectable locker or a spool or a Detroit locker where Selectable lockers are differentials that normally act as open differentials yet they've got an internal locking mechanism that when engaged will force both axle shafts to spin together similar to a spool. So there's three common types you have the manual aux locker you've got the air operated ARB air locker will also show you the Yukon version called the zip locker and then there's the Eaton E locker that's an all-electric locker. So the benefit of a selectable locker is that during normal operation it acts When you're done you disengage the locker and you've got an open differential again. We'll start by going over the air lockers in a bit more detail. These are our air lockers we've got the ARB air locker and the Yukon zip locker they both work on the exact same principle in that air is supplied to the unit it's fed through a pinhole in one of the bearing journals and then pushes up on an engagement collar that will lock one of the side gears to the case thus locking the entire internal mechanism. On the ARB that feed is on the ring gear side right by the engagement collar whereas on the Yukon locker it's on the opposite side and then it pushes up or down on t With them being air operated lockers you will need an air source w Normally that's an air compressor although you can use a CO2 tank that'll feed through an air line into an electric solenoid that can be open and closed by a switch that you have on the dash. That air line is then fed to a collar that sits right by the carrier bearing and feeds air to that pinhole in between two O-rings on either side so as the case turns it'sealed and that air goes into that pinhole. So air lockers are extremely reliable however you do have to be very careful during the installation process because you can see there's a lot of parts involved in making the lockers work. So when you're running their air lines make sure to keep them away from heat and moving parts a pinched or leaking air line will cause the locker to fail. Make sure you've got good electrical connections fuses that blow wires that get chafed will also cause the locker not to work. And then also during the installation of the differential itself you have to make sure that there's no debris or dust or anyt With that said between the two we definitely saw a lot more ARB air lockers than we do the Yukon. Personally I always prefer the ARB as well I t I run these in my Land Cruiser also in one of my Rockwell Axles but I would not hesitate to run the Yukon. They are a little bit cheaper especially if you wait for some of their s They are backed by a six year warranty w But if you install them correctly and pay attention to those t With that said let's move on to E-lockers. The E stands for Electric and that's exactly what it is. It's powered by a 12 volt current that will lock or disengage the mechanism. On your dash you'll install a switch. When you turn the switch on it will send that current to the locker that will lock it. You turn the switch off and it will disengage it. You've got an open differential again. So very simple and also very easy to install. It's the easiest of all the selectable lockers because all you have to run is a small wire to the axle. The locking mechanism itself is actually quite cool and as you'd expect it's powered by an electromagnet. You'll see that it's fully sealed in epoxy and then on t Inside of the differential there are two roller cams in w So the ball bearings sit in these cams and then there's the other half on the inside and they sit together and the two collars are flat against each other when the lockers in the off position. When you apply power to the magnet it will push everyt When they push apart inside of the differential they'll push against these springs and those pins push down inside of that differential and into the side gear. So you'll see these recesses inside the side gear that's where those pins push into. So the actual locking mechanism is extremely tough. It'six pins pushed inside of that side gear. One downfall to t I mean there's really not The problem is when the lockers engaged and the power is applied to the magnet the axle still has to turn about a quarter turn before the bearings can ride up and push those pins into the side gear. The other issue is that when you're moving forward and then you go to a stop and have to move backwards the bearings have to move down to their resting position and then ride all the way back to engage in the backwards position. So t Now the design is extremely reliable. You see that there's really not However, because of that slack t For that I would recommend either the air locker or the mechanical locker or even a Detroit locker that we'll cover in a little bit. But t I sell a lot of E-lockers paired with Eaton True Tracks because they kind of make the ultimate combination for a truck, a True Track in the rear and then an E-locker up front that you can engage when you need it. So very, very good design. They are affordable for what they are and very easy to install. So for a street driven ve So with the E-locker covered let's move on to the final selectable locker and that's the manual aux locker. T It is a manually engaging locker so there's no 12 volt electrical supply or air supply needed to engage or disengage it. It's all done mechanically. You have a s Inside of the differential you'll notice we have t When I move the lever from the open to the locked position that fork moves inward. What it's doing is it's moving an engagement collar very similar to the ARB air locker that I showed you. It's moving that engagement collar over one of the side gears locking it to the case. That in turn locks all of the internal gears together and locks the axle shafts together. To disengage the locker you simply move the lever into the open position. Now the mechanical nature of t I just love being able to move it from one to the other and knowing what position the locker is in and knowing that it's actually done it. With an air locker or an E-locker you flip a switch and you don't know if you've got a fault or an issue. With the aux locker Additionally, it can stay in the locked position indefinitely. So because there's no air supply or constant electric source needed to keep it engaged, when that means that the aux locker is either an open differential or literally a spool. It will stay as a spool and be just as reliable. The s And then for additional security you can spin down on that s When you're ordering an aux locker you do have to measure for a s Keep in mind that these are not very flexible so you've got to make sure that you get nice long winding curves and that of course keeps the s There is some leniency in the length of the cable that you order but if you order the wrong size don't worry about it, we offer a free exchange on those. The aux locker also comes with its own differential cover, a very heavy duty cast iron differential cover to w So you get a free differential cover with all orders. Also aux makes what's called their drive away lock and t We include these free with all aux locker orders and it works well as a redundancy. So if the aux locker cable gets damaged or torn you can remove the cable, bolt t So they call it the drive away lock because if you have a failure you can still drive away with t Or forget about the so that feature, the fact that it can stay in either position for long periods of time and also you have that positive engagement makes t It's also very well made, most I believe actually almost all of the components in t We've had very good luck with aux working with them. We've sold many of these units without any issues. So if you're looking for a selectable locker and you It's With that said that takes care of selectable lockers so let's move on to the Detroit locker. The Detroit locker is probably the most well known type of differential locker. It's been around for what seems So it's a bit of confusion there. I get a lot of customers asking to order Detroit lockers not knowing how they work or what their benefits and drawbacks are and realistically a Detroit locker is not really a differential at all. It has no internal differential gears. It is sometimes called a gearless differential but in my opinion it works far more So let's take a look at how they work. The Detroit locker is made up of three wheels that have these radially cut ratchet style teeth on them. They are all pressed together. There's two springs from each side pus So in its resting position when power is applied to the Detroit locker it's immediately sending it to both wheels equally. Well, as we've covered earlier when a ve So when that happens you get t You'll see them here. It will ride up on those internal cams and skip a tooth and then it will skip another tooth as long as it needs to in that turn. So what's happening is the differentiating force in a Detroit locker or the function of the Detroit locker is actually disconnecting one of the axle shafts entirely. What also happens is as you can imagine every time that it clicks over it's making a noise. You get t Another issue with it unfortunately is due to the design there'slack built into the unit. That means from a standstill when you From forward as soon as you let off the gas it will click backwards so it's a little sloppy to drive on. However with those faults being a little bit noisy and a little bit sloppy it works amazing off road. A lot of desert racers use the Detroit locker. I t For the street I'd be really cautious recommending one especially for somet They are street legal you can drive them there's not any issues but just It is going to act a little bit differently. Mainly in different type of traction conditions so if it's raining or if it'slushy or if it's a bit of snow or ice the Detroit locker doesn't really know or doesn't really disconnect with any finesse. It will either be locked or it will be open and so a very common issue with a Detroit locker on a street driven ve It will either stay locked for a little bit and then all of a sudden disengage or stay disengaged and then all of a sudden lock up so you've got to be careful. After heavier vehicles There are two different styles of Detroit lockers. You have the full case style w T You don't have to remove the gears. You don't have to do any gear setup. You simply remove the diff cover, remove the spider gears and the cross shaft, replace it with t It's a slightly different design, works in the same principle but these work really well for front axles if you've got selectable hubs or if you're on a budget or doing the work yourself and you want to keep it simple. There is another Detroit locker made by Yukon. It's called the Grizzly Locker. I've taken them apart and looked at them side by side. In fact, these are the internals from a Yukon Grizzly Locker. T I've really had to look long and hard to try and figure out any differences to them. I've read the marketing materials. I've talked to both manufacturers. They both claim that theirs is better than the others but I've sold a lot of each and as long as they're installed correctly and used in the proper application they are extremely reliable. They get the job done so I would just order w They're both very, very well made but I t So that's a Detroit locker and the last style of differential left would be the full spool. The last style of differential that will go over is the spool and it is in fact not a differential at all. It is literally a chunk of steel that's been mac So as you can tell a spool will always send power to both axle shafts equally and has no differentiating function. For that reason it really is off-road only. You should never drive a spooled ve Street trucks, desert racers, We still prefer the Detroit locker just because it gives you that bit of a fuse function to it. Kind of helps with reliability, helps prevent some damage but not A smaller version of the spool and a little bit less involved and less permanent is a mini spool and this is a lot T You just remove the diff cover, remove the spider gears and the cross pin, put the mini spool in and you've got a spool. And what's nice about that is if you decide that you don'then if you're on an absolute budget and don't want to spend anyt These are spider gears that I had left over from a Rockwell axle I had. You weld them together. You don't have to go too crazy but I've seen people fill the entire unit together. I've gone ahead and of course painted it w If you just weld the spider gears together you essentially have a very cheap, simple and effective spool. So even in off-road applications I would still only recommend a spool in the rear. Up front in a solid axle application there is just way too much binding and a lot of times if you're out in the trail even if you've got a selectable locker engaged it's really hard to make tight turns w So the spool should never really be used up front if you need somet So with spools covered I t I know that t Just like with our other videos if you've got any questions feel free to You can always email me at ben at FilthyMotorsports. com. Check out our websites FilthyMotorsports. com, Crawlpedia. com and as always