The ATS 850RE 8-Speed Transmission Conversion Kit is the ultimate upgrade for Jeep Wrangler JK owners looking to bring next-generation drivability, torque control, and OEM-grade refinement to their off-road machine. Designed for seamless integration with your 3.6L Pentastar-powered JK (2012–2018), this complete system replaces the factory 5-speed NAG1 automatic with the advanced 850RE 8-speed automatic found in the JL Wrangler. With full support for factory electronics, zero tuning required in most builds, and full plug-and-play operation, ATS makes it possible to experience the 8HP/ZF-based transmission architecture without changing the character of your Jeep — only how well it drives.
This kit is engineered from the ground up to deliver smooth shift logic, aggressive torque multiplication, higher overdrive efficiency, and unmatched off-road control — all while retaining your factory dash functions, gear selector, transfer case, and interior layout. Whether you're daily driving, towing, climbing, or crawling, the 850RE transforms your Wrangler into a smarter, smoother, and more capable machine.
The 850RE — derived from ZF’s highly respected 8HP family — is widely regarded as one of the best automatic transmissions in the industry. Jeep and Ram have used it across numerous models for a reason: it’s fast, refined, durable, and efficient. Compared to the outdated NAG1 or NSG370 transmissions commonly found in JKs, the 850RE offers substantially improved shift speed, gear spread, and low-speed control. With a 7.05 overall gear spread, this unit provides both aggressive first and second gear crawl ratios and efficient cruising gears for fuel economy and RPM reduction.
Unlike legacy transmissions, the 850RE uses advanced clutch-to-clutch shifting, multi-plate friction systems, and computer-driven torque demand modeling to make every shift precise and purposeful. It enables multi-gear downshifting (like 8–6 or 8–4), seamless power delivery, and faster tap-shift response — all managed through ATS' proprietary Translator module that makes everything work natively with your JK electronics.
What sets ATS apart from every other swap kit is simple: full OEM integration. The ATS Translator module connects your Jeep’s ECM, TCM, BCM, brake systems, cluster, cruise control, traction management, and shifter — preserving all factory features and making your 8-speed JK function like a showroom-stock vehicle.
Your factory NAG1 console shifter is reused to control the 850RE, retaining manual +/- tap-shift functionality, auto lockout protection, reverse inhibitor at speed, and accurate shift display. Gears 1–6 show natively on your cluster; 7 and 8 are displayed as “1” and “2,” just as they are on JL applications. ABS, speedometer, tachometer, and remote start all function as expected. This is not a partial or hack job solution — it's complete and seamless, backed by ATS’ decades of drivetrain control innovation.
This particular kit (SKU: 319-916-8380) is engineered specifically for 2012–2018 Jeep JK and JKU models equipped with the 3.6L V6 ERB Pentastar engine. It’s optimized for use with the JL-style transfer case, allowing JK owners to source or reuse a JL 4x4 system while upgrading to the 850RE. The electronics, brackets, mounts, harnesses, and programming are tailored to work with your factory engine calibration and OEM vehicle architecture.
Want to supply your own transmission? ATS supports that too — but this complete version includes an ATS-inspected, dyno-tested 850RE transmission, Torque Converter, Translator module, wiring harness, brackets, cooler lines, and installation hardware. All you need is a JL transfer case and driveline adjustments to complete the swap.
Let’s face it — the NAG1 5-speed automatic was already outdated when it debuted in the JK lineup. With limited gear ratios, sluggish shift mapping, and poor performance under torque loads or large tires, the NAG1 holds back the true potential of your Jeep. Even the strongest rebuilds can’t match the mechanical and software-based refinement of the 850RE.
ATS’ 8-speed conversion offers major benefits in every driving scenario:
This is the full version of the ATS 850RE Conversion Kit with transmission and torque converter, specifically configured for JL transfer case compatibility. Components include:
This kit requires the use of a JL Wrangler Transfer Case (customer-supplied) and minor driveline adjustments (approximately 5” of length due to transmission housing). All core vehicle functions remain unchanged and operate as if the Jeep shipped from the factory with the 850RE drivetrain.
Installation can be completed by any experienced Jeep technician, off-road shop, or advanced DIY builder. The plug-and-play nature of the electronics means no custom wiring, soldering, or calibration is required. The entire electronics portion installs in less than 1 hour. ATS provides detailed instructions and support, and remote assistance is available for configuration of the Translator via PC interface if needed.
The most noticeable driving improvement is in the gear ratios. Here's how the 850RE stacks up against the JK factory transmission options:
| Gear | 850RE (ZF 8HP) | NAG1 (W5A580) |
|---|---|---|
| 1st | 4.71 : 1 | 3.59 : 1 |
| 2nd | 3.14 : 1 | 2.19 : 1 |
| 3rd | 2.10 : 1 | 1.41 : 1 |
| 4th | 1.67 : 1 | 1.00 : 1 |
| 5th | 1.29 : 1 | 0.83 : 1 |
| 6th | 1.00 : 1 | — |
| 7th | 0.84 : 1 | — |
| 8th | 0.67 : 1 | — |
| Reverse | 3.30 : 1 | 3.16 : 1 |
The 850RE provides a dramatically lower first gear for better off-road performance and a higher overdrive gear for highway efficiency. The spread is significantly improved — from the NAG1's 4.32 ratio spread to the 850RE’s 7.05 spread.
This kit is designed for 2012–2018 Jeep JK Wrangler and JKU models equipped with the 3.6L V6 Pentastar engine. It requires use of a JL-style transfer case and assumes NAG1 automatic as the original transmission (manual transmission applications may require additional hardware).
If you want your JK to feel like a JL in all the right ways — smoother, faster, more capable, more responsive — the ATS 850RE conversion is the solution. Whether you’re chasing better crawl ratios, smoother overlanding, or a smarter highway experience, this is the most complete, factory-like drivetrain transformation available for your Jeep.
With decades of innovation in diesel and gas transmission control, ATS leads the aftermarket in factory-grade integration. This conversion system isn’t just another swap — it’s a clean-sheet re-engineering of what your JK should have been. With 100% retention of factory electronics, zero ECM tuning, and OE shifter re-use, it’s the most advanced and complete 8-speed swap on the market.
Backed by ATS’ exclusive warranty, technical support, and product development, this is not a patchwork solution — it's a true OEM+ upgrade for the modern Wrangler builder.
ATS Transmission packages carry a ONE to FIVE YEAR Warranty. There are several exceptions, so refer to the Warranty’s specific terms and conditions . All labor, shipping, or any other charges associated with the product and the product’s failure are not covered under Warranty. Labor and/or shipping charges will not be refunded under any circumstance. After the one-year anniversary date of the original purchase, there is a limited parts replacement Warranty only. Transmissions that are purchased separately outside of a transmission package / stage and are installed without an ATS torque converter carry a 1 year parts only warranty and there is no labor or shipping allowance for transmission only purchases.
In the event of a product failure, the consumer must return the defective product to ATS for inspection before a replacement is sent to the consumer. After ATS inspects the product and completes the failure analysis, the inspection officer at ATS will provide written documentation stating the condition of the product and determine, to the best of his or her ability, what caused the malfunction or complaint. Based on the findings of the inspection report, ATS will determine whether there is a valid Warranty claim. Should a consumer require immediate service, and chooses not to wait for their product to be returned to ATS for inspection, service, and potential repair or replacement, the consumer can purchase a replacement product from ATS. The consumer must pay the full current MSRP, the applicable core charge, and shipping to and from ATS’ shop. When the defective product arrives, ATS will refund the core charge and inspect the product. During inspection, ATS will assess the product for warrantable damage. If the original product has indeed failed under the terms of the original Warranty, ATS will refund the full purchase price for the replacement product only. If the product has failed due to any issue not covered under the original Warranty, ATS will assess charges to the consumer based on any parts necessary to return the product to nominal ATS standards. ATS will deduct the total cost of required parts from the replacement product’s purchase price, and the consumer will be refunded the difference (if any) between the purchase price paid for the replacement product and the cost of parts.
If the consumer can wait for their product to be returned to ATS for inspection, service, and potential repair or replacement, the consumer pays shipping to and from ATS’ shop. When the defective product arrives in Colorado, ATS will inspect the product. ATS will then assess the product for warrantable damage. If the product has failed under the terms of the original Warranty contract, ATS will repair or replace the product – at ATS’s discretion. If the product has failed due to any issue not covered under the original Warranty, ATS will assess charges to the consumer based on any parts necessary to return the product to nominal ATS standards. ATS will bill the consumer for the total cost of parts required for repair of the product, and shipping to and from Colorado, prior to the repaired/replaced product being sent to the consumer.
This section incorporates Section 2, entitled “In the Event of a Failure.” ATS manual transmissions carry a 1-year/12,000 mile Warranty. ATS will not pay for any fluids replaced in the event of a transmission failure. There is no labor or freight warranty coverage on standard transmissions. Manual transmission shafts and gears are not covered by this Warranty on any transmission due to the capability of certain situations to cause stress-loads beyond the structural ability of the shaft or gear.
