Advance Adapters Atlas 2-Speed Trail Series Transfer Case - Custom Built

The Atlas 2-Speed is the gear-driven transfer case the off-road world measures everything else against. Advance Adapters has been building it since 1995, with over 30,000 Atlas cases sold, and it's still the go-to when a chain-driven factory case just isn't going to live behind your build. Rock crawling, desert running, mud or a daily driver that sees real trails, it handles all of it and still drives right on pavement.

Every case is built to order in the USA by Advance Adapters, so you spec it exactly how your rig needs it using the options above.

Why the Atlas

• All-gear design with helical-cut gears, no chain to stretch or snap
• BorgWarner synchronizers for shift-on-the-fly
• 356-T6 heat-treated aluminum case with precision-machined internals
• Heavy-duty 32 spline front output shaft is now standard
• 1:1 high range for the highway, your pick of low range for the trail
• Made in the USA

Build it your way

• Low range: 2.1:1, 3.0:1, 3.8:1, 4.3:1 or 5.0:1
• Front output: driver or passenger side, clockable in 7° steps from 0 to 35°
• Transmission adapter: GM, Ford and Toyota adapters available, or a divorced case with an input yoke
• Tailhousing: standard (accepts '87 and newer Jeep speedometer or the Atlas mechanical speedometer), short (2" shorter, no speedometer), GM VSS electric, or HD with a 300M output shaft
• Input shaft: 10 through 35 spline, plus 300M competition shafts
• Yokes: 1310, 1330, 1350 and 1410 in CV, non-CV and flange styles (U-joints not included)
• Shifters: universal, cable, single stick and Jeep or Ford specific kits

Race Case upgrade

The Race Case adds a 300M input shaft and cluster gears plus ISF-treated gears for about 15% more torque capacity, longer gear life, cooler running and less gear noise. It requires the HD tailhousing with the 300M output shaft.

Tailhousing notes

The standard tailhousing lets you calibrate the speedometer for tire and gear changes. The HD tailhousing is the same thing with a 300M output shaft that's rated about 130% stronger, built for competition and big horsepower. The short tailhousing is 2" shorter with no speedometer, made for crawlers and tight spaces. The GM VSS tailhousing takes a sensor and reluctor for computer-controlled engines and transmissions, and it's drilled and tapped for a low range switch.

Ordering a speedometer? Send us your tire size and axle ratio after you order so the gear gets set up right.

Which input shaft do I need?

Find your transmission below. The last column is the Atlas input shaft to pick in the Input Shaft dropdown above. "Stock OEM" means the case bolts to that transmission with no adapter. If there's a part number in the Adapter column, that's the Advance Adapters adapter your transmission needs. Many of them are in the Transmission Adapter dropdown above, and you can find others in our Atlas Adapter collection.

• 23 spline (short) is the A23SHORT input. 23 spline (long) is A23LONG.
• 32 spline / HD and 29 spline / HD rows can take the 300M competition input shafts if you're making big power.
• 2012 and newer Jeep JK automatics (W5A580) use the A26 26 spline input.

Don't see your transmission, or not sure? Ask us before you order. Custom adapters are available, and every Atlas order gets confirmed with Advance Adapters before it's built.

Atlas specs

Warranty

Advance Adapters covers Atlas gear sets and castings for the life of the original owner (non-transferable). Everything else, like shafts, bearings, gaskets and hardware, gets a limited 1-year warranty from the day the case ships. Misuse, abuse, the wrong gear oil, low oil level or an install that skips the instructions will void it.

Sales tax will be charged after the sale.