If you're junkyard shopping for an NP205, it's sometimes tough to tell it apart from the chain-driven full-time NP203 case. The quickest way to identify a '205 is by looking for this rear three-bolt cover on the idler shaft.If you're junkyard shopping for an NP205, it's sometimes tough to tell it apart from the c Here's another view of the venerable NP205. Six different versions of this case were made during its long life, with front outputs on both the left and right (shown here) side of the case. One downside to the '205: Its low-range ratio is only 1.96:1.Here's another view of the venerable NP205. Six different versions of this case were made A gear-driven transfer case, like the NP205, uses separate sets of gears to achieve the high- and low-range ratios. The NP205 is one of the most common old-school cast-iron cases, having been installed on 4x4s from each of the Big Three truck makers. They were used as recently as 1991 on GM trucks.A gear-driven transfer case, like the NP205, uses separate sets of gears to achieve the hi Another popular Jeep transfer case is the gear-driven Dana 300, used aboard CJs in the 1980s. Its helical-cut gears are stout enough to handle a V-8's torque and it has a healthy 2.61:1 low-range ratio, but it's plagued with a small, 26-spline output shaft. Advance Adapters sells a beefier, 32-spline shaft that'll solve the problem.Another popular Jeep transfer case is the gear-driven Dana 300, used aboard CJs in the 198 This schematic illustration shows the basics of transfer case operation. Power from the transmission runs into the case and is split to output shafts that are connected to front and rear driveshafts. This particular example is a chain-driven case, which is commonly found on most 4x4s made since the 1980s. It has a planetary gearset that reduces the transmission's gear ratios when the case is shifted into 4-Low.This schematic illustration shows the basics of transfer case operation. Power from the tr Current transfer cases typically put the rear output in line with the transmission input and then offset the front output to one side of the engine or the other. That wasn't always the case, though. The arrows and lines on the Dana Spicer 20 (left) and Dana Spicer 18 show a couple of different power-flow paths. These gear-driven cases were used in Jeeps from the WWII era up through the '70s. The 20s were also used on first-generation Broncos.Current transfer cases typically put the rear output in line with the transmission input a The latest developments in transfer case technology include hybrids that combine full-time and part-time functions in one unit. Shown here is GM's NVG246, otherwise known as the Autotrac system. It uses a number of sensors and its own computer to direct torque when in full-time mode, plus it has the traditional part-time 4-High and 4-Low modes as well. The Autotrac system is found on fullsize GM trucks and has made its way to the midsize TrailBlazer and Envoy SUVs.The latest developments in transfer case technology include hybrids that combine full-time SOURCES Advance Adapters 4320 Aerotech Center Way P.O. Box 247 Paso Robles CA 93446 805-238-7000 Krause Publications 8-00/-258-0929 www.krause.com Drivetrain Specialists Of Las Vegas 7-02/-876-3100 www.drivetrain.com Motive Gear 1001 W. Exchange Ave. Chicago IL 60609 Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!
