Atlas II 4.3:1
Why it's cool: The folks over at Advance Adapters created a legend with the Atlas II transfer case. Again, we can use Top Truck Challenge as an indicator of how tough these 'cases are. The Atlas is the second-most popular transfer case with TTC competitors, with around 30 percent of the field running one in their rigs from 2004 to 2006. The rugged one-piece case is made from 356-T6 heat-treated aluminum alloy, so it can take a beating. It houses strong helical-cut gears supported by needle bearings that are precision-matched to strong 8620 shafts. These shafts are supported by large taper bearing sets. The Atlas II is available with 11 different input-shaft splines and two front output shafts; either 26- or 32-spline. That's not all. We love the way the 'case is available in six different low-range ratios. Our favorite is 4.3:1 because it's a do-it-all ratio. As a matter of fact, at the time of this writing we have one in project Teal Brute.
How you can get one: The team at Drivetrain Warehouse can hook you up. You can also order an Atlas II directly from Advance Adapters.
Dana 300
Why it's cool: A direct descendent of the Dana/Spicer 18 and the Dana 20, the 300 is a strong 'case with helical-cut low-range gears (unlike the Dana 20). This translates to quiet low-range operation. This 'case was found primarily in '80-'86 Jeep CJs and in the '80 Scout, though they do not share the same bolt pattern. The 300 features geardrive and a cast-iron case and weighs in at around 85 pounds. The 300 also offers 2.62:1 low-range gearing as opposed to the Dana 20's 2.0:1. The Dana 300 was the last cast-iron, geardrive transfer case installed in a factory Jeep.
How you can get one: High Impact Transmission & Gear offers rebuilt units as well as a full range of rebuild parts. 4xHeaven can rebuild your 300 for you or be a parts source. Novak Conversions offers a variety of adapters which allow the 300 to be bolted to a variety of automatic and manual transmissions.
Borg-Warner 13-56
Why it's cool: The 2.62:1 low-range 13-56 was used primarily in '87-'96 Ford F-Series and Bronco trucks. Even though it has an aluminum housing and chaindrive, it is extremely durable and Ford used it behind a wide variety of powerplants including the 7.3L diesel and the 460ci V-8 gas engines with great success. Normal wear items include bearings and the chain. If the 13-56 has an Achilles' heel, it is the oil pump, which can break loose and rotate on the drive, causing a loss of lubrication. Some pre-empt this problem by running a sheetmetal screw through the pump and into the housing. The folks over at Jeff's Bronco Graveyard also note that because the 13-56 mounts only to the transmission, it is susceptible to axlewrap damage. They recommend stabilizing the case or controlling axlewrap.
How you can get one: Give the folks at Bronco Graveyard a shout. They have rebuilt 13-56s as well as a full line of standard hard parts. By the time you read this, they'll have a slip-yoke eliminator kit available for Ford pickups too.
Stak Monster Box Three-Speed
Why it's cool: Let's see ... cast 356 alloy-aluminum T6 hardened housing, helical-cut ASTM alloy 8620 heat-treated gears, ASTM alloy 8620 heat-treated shafts, 32-spline output shafts, high-quality tapered roller bearings, and more than 60 3/8-16 stainless-steel socket-head cap screws. Need we say more? OK, we will. The Monster Box is clockable in 4-degree increments up to 360 degrees, Jeep TJ-specific shifters are available, and there are a large number of yoke and flange options. Speaking of options, you can get a parking brake, vehicle speed sensor, and a 4WD light. All of these cool things and two low-range gears to choose from on the trail. Ain't life grand?
How you can get one: Contact Stak 4x4