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How It Works: Lunchbox Lockers
The Spartan Locker, USA Standard Gear’s lunchbox locker, provides game-changing traction at a low cost. A locker physically joins the drive axles together so they deliver an equal amount of torque to each tire, regardless of available traction. Lockers come in two flavors… selectable or mechanical. What are the Different Types of Lockers? A selectable locker is an on-demand unit that the driver activates electronically or pneumatically via a cockpit-mounted button. A mechanical locker is always active, providing traction 24/7. The Spartan Locker and Yukon Grizzly Locker are mechanical. The Yukon Zip Locker is an air locker or selectable locker that uses a pneumatic system for actuation. The Spartan Locker is flanked by a Yukon Grizzly Locker (left) and a Yukon Zip Locker (right). In mechanical lockers, also called automatic lockers, on-throttle driving conditions, where load is applied to the differential, induces locking. Off-throttle situations, where the diff is unloaded, leads to a partially unlocked unit. When the vehicle turns and the two wheels on the axle turn at different speeds, the unit makes a clicking sound as the square-cut side gears move over and past one another. This ratcheting sound can be loud and is why mechanical units may not be best suited for vehicles that spend a lot of time on the street… it all depends on how sensitive your ears are. What’s for Lunch? The lunchbox locker name is a loose reference to that handy mid-day meal carrier we all know and love. Just as you can put a different kind of meal in your lunchbox, the lunchbox locker allows different internals to be put in your differential… the internals being the lunch and the differential carrier being the box portion of the equation. Lunchbox lockers are not a singular component you swap in, but a collection of parts that converts an open differential carrier (and only an open differential carrier) into a mechanical locker. A typical Spartan Locker consists of a pair of drivers, two spacers, two side couplers, four alignment pins, four pre-load springs, a hardened cross-pin shaft, a roll pin, and installation wires. Depending on the differential carrier design, your Spartan Locker could have more or less components in the box. Pros and Cons of Lunchbox Lockers Great grip on a budget is the lunchbox locker’s calling card. Price is the biggest pro for the lunchbox locker. They cost less than half the price of an air locker, and remember this is before factoring in the cost of a pneumatic operating system. The lunchbox locker is about a third of the price of a large-frame mechanical locker / automatic locker. Going with a lunchbox locker also pays off when it comes to installation. Since the process is less labor intensive than a large-frame locker installing a lunchbox locker costs less. The savings can be even more substantial if you handle the install yourself. The Spartan Locker's patent-pending design replaces the spider gears in a standard carrier case, does not use the thrust washers, and has a revolutionary spring-and-pin design that makes installation quick, easy, and much cheaper that other types of lockers! Further, in some cases, the install does not require the removal of the differential. A disadvantage of this is the lunchbox locker relies on the factory carrier for strength. Large-frame lockers, like the Grizzly and Zip, replace the carrier as a single unit and their case is constructed from a much stronger alloy steel compared to the factory carrier. Being locked all the time, mechanical lockers can cause accelerated tire wear. As with many modifications, it’s a game of trade-offs. Installation Tips and Tricks If you’re able to remove the spider gears with the carrier still in the housing the installation can be done without removing the carrier from the diff. If it’s too tight in there, the diff will have to be removed. Spartan Lockers come with a highly detailed installation manual that includes tons of photos and step-by-step instructions. The manual addresses installation in a variety of differentials. Basically, the Spartan Locker’s drivers are assembled with the alignment pins and springs installed. The installation wires keep the assembled unit together until installation is finalized then they’re removed releasing the spring tension that’s needed to operate the unit properly. Spartan Locker Installation Quick Tips For Use in Open Differentials Only Remember to Re-Install Carrier Shims and Bearing Caps in the Same Place Punch Mark Bearing Caps to Indicate Which Side to Install Them On Be Sure Tires are Same Circumference to Ensure Proper Locker Engagement Are Lunchbox Lockers for You? Vehicle usage is the tipping point. Not just how much your rig will see the street where the boisterous operation of the lunchbox locker comes into play but off-road usage as well. Your expectations on the trail; and how much you’ll be demanding from the driveline come into play. If you’re staying on the trail with moderate hill climbing, scrambling over rocks, and the like, the lunchbox is a good call. If you plan to be more aggressive and looking to get into some extreme situations where a great deal of torque and load shocking are the norm, a large-frame locker may be the way to go. When it comes to the ratcheting and clunking sounds the unit makes, read up on the subject. Some users report the sound isn’t that intrusive, others say the noise fades with use. As we indicated before, the performance game is made of trade-offs… but the payoff is big. Spartan Locker Highlights Big on Traction, Low on Cost For Use in Open Differentials Only Patent Pending Design Replaces Spider Gears Low-Cost Shop Installation - Can be DIY Installed Reliable 100% Lockup Power Transfer Features Heat-Treated 9310 Steel Internals for Enhanced Durability Shop Spartan Lockers or contact us at 866-631-0196
How It Works: Positraction Limited Slip Differentials
Positraction or Limited Slip Differential Limited Slip Differentials (LSD) significantly increase the traction and performance of Jeeps, trucks, 4×4s, and RWD vehicles on the street, at the strip, or on the trail. Positraction is what General Motors called its limited slip differential, the term has come to refer to LSDs in general. How Do Limited Slip Differentials Work? An LSD’s main job is directing torque where it’s needed. When you’re driving in a normal manner a positraction limited slip differential is pre-loaded and provides equal traction to both wheels. Mashing the throttle, taking a tight corner aggressively, or working through loose gravel trails will result in the limited slip differential limiting wheel spin across the drive axle by permitting the axle shafts to spin at different speeds while continuously trying to balance the application of torque between the two axles. This results in transferring more power to the wheel with the best traction which enhances the grip, control, and the predictability of the vehicle. Are There Different Kinds of Limited Slip Differentials? Yes. In their static state, when traveling in a straight line where wheel speeds are identical on both sides, all limited slip differentials provide equal traction to both tires. The difference between LSD types is how each unit applies torque when additional traction is needed. Clutch-Type Limited Slip Differential In regular circumstances a clutch-typeunit, like the Yukon Dura Grip, uses an array of springs to apply pressure to the side gears which puts pressure on the clutch packs in the outer part of the carrier. Both axles get equal pressure and both tires get equal traction. When a tire starts slipping, the clutch packs are engaged with differing resistance. The clutches compensate to maximize traction between the tires, transferring more torque to the tire that has the best grip while reducing torque transfer to the tire that has less grip. All Dura Grip units are four-spring designs built with a high-strength nodular iron case, forged 4320 chromoly spider gears, and high-quality composite clutches. The Dura Grip positraction limited slip differential is engineered for long life and is completely rebuildable. The clutches can be replaced to bring the unit back to its original performance level, or different clutches and spring rates can be used to fine tune the Dura Grip’s performance to better match the style of driving/racing you are doing. The Yukon Dura Grip is transparent in its traction enhancement, coming online only when the edge of adhesion is reached and slippage occurs. This makes it ideal for daily drivers that will be driven hard on the street and see extended action on the trail or at the track. Yukon Dura Grip Specs Four-Spring Clutch-Type LSD High-Quality Composite Clutches Tough Nodular Iron Case Forged 4320 Chromoly Gears Fits All Gear Ratios Choose from Four Levels of Spring Pressure When Rebuilding Each Unit is Quality Tested and Assembled in the U.S.A. Recommended Gear Oil: Non-Synthetic 80W-90 GL-5 1-Year Warranty Against Manufacturing Defects Gear-Type Limited Slip Differential A gear-type LSD, like the Spartan Helical LSD from USA Standard Gear, have no frictional surfaces to initiate torque transfer. It uses floating helical-cut worm gears that operate in pockets and mesh together. Under normal driving conditions this type of LSD acts like an open diff. When acceleration or wheel slippage occurs, axial and radial thrust is applied to the helical gear pinions in their pockets. Under these loads, more torque is transferred to the tire with the best traction, in a progressive manner, as torque is withheld from the tire that is slipping. The Spartan Helical LSD provides smooth engagement, quiet operation, and requires no maintenance. The unit’s 10-pinion design has a strength advantage over an equivalently sized 6-pinion or 8-pinion unit because it has more points of contact and a greater surface contact area to deliver optimal load distribution. This LSD is built tough. The Spartan Helical LSD is a fully assembled unit featuring a forged 8620 grade steel case and stout 8620 alloy internals for superior durability. Spartan Helical LSD Specs Fits Dana 30 Front Differentials 27 Spline, 3.73-And-Up Ratio Enhanced Off-Road Grip, No Compromise of On-Road Drivability Maintenance Free, No Clutches to Rebuild Low Noise, Smooth Engagement, Linear Traction Forged 8620 Grade Steel Case, 8620 Alloy Internals for Superior Durability Recommended Gear Oil: Non-Synthetic 80W-90 GL-5 Use of Friction Modifiers Not Recommended Assembled in the U.S.A. 1-Year Warranty Against Manufacturing Defects Because they give your ride that extra bit of bite, limited slip differentials are ideal for daily drivers that will be driven hard on the street and see extended action on the trail or at the track. Whether you’re facing mud, loose gravel, or steep inclines on the trail or slippery snow or rain on the road, the Spartan Helical LSD will ensure you have unrivalled traction and supreme confidence in your vehicle. Shop Limited Slip Differentials Or Call Now 866-631-0196 Spartan Helical LSD Yukon Dura Grip
How It Works: Pinion Bearing Preload
Pinion bearing preload is a critical step in the differential overhaul process because if you get too heavy handed you have to backtrack and start over. Further, getting this procedure right sets the stage for each following step of reassembly. It should be noted from the get-go that there is a difference between the minimum torque value for the pinion nut and the pinion bearing preload. The process starts by securing the nut to the pre-described minimum torque, then measuring preload and tightening in small increments as required until the target preload is attained.   Pinion Installation Basics Starting with a bare pumpkin, oil the front and rear pinion bearing surfaces in the diff housing then drive the pinion races into the housing using a pinion bearing race driver until they are fully seated. Clean and apply high quality silicone to the races. TIP Treat pinion bearings and bearing races as a mated pair? If you have to change out a pinion bearing remember to install new races as well. Install pre-oiled front pinion bearing and pinion seal. Follow that up with installing the pinion gear and crush sleeve. Next, install pinion the yolk onto pinion splines making sure not to damage the pinion seal when tapping the yoke into place. Finally, apply oil to the pinion nut washer or thrust surface of the pinion itself, put some thread locking compound on pinion threads or threads of the pinion nut, and hand start the nut. Torque Value Versus Preload Tighten the nut until you can feel resistance when turning the yoke back and forth, check torque load. Typical starting points are 55 lb-ft for 3/8-inch bolts/nuts, 75 lb-in for 7/16-inch bolt/nuts, and 125 lb-in for 1/2-inch nuts/bolts. TIP Tap the end of the pinion gear with a punch to ensure the races are fully seated, shake it to evaluate for excessive play. Once you’ve confirmed the nut is properly torqued check for preload. Using a dial-style inch-pound torque wrench spin the nut/pinion to get a running measurement of how much torque it takes to spin the pinion. We’re talking about the running friction or rotating friction of the assembly, not necessarily brake torque. Check, tighten, and check the preload as you go and continue to tighten until you reach the desired/required pinion bearing preload for new bearings as indicated on the accompanying chart. Sneak up on the proper measurement, if you over-torque the pinion nut and get too much preload you will need to replace the crush sleeve and start again. Preload Importance As mentioned earlier, this is the first step of the journey, getting off on the right foot is all the more important. Stability is the end goal of proper preload. Getting this step right prevents the ring and pinion gear from moving in a vertical, horizontal, or diagonal manner. Going too far out of spec will entice gear movement under load when accelerating or in release of load under deceleration, resulting in the reduction of backlash, which causes undue wear, binding, obtrusive noise, and/or driveline vibrations. Shop Gear Set & Install Kits
How It Works: Pinion Bearing Preload
Pinion bearing preload is a critical step in the differential overhaul process because if you get too heavy handed you have to backtrack and start over. Further, getting this procedure right sets the stage for each following step of reassembly. It should be noted from the get-go that there is a difference between the minimum torque value for the pinion nut and the pinion bearing preload. The process starts by securing the nut to the pre-described minimum torque, then measuring preload and tightening in small increments as required until the target preload is attained. Pinion Installation Basics Starting with a bare pumpkin, oil the front and rear pinion bearing surfaces in the diff housing then drive the pinion races into the housing using a pinion bearing race driver until they are fully seated. Clean and apply high quality silicone to the races. TIP Treat pinion bearings and bearing races as a mated pair? If you have to change out a pinion bearing remember to install new races as well. Install pre-oiled front pinion bearing and pinion seal. Follow that up with installing the pinion gear and crush sleeve. Next, install pinion the yolk onto pinion splines making sure not to damage the pinion seal when tapping the yoke into place. Finally, apply oil to the pinion nut washer or thrust surface of the pinion itself, put some thread locking compound on pinion threads or threads of the pinion nut, and hand start the nut. Torque Value Versus Preload Tighten the nut until you can feel resistance when turning the yoke back and forth, check torque load. Typical starting points are 55 lb-ft for 3/8-inch bolts/nuts, 75 lb-in for 7/16-inch bolt/nuts, and 125 lb-in for 1/2-inch nuts/bolts. TIP Tap the end of the pinion gear with a punch to ensure the races are fully seated, shake it to evaluate for excessive play. Once you’ve confirmed the nut is properly torqued check for preload. Using a dial-style inch-pound torque wrench spin the nut/pinion to get a running measurement of how much torque it takes to spin the pinion. We’re talking about the running friction or rotating friction of the assembly, not necessarily brake torque. Check, tighten, and check the preload as you go and continue to tighten until you reach the desired/required pinion bearing preload for new bearings as indicated on the accompanying chart. Sneak up on the proper measurement, if you over-torque the pinion nut and get too much preload you will need to replace the crush sleeve and start again. Preload Importance As mentioned earlier, this is the first step of the journey, getting off on the right foot is all the more important. Stability is the end goal of proper preload. Getting this step right prevents the ring and pinion gear from moving in a vertical, horizontal, or diagonal manner. Going too far out of spec will entice gear movement under load when accelerating or in release of load under deceleration, resulting in the reduction of backlash, which causes undue wear, binding, obtrusive noise, and/or driveline vibrations. Shop Gear Set & Install Kits
4WheelToHeal Charity T-Shirt Design Contest
In conjunction with ICON Vehicle Dynamics and Dynatrac, Yukon is supporting Trail Hero and 4WheelToHeal charities by hosting a T-shirt design contest with participants ranging in age from 4 to 15. 4WheelToHeal is a non-profit organization dedicated to serving wounded and disabled veterans of all branches of military service. Their mission is dedicated to taking wounded and disabled veterans/service members from all branches of the military to off-roading events. These events include: four wheeling, rock crawling, mud bogging, off-road racing, shooting, and camping. Our mission is to boost morale, introduce warriors to the fantastic off-road community and give them an experience they will never forget. A full 100% of donations goes toward supporting warrior events. All proceeds from the contest will go toward 4WheelToHeal and the winner will be given family swag packs from our brands as well as have the shirt for sale as the Trail Hero Charity Tee. Drawing submissions will be accepted from July 4th (Independence Day) to August 7th (Purple Heart Day). Click here for more information