Step up to confident performance for light-duty trucks, SUVs, and performance cars. The RoadReady 6L80 is a 6-speed automatic designed for smooth shifts, efficient cruising, and solid torque handling—ideal for daily driving, towing, and spirited weekend runs.
Built to OEM-equivalent standards by a Monster-Approved manufacturing partner, each unit is precision-assembled and tested for reliable power transfer and long-term durability.
Note
Easy to order. They answered all my questions. Shipping was fast. Drives better than when I bought it new.
I ordered the road ready (stock rebuild) 6l80. Shipping was quick, communication was great, installed and programmed and my vehicle is running great! Shifts are super smooth and has a great warranty. Will be ordering more. Thanks.
Very fast and accurate shipping easy to use tuner
The unit showed up in a timely manner an was in a plastic container. Did have two quarts of fluid that had leaked in to the bottom. The unit was clean and after installing it vehicle is running an driving great. No issues with install and this makes the 5th unit I have put in different vehicles.
Great quality and feels great driving, perfect fit on my suburban. Very satisfied with my purchase.
In-stock transmissions usually ship the next business day.
Custom builds or out-of-stock units typically ship within 4–6 weeks.
Need it sooner? Call us — we can often make special arrangements.
We offer the most comprehensive coverage in the industry:
Extend warranties are included on all Transmission Purchases read more HERE.
No — we offer a $364 Flat-Rate One-Way Shipping to any Address.
If you find a better rate, you're welcome to arrange your own shipping.
No — due to the variety of tune files required, we do not pre-program 6L80/6L90 transmissions.
Each vehicle may require a unique calibration. For best results, programming should be done after installation, using a scan tool or tuning software.
While we don’t provide direct tuning, we can recommend trusted tools (HP Tuners, MDI2) and shops for programming assistance. See our full Instruction Manual for all options.
In most cases, it’s not the transmission itself. The leak is usually caused by a failed seal inside the driveshaft slip yoke, not the transmission’s tail housing.
We recommend installing a Solid Yoke available from GM or a Local GM Dealer to fix the issue properly.
Each Monster 6L80 transmission includes a torque converter matched to the power level and intended use:
Custom Stall Available for TrackMonster: Let us know your cam, gearing, and use case — we can tailor the stall speed to your build.
Each Monster 6L80 build is engineered for a specific horsepower range to ensure long-term durability and reliable performance:
Note: All HP ratings assume proper tuning, cooling, and supporting mods for your specific application.
Returning your core is simple. Once your old transmission is ready for pickup, you can start the return process online or call our Customer Service Team.
Please Note:
Our goal is to make this process as easy as possible. If you have questions about your core return, give us a call and we’ll help.
Start Core Return