SportMonster Chevy 6L90E Transmission and Torque Converter

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:

• StockMonster: 4 Year (1 Year Manufacture, 3 Years from Extend)
• StreetMonster: 5 Years (2 Year Manufacture, 3 Years from Extend)
• SportMonster: 6 Years (3 Year Manufacture, 3 Years from Extend)
• TrackMonster: 4 Year (2 Year Manufacture, 3 Years from Extend)

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:

• StreetMonster: 1600 RPM stall, paired with mild upgrades for vehicles with light bolt-ons or basic tuning.
• SportMonster: Includes a 1800–2000 RPM stall converter for better launch and mid-range performance. Great for cammed street builds or bolt-on performance.
• TrackMonster: Comes with a 2300–2500 RPM stall converter built for drag racing, aggressive cams, or boosted applications.

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:

• StreetMonster: Handles up to 100 HP over stock. Great for lightly modified vehicles with tuning, exhaust, or intake upgrades.
• SportMonster: Built for up to 650 HP. Ideal for performance street builds, mild forced induction, or cammed LS engines.
• TrackMonster: Rated up to 1000 HP. Our strongest option with billet internals and racing components for drag strip dominance or high-boost builds.

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:

• Fill out our Core Return Form (available online) using the button below.
• Or call our Customer Service Team at 800-708-0087 to schedule your return freight pickup.

Please Note:

• The customer is responsible for the return shipping cost.
• A flat-rate fee of $299 will be deducted from your core refund to cover return freight and handling. If Round Trip Shipping is not Prepaid Upfront.
• The core must be the same model and not cracked or damaged beyond rebuild.

Our goal is to make this process as seamless as possible — if you have questions about your core return, just give us a call.