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How It Works: The Pros and Cons of Spools & Mini Spools
Spools are all about getting full lockup on a budget… 100% lockup 100% of the time. There are two types of spools: full spools and mini spools. Each attains the same objective, ensuring both drive wheels on a given axle receive full torque and rotate at the same speed all the time. They create a solid axle. Read this article in Español The Spool Compromise As with any drastic, all-in type of modification there are compromises along the way. The spool is no different. Since the axles are locked there is no allowance for situations where the tires need to spin at a different speed… i.e. when the vehicle turns a corner. When this happens the tires chirp, sometimes aggressively, as they struggle to complete the turn. The rubber is the weak link. It’s what gives to allow the vehicle to maneuver. In doing so tires absorb a lot of abuse in the form of significant wear. One should also remember even when not pushed to the level of chirping, any imbalance in wheel speed is scrubbed off by the tires resulting in tire wear. Simply put, spools chew up tires. Another compromise is how the binding within the differential also produces undue stress on the axles themselves. In the long term, axles can bent out of shape because of the torsional stress they are subjected to on the street. Changing Driving Dynamics There is a cause-and-effect scenario going on here. In most cases, running a spool will compromise the turning radius of the vehicle. Further, a spooled driveline can be unforgiving driving on wet/snowy roads as it lacks the finesse to handle conditions that call for the management of different wheel speeds to ensure vehicle stability and control. You can roam the online forums and the street-worthiness of a spool-equipped vehicle is a long-raging debate. Due to their unwieldy nature, we recommend spools as an outstanding choice for dedicated off-road and drag racing vehicles only. Full Spool A full spool replaces the carrier, spider, and sides gears. The unit consists of a snout and a ring flange. The axles are installed in the snout, which is splined to accept the axle shafts. The spool’s ring flange bolts onto the ring gear. So, the ring and pinion do their job, redirecting torque 90 degrees from the driveshaft to the wheels but the housing has lost its ability to differentiate wheel speeds between the wheels. Yukon and USA Standard Gear spools are made from high-quality 8620 steel and heat-treated for additional strength so your differential is ready for extreme action in the name of ultimate traction. Mini Spool A mini spool is less expensive than a full spool. Since it swaps in place of the spider gears and side gears installation is easier, faster, and cheaper than a full spool. Though Yukon and USA Standard Gear mini spools are constructed from heat-treated 8620 alloy steel they are not as stout as full spools because minis rely on the factory carrier for strength. Cost Versus Reward We see our spools as a safer option for those who are considering welding their gears together to get the same solid-axle traction. The big problem is that welding can be done poorly and fail. Either by weak welds or too much heat which compromises the grain structure of the steel causing the gears to become brittle at the weld point and eventually break. When welded diffs let go they can take other components out… which negates any cost savings of welding. In our eyes, spools are only for dedicated off-road and drag racing vehicles. If the vehicle will see the street we urge customers to consider stepping up to a locker or limited slip differential. Cost Versus Capability You can opt for a Spartan Locker, a helical positraction LSD, or a locker. While each of these products represent a step up in streetability, they also embody a rise in cost. A full spool runs around $320 to $375. A Spartan Locker checks in at $400 to $500, provides full lockup, and although it may click occasionally it is far more civilized than a spool. Our helical positraction limited slip differentials start at $600, seamlessly enhance traction on the street, but do not provide full lockup. Yukon’s Grizzly Locker, an automatic locker / selectable locker, starts at about $780 and delivers 100% lockup and the ability to automatically unlock when needed. Of course, pricing is application dependent, but for very little extra investment you can get a Spartan Locker or helical LSD. In many cases you will save money in the long run by not shredding and buying new tires on the regular. If you run expensive big tires like 35-, 37-, or 40-inchers the savings could be substantial. Spools do what they’re intended to do and we build ours with quality materials and top-notch craftsmanship. But these products are narrowly focused on dedicated purpose-built vehicles that aren’t expected to be driven on the street or even make a 90-degree turn. Seriously consider your vehicle’s usage expectations and consider more than the initial cost. Look down the road, moving up to a more versatile, driver-friendly traction device can be the best call for your wallet and your nerves. Shop Full Spools Shop Mini Spools
Upgrade Your Toyota’s Drivetrain With Top-Quality Yukon Parts
Toyota’s have earned a long-running cult-like reputation for off-road tenacity for absorbing abuse and overcoming obstacles on the trail. We get it. And we’ve developed hundreds of part numbers dedicated to the illustrious sombrero badge. If you own a Toyota and want to run with the bear we have Grizzly Lockers, Spartan Lockers, Dura Grip limited slip units, Master Overhaul Gear Kits, complete ring and pinion sets, and more. Going Big-Tire On Your Toyota? Upgrading to bigger wheels and tires is a rite of passage in many off-road circles. Whether you like the look or plan to step up your wheeling game, it’s wise to recognize your 35-, 37-, or 40-inch tires need to do more than merely fit. Getting the larger rolling stock under your rig is the beginning of the process, not the end. The larger-than-stock circumference of big tires change your truck’s final drive ratio and can negatively alter its performance. This change can impact acceleration, freeway cruising, and many aspects of off-road performance. It can also put undo load and wear on your driveline. Changing the gear ratio in your Toyota’s front and rear diffs can turn back the clock and recapture your vehicle’s driving characteristics. Yukon’s Toyota re-gear offerings cover 1996-and-up 4Runners, ’95-and-up Tacomas, and 2000-and-up Tundras. Yukon’s re-gear ring and pinion gear set kits encompass many popular Toyota differentials like the 8.75” rear, 8” clamshell front, and the venerable 8” rear that is featured on countless V6-powered Toyota 4x4s. Jump-start your re-gear kit product search here by listing your Toyota’s specs in the part finder here. In The Mood For More Traction? We can steer you to three great traction options: the Yukon Dura Grip positraction LSD, the Yukon Grizzly Locker, and the Spartan Locker. Where an open diff will freewheel the tire that lacks traction, the Dura Grip limited slip differential uses clutch packs to funnel traction to the tire that has the best grip. In its static state the unit is pre-loaded and provides traction to both wheels. When it’s further loaded… under acceleration, in a fast corner, or when wheel slippage occurs off-road… the clutch packs will apply more torque to the wheel that has the best traction and reduce the transfer of power to the wheel that’s slipping, giving you the balanced traction you need when you need it. All Toyota Dura Grips are heavy duty four-pinion-gear designs built with a high-strength nodular iron case, forged 4320 chromoly spider gears, and top-quality composite clutches. It should be noted that the clutch packs can be rebuilt to bring the unit back to its original performance level or different clutches can be used to fine tune the Dura Grip’s performance to better match your style of driving. Lockers are the big hitter in the off-roader’s arsenal, providing game changing traction on the trail while retaining near-stock drivability on the road. The Yukon Grizzly Locker is a mechanical locker or automatic locker that requires no pneumatic or electronic activation. It replaces the entire carrier assembly and provides incredible clamping force, forged internals, and a forged 8620 low-nickel alloy steel case that is much more robust than the OE carrier it replaces. During on-throttle driving conditions, load is applied to the differential which induces locking, sending 100 percent of the power to both drive tires equally. The Spartan Locker generates reliable, full-lock-up traction at a low cost. The Spartan Locker is 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 consist of a pair of drivers, two side couplers, four alignment pins, four pre-load springs, a hardened cross-pin shaft, a roll pin, and installation wires. These lockers feature heat-treated 9310 steel drivers and couplers for enhanced durability. The advantages of utilizing a Spartan Locker are its 100% lock up and its value. They cost less than half the price of an air-operated locker, and remember this is before factoring in the cost of a pneumatic operating system. Further, Spartan Lockers are about a third the price of a large-frame mechanical locker. Going with a Spartan Locker also pays off when it comes to installation. Since it’s less labor intensive than a large-frame locker, installing a Spartan Locker costs less. The savings can be even more substantial if you handle the install yourself. Got A Tired Drivetrain? When it comes to differential maintenance, Yukon Master Overhaul kits deliver all the high-quality small parts you need to do the job right. Each kit consists of carrier bearings and races, pinion bearings and races, a pinion seal, complete shim kit, ring gear bolts, pinion nut, crush sleeve (if applicable), oil baffles and slingers (if applicable), thread locking compound, marking compound with brush, and a gasket. Yukon Master Overhaul kits are the most comprehensive and complete kits on the market because we do all the research to ensure that every kit is specially tailored to the proper Toyota application. Pre-built Toyota Dropouts Make re-gearing your Toyota easy by ordering a complete assembled dropout. Taking this route delivers a pre-built diff with the ratio you want installed while also saving you the hassle of resetting pre-load and backlash if you were to re-build your existing housing. Yukon heavy-duty dropouts feature upgraded materials and an improved design versus OEM to provide heavy-duty strength, ensuring they are ready to stand up to any abuse you can throw their way. You can elect to upgrade your dropout with double or triple drilled pinion flanges, solid pinion spacers and shims in place of crush sleeves (to better maintain gear setup preload), and you can add a locker or positraction limited slip differential to your build. An added benefit of this approach is installation cost. Going with a rebuilt dropout reduces downtime and saves money on the labor. Further, those comfortable with swapping out the housing can handle the install themselves, saving even more money. Check out our Toyota dropouts for Toyota’s with V6 engines (YP DOTV6) and Toyota’s running the 8" diff (YP DOT8). Yukon also offers Toyota-specific spider gears, yokes, knuckle kits, axles, and small parts like, bearings, u-joints, seals, shims, cross pins, washers, and nuts. The bottom-line message here is hardcore Toyota owners who expect their rides to meet the challenge of the trail or Everyday Joes who primarily drive on the street have found their one-stop shopping destination.
Tales From The Tech Line: Keeping Gears Cool During Break-in
August 11, 2021 - 10:18 AM - Tech Question: I just installed your Yukon limited slip carrier and 3.42 ring and pinion in my GM 10 bolt. I’ve been breaking it in correctly. It’s been about 120 miles so far and it’s still hot to the touch. I can keep my hand on it for about a second or two. When will this thing start running cooler and when would you recommend my first oil change? Thanks. Tech Visitor, RANDYS Worldwide Website Tech Answer: Hot to touch is a poor form of measurement… most people struggle to hold a cup of coffee that is 140°, a shower at 120° will scald you. The normal operating temp of a differential is 175° to 250° depending on the type of driving you’re doing. We recommend using a handheld infrared digital thermometer which cost $15 to $50 to get a more accurate temperature reading. Use your findings in the chart below to determine your oil change interval. Temp Reference / Oil Change Frequency Chart Temperature Frequency 170° 100,000 Miles 200° 50,000 Miles 220° 25,000 Miles 240° 12,000 Miles 260° 5,000 Miles 260°-300° 500-1,000 Miles until temp is controlled Running 250° to 275° is normal for new differentials during the break-in period. It is critical to not tow or take long road trips for first 500 miles as this builds additional heat. At 300° the diff is considered too hot and it should be allowed to cool. Once broken in, the normal operating temperature for a differential for vehicle in stock trim and regular diving is 170° to 220°. Normal operating temperature on vehicles with large tires, undersized differentials, or while towing is 200° to 250°. Remember, a new gear break-in requires an oil change at 500 miles. Gus Pyeatt, RANDYS Worldwide Tech Support For more info on gear oil and additives check out this article. For more info on gear set break-in procedure check out this video.
Tales From The Tech Line: Keeping Gears Cool During Break-in
August 11, 2021 - 10:18 AM - Tech Question: I just installed your Yukon limited slip carrier and 3.42 ring and pinion in my GM 10 bolt. I’ve been breaking it in correctly. It’s been about 120 miles so far and it’s still hot to the touch. I can keep my hand on it for about a second or two. When will this thing start running cooler and when would you recommend my first oil change? Thanks. Tech Visitor, RANDYS Worldwide Website Tech Answer: Hot to touch is a poor form of measurement… most people struggle to hold a cup of coffee that is 140°, a shower at 120° will scald you. The normal operating temp of a differential is 175° to 250° depending on the type of driving you’re doing. We recommend using a handheld infrared digital thermometer which cost $15 to $50 to get a more accurate temperature reading. Use your findings in the chart below to determine your oil change interval. Temp Reference / Oil Change Frequency Chart Temperature Frequency 170° 100,000 Miles 200° 50,000 Miles 220° 25,000 Miles 240° 12,000 Miles 260° 5,000 Miles 260°-300° 500-1,000 Miles until temp is controlled Running 250° to 275° is normal for new differentials during the break-in period. It is critical to not tow or take long road trips for first 500 miles as this builds additional heat. At 300° the diff is considered too hot and it should be allowed to cool. Once broken in, the normal operating temperature for a differential for vehicle in stock trim and regular diving is 170° to 220°. Normal operating temperature on vehicles with large tires, undersized differentials, or while towing is 200° to 250°. Remember, a new gear break-in requires an oil change at 500 miles. Gus Pyeatt, RANDYS Worldwide Tech Support For more info on gear oil and additives check out this article. For more info on gear set break-in procedure check out this video.
How It Works: Gear Oil & Limited Slip Additives
Gear oil keeps components such as the ring and pinion gear set, spider and side gears, limited slip differentials, axles, bearings, and the like lubricated and running smooth. Friction modifiers are additives that improve the performance and efficiency of clutch style limited slip differentials. Understanding how these vital products work is key to properly maintaining your driveline so it performs in the harshest of conditions and lasts for years to come. Differential Oil By The Numbers Yukon recommends non-synthetic 80W-90 GL-5 gear oil in all differentials outfitted with a clutch-type LSD like the Yukon Dura Grip. Oil is rated by its viscosity value. Take a multi-grade oil like an 80W90… The 80W is the viscosity value in the winter, denoted by the W, or more precisely at 0 degrees F. So, an 80W oil is more viscous than a 60W oil at 0 degrees. The second number, 90, refers to the oil’s viscosity rating at 212 degrees F, again a higher number will be more viscous at operating temperature. These numbers are also a function of thickness. So, an 80W oil is thicker than a 60W oil. Multi-grade oils are blended with polymers that slow the rate of thinning as temperatures rise while also slowing the rate of thickening as the mercury falls, determining the viscosity range of the oil. Generally speaking a thinner oil will circulate faster through the differential (or engine for motor oil) during a cold start. Conversely, a thicker oil will protect better when the diff gears generate higher temperatures. The "GL-5" designation identifies how much Sulphur-based friction modifier is present in the oil. This chemical modifier helps the oil function under extreme pressure… like in an LSD. Note: Because of its Sulfur content GL-5 oil is meant to be used on hypoid gears in differentials only; it is too corrosive to be used in transmissions, which require a milder GL-4 formulation because they contain soft metal parts. Yukon offers a number of gear oils in a variety of viscosities and in synthetic and non-synthetic blends. Stand-Alone Friction Modifiers Yukon Friction Modifier Additives are used when more clamping force is needed. This type of product is for clutch-type differentials like the Yukon Dura Grip only, not gear-driven limited slips like our Spartan Helical LSD. Friction modifiers are all about annoying chatter. Yukon Friction Modifier Additive guards against abnormal clutch engagement and/or disengagement (source of the chatter), ensuring the optimal friction characteristics between clutch discs are maintained. These additives can be used to compensate for worn clutches or to “tune” the performance of the clutch packs for a specific application like road racing or vehicles that see a lot of track days. It should be noted that is our own proprietary formula designed specifically for the composite clutches in Yukon LSDs. If you run a Dura Grip, do not use parts store grade modifiers because they are formulated for OEM paper-style clutches. With about one-fifth the abrasive properties these store-bought products will perform like watered down versions of our stuff. These products are vital to the proper upkeep of your differential and knowing how they’re rated and how they do their job is critical to making informed maintenance decisions for your vehicle. Shop Oil & Additives