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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
Im really happy with the purchase and customer service was excellent
My original OEM transmission failed and Monster had my replacement here really fast. Everything was included the first time and was correct. So far it's been great!
Monster Transmission really came through and even during the holidays. The transmission is well built and we are very pleased.
My transmission went down and I needed one fast. Shipping was fast, customer service is great, and pricing is far better than other options I looked at. Improved shifting and mpg with these transmissions. Will be doing business again!
The salesman Terry was very helpful in the ordering process and making sure I received the correct transmission I needed. It was shipped promptly. After installation the transmission shifted better than factory. I’m still in the process of returning core so I can’t comment on it yet. Thank you Monster transmissions for the great service!
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 $299 Flat-Rate One-Way Shipping to any address, commercial or residential.
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.
No — fluid must be purchased separately. We offer special discounted prices and even cheaper shipping options when you bundle with our fluid at checkout.
Returning your core is simple. Once you are ready to return your core, you can initiate the return process in one of two ways:
Please Note:
Our goal is to make this process as seamless as possible — if you have questions about your core return, just give us a call.