Propickup Digital Magazine
Issue link: https://read.dmtmag.com/i/105105
it has advanced programming options in its electronic traction controls to help drivers get out of difficult situations. Besides increased brake-pad wear, the biggest drawback to electronic traction controls is that they may cut engine power and work to eliminate all wheelspin. For situations such as climbing a steep hill on loose dirt or slogging through deep sand, the driver needs power and some wheelspin to maintain momentum or "dig out." That's where the mechanical traction aids provide the most effective assistance. The other big drawback is driver frustration when the computer intrudes during aggressive off-roading, like when you lay into the throttle in sand or heavy mud to get the tires to clean and keep forward momentum. Pickup manufacturers give drivers the option to turn off traction and stability controls, and some vehicles do it automatically when in certain 4WD modes. But even that might not be enough to keep your truck from getting stuck. TRACTION UPGRADES The work and recreational needs of many truck owners may require upgrading of a stock vehicle's drivetrain with some type of mechanical traction assistance. The actual workload and owner's pocketbook will determine the best option. Limited-slip differentials have been around since the '50s. They may use internal friction ue clutches – either flat or cone style – or a unique worm-gear arrangement to limit torque to e the spinning wheel and transfer power to the wheel with greater traction. Clutch-type LSDs will wear out and need to be serviced or replaced. Currently there is o only one gear-type LSD in the aftermarket, so availability may be a problem. Most truck owners seeking a traction upgrade prefer a locker. There are two types: automatic and selectable. The automatic locker distributes torque equally to both wheels at all time by literally locking the axes together. When going ws through a turn, the locker "unlocks" and allows the outside wheel to rotate faster than the n inside wheel. The unit then locks again when torque is applied. Automatic lockers are strong but also noisy, may increase tire wear and may deliver a harsh ride on the street. These e aftermarket automatic lockers are not to be confused with the factory automatic lockers that normally run with an open differential then automatically engage the locked mode when sensing wheelspin. Ford offers an electronic-locking differential for the rear axle on most Super Duty SRW axles. Other 2500/3500 trucks can get a limited-slip differential option for the rear, but there may be some restrictions depending on the trim level. LIMITED-SLIP DIFFERENTIALS BUYERS GUIDE P DIFFERENTIALS E S AUBURN LIMITED SLIP Auburn offers two versions of its LSD, including a Pro Series that has a more aggressive torque bias. Heavier trucks should certainly consider the Pro Series. The Auburn LSD is a cone-clutch design and requires a friction modidifier additive in the lubricant. Coneeclutch LSDs are not rebuildable because ecause the cones are specifically matched to the case; however, cone LSDs generally last longer than clutch types. Also, ll l t l th l t h t Al Auburn has a D-REX program so owners with units less than four years old can trade in for a new Auburn LSD for the about the same cost to rebuild a comparable clutch-type LSD. Street price: $325 to $650 for the standard LSD and $400 to $550 for the Pro Series. EATON TRUE TRUETRAC A quiet and smooth-operating LSD, the Truetrac utilizes a helical gear design and is pretty quie mu much maintenance free and doesn't require a friction-modifier in the lubricant. It's built w with forged gears under tight tolerances for a strong mesh. The design is fully autom matic. Long-time enthusiasts may remember this differential under the Tractech brand, which was purchased by Eaton about ch six years ago. The Truetrac is often a o. strong choice ce fo for a front diff differential due e to its negligible n impact on steering and tough reputation, but experts may warn against using tires over 33 inches tall. Street price: $375 to $750 EATON POSI The Eaton Posi h hasn't changed in design but materials and tolerances are much improved since the unit was first introduced in the '50s. The Posi uses carbon-disc clutch packs that are pre preloaded by a central spring assembly and located behind each differential side gear. One of the Posi's benefits is that it can be "tuned," depending on the spring strength an and the preload. The Posi can also be rebuilt after the clutches wear out. While the Posi isn't the most effective traction-control option, it's affordable and has built one of the most loyal followings of any automotive brand. or For those truck owners w h with an open rear differential seeking add tional traction additional f i h i d b nclement for a tow rig or those worried about inclement derweather, the Posi merits strong consideration. Street price: $475 to $800 propickupmag.com PROPICKUP 49