Advance Adapters JK Atlas 2 Speed Trail Series 2012 - 2018 Auto

The Advance Adapters Atlas 2 Speed Trail Series Transfer Case for 2012-2018 Jeep Wrangler JK with automatic transmission is the ultimate gear-driven transfer case upgrade engineered specifically for the A580 automatic transmission. This JK-specific Atlas features a unique 26 spline input shaft designed to couple directly to the 2012-2018 JK automatic transmission, eliminating the weak factory NP241 transfer case with legendary Atlas strength and reliability.

2012-2018 JK Automatic Transmission Specific Application: This Atlas transfer case is purpose-built for 2012-2018 Jeep Wrangler JK models equipped with the A580 automatic transmission. The A580 automatic overdrive transmission used in JK Wranglers from 2012 to 2018 requires a specific 26 spline input shaft, which is included in this Atlas configuration. This is a critical difference from earlier JK models that used 23 spline transmissions.

Complete Bolt-In Package for JK Wrangler: Unlike universal Atlas transfer cases that require extensive custom fabrication, this JK-specific Atlas 2 Speed is designed to bolt into your 2012-2018 Wrangler JK automatic transmission Jeep with proper fitment and includes all necessary components for a complete installation. The package includes the transfer case, sight tube, cable shifters specifically configured for JK installation, front and rear yokes, all necessary electronics and sensors, complete warranty coverage, detailed installation instructions, and Redline 75W-90 GL4 transfer case oil.

Why Upgrade from Factory NP241 Transfer Case: The factory NP241 transfer case in 2012-2018 JK Wranglers uses a chain-driven design with a 2.72:1 low range ratio. While adequate for stock applications, the NP241 suffers from chain stretch, chain failure under heavy loads, weak aluminum case prone to cracking, limited low-range gearing options, and inability to handle larger tires and increased torque. The Atlas 2 Speed eliminates every weakness of the factory transfer case with all gear-driven construction, multiple low-range ratio options from 3.0:1 to 5.0:1, bulletproof 356-T6 heat-treated aluminum case, synchronized shift-on-the-fly capability, and proven strength handling over 900 foot-pounds of torque.

Trail Series Specifications: The Atlas 2 Speed Trail Series represents the versatile, all-purpose solution for daily drivers and weekend trail rigs. With the 1.25 inch idler gear design, the Trail Series delivers exceptional strength while maintaining smooth on-road operation.

• Series: Trail Series (1.25 inch idler gear design)
• Speeds: 2-Speed (High Range 1:1 and Low Range)
• Available Gear Ratios: 3.0:1, 3.8:1, 4.3:1, 5.0:1
• Input Shaft: 26 spline (specific to 2012-2018 JK A580 automatic)
• Case Material: 356-T6 heat-treated aluminum alloy
• Weight: 110 pounds dry
• Fluid Capacity: 2.0 quarts (1.98 liters)
• Recommended Fluid: Redline 75W-90 GL4 (included)
• Construction: All gear-driven, zero chain design
• Torque Capacity: Over 900 foot-pounds
• Made in USA

Critical JK Automatic Transmission Programming Requirement: Jeep JK Wranglers equipped with automatic transmissions require a Transmission Control Module (TCM) flash to operate correctly with the Atlas transfer case. The Jeep factory coded the stock transfer case ratio of 2.72:1 into the TCM, and installing an Atlas with a different ratio will put the vehicle into limp mode without proper programming. This programming can be accomplished using a Jeep programmer such as Z Automotive Tazer, Vgate OBD2 code reader with Canbus phone app from jscan, or professional Jeep tuning software.

Exact Programming Ratios: The Jeep computer module accepts three decimal places for transfer case ratio programming. While Advance Adapters rounds the ratios to one decimal place for simplicity, the exact ratios required for TCM programming are:

• 2.0:1 = exactly 2.11:1
• 3.0:1 = exactly 3.030:1
• 3.8:1 = exactly 3.824:1
• 4.3:1 = exactly 4.286:1
• 5.0:1 = exactly 5.048:1

Entering the exact three-decimal ratio ensures proper speedometer calibration, traction control operation, anti-lock brake function, and overall drivetrain integration.

Important: Atlas 4 Speed Not Available for JK Automatic: Due to computer programming limitations in the Jeep drivetrain control systems, the Atlas 4 Speed transfer case is not compatible with 2012-2018 JK Wranglers equipped with automatic transmissions. The 2-speed Atlas is the only Atlas option for JK automatic transmission applications.

Available Gear Ratios Explained:

3.0:1 Ratio - The perfect all-around ratio for JK Wranglers running 35-37 inch tires. Provides excellent low-range torque multiplication while maintaining reasonable crawl speeds. The 3.0:1 ratio works exceptionally well with the factory 3.6L Pentastar V6 engine, keeping engine RPM in the powerband during technical terrain. Ideal for weekend trail riders who split time between highway driving and moderate rock crawling.

3.8:1 Ratio - Increased crawling capability for serious rock crawling and steep climbs. The 3.8:1 ratio is the sweet spot for JK Wranglers with 37-40 inch tires and moderate builds. Delivers strong low-range torque while keeping the engine in its optimal power range on steep grades. Popular choice for built JK Wranglers tackling challenging trails like Moab, Rubicon Trail, and technical East Coast rock gardens.

4.3:1 Ratio - Serious low-range gearing for extreme rock crawling and ultra-slow technical terrain. Recommended for heavily built JK Wranglers with 40-42 inch tires, heavy armor, and significant weight. The 4.3:1 ratio provides exceptional torque multiplication for the most challenging obstacles while maintaining precise throttle control at crawl speeds.

5.0:1 Ratio - Maximum crawl ratio for the slowest technical terrain and competition use. The 5.0:1 ratio is designed for extreme builds with 42+ inch tires, full armor, winches, and maximum weight. Delivers unmatched low-speed control and torque delivery for King of the Hammers-level terrain and professional rock crawling competition.

Gear-Driven Atlas Advantage: The Advance Adapters Atlas revolutionized transfer case design by eliminating the weak chain-driven architecture used in factory transfer cases. The all gear-driven design uses massive helical-cut gears supported by needle bearing elements and precision-matched 8620 steel shafts. This construction delivers quiet operation, shift-on-the-fly capability, and bulletproof reliability under extreme loads.

Construction and Engineering Excellence: The solid one-piece case design is manufactured from 356-T6 heat-treated aluminum alloy, the same aerospace-grade material used in the structural access cover and all exterior components. Heavy-duty planetary gears feature BorgWarner synchronizers for smooth shifting under load, something impossible with chain-driven transfer cases. Ruggedly designed output shafts are supported by large taper bearing sets for maximum durability under extreme torque loads.

JK-Specific Installation Considerations: The Atlas 2 Speed is approximately 2.5 inches longer than the factory NP241 transfer case. This additional length typically requires rear driveshaft shortening and may require front driveshaft modification or replacement. Most 2012-2018 JK installations are completed without body lifts, though a body lift can provide additional clearance for exhaust and crossmember modifications. Professional driveline shops can properly shorten and balance driveshafts to ensure smooth operation.

Cable Shifter Configuration: This Atlas transfer case comes configured with cable shifters specifically designed for Jeep JK installation. The cable shifter design allows flexible mounting options and eliminates the need for complex linkage fabrication. The shifter provides independent control of front and rear axle engagement, giving you complete control over your drivetrain configuration.

Speedometer and Electronics Integration: The Atlas includes all necessary electronics and speed sensors for proper integration with JK Wrangler computer systems. When properly programmed with the correct transfer case ratio, the Atlas integrates seamlessly with factory speedometer, anti-lock brakes, traction control, and stability control systems.

What's Included with Your Atlas: Every Atlas 2 Speed for 2012-2018 JK automatic transmission includes the complete transfer case assembly with 26 spline input shaft, sight tube for easy fluid level inspection, cable shifters pre-configured for JK installation, front and rear yokes compatible with JK driveshafts, all necessary electronics and speed sensors, complete warranty documentation, detailed installation instructions specific to JK Wrangler, and Redline 75W-90 GL4 transfer case oil pre-filled.

Custom Built-to-Order Process: Each Atlas transfer case is custom built to order by Advance Adapters in their Paso Robles, California facility. After placing your order through Skinny Pedal Racing, you will be contacted by technical specialists to confirm your specific configuration including verification of your 2012-2018 JK with A580 automatic transmission, desired gear ratio selection, output shaft drop direction confirmation, yoke configuration verification, and any special requirements for your build.

Typical Build Lead Time: Due to high demand and the custom nature of Atlas transfer cases, current lead times are 6-7 weeks from order confirmation to shipment. This build time ensures each Atlas is manufactured to exact specifications and thoroughly tested before leaving the factory.

Installation Professional Recommendation: While experienced home mechanics can install the Atlas transfer case, we recommend professional installation by a qualified Jeep performance shop familiar with JK drivetrain modifications. Professional installation ensures proper driveshaft modifications, correct transfer case programming, proper fluid levels, and verification of all electronic integration.

Legendary Atlas Durability and Reputation: Since 1995, the Advance Adapters Atlas has established an unmatched reputation for strength, reliability, and performance. With over 30,000 units sold worldwide, the Atlas has proven itself from daily driver Jeeps to King of the Hammers competition vehicles. Many original Atlas transfer cases from 1995 remain in service today, testament to their precision engineering and bulletproof construction.

Trail Series vs G2 Pro Series: The Trail Series features a 1.25 inch idler gear design optimized for daily drivers and weekend trail use with gear ratios from 3.0:1 to 5.0:1. The G2 Pro Series (sold separately) features a 1.5 inch idler, 300M output shafts, super-finished gears, and is designed for competition racing and extreme high-performance applications.

Why Choose Skinny Pedal Racing: Skinny Pedal Racing specializes in high-performance drivetrain components for Jeep Wrangler enthusiasts. We work directly with Advance Adapters to ensure your Atlas transfer case is configured correctly for your specific 2012-2018 JK automatic transmission application. Our technical specialists have extensive experience with JK Atlas installations and can guide you through the entire process from initial order to post-installation programming.

Warranty and Support: Every Atlas transfer case includes comprehensive warranty coverage backed by Advance Adapters. The warranty covers manufacturing defects and material failures when the transfer case is used as intended. Detailed warranty information is included with each transfer case.

The Atlas Transformation: Installing an Atlas 2 Speed Trail Series transfer case transforms your 2012-2018 Jeep Wrangler JK's off-road capability. Experience the difference of true gear-driven strength, synchronized shifting under load, multiple low-range options for any terrain, bulletproof reliability you can trust, and legendary Atlas performance proven by over 30,000 satisfied customers worldwide.

Made in USA: Every Atlas transfer case is designed, engineered, and manufactured by Advance Adapters in Paso Robles, California. American craftsmanship, precision CNC machining, and rigorous quality control ensure every Atlas meets the highest standards of performance and reliability.

Order Your JK Atlas Transfer Case: Upgrade your 2012-2018 Jeep Wrangler JK automatic transmission with the industry-leading Atlas 2 Speed Trail Series transfer case from Skinny Pedal Racing. Contact us to discuss your specific application and let our experts help you select the perfect gear ratio for your build. Transform your JK's capability with Atlas strength and reliability.